This document summarizes several models for screening hepatoprotective drugs. It describes in vitro models including hepatic stellate cell culture, liver slice systems, and assays measuring proline hydroxylation and collagen synthesis. It also outlines several in vivo rat models, including those using CCl4, allyl alcohol, bile duct ligation, and galactosamine to induce liver fibrosis, necrosis, or damage and evaluate potential hepatoprotective effects of test compounds. Parameters measured include liver enzymes, hydroxyproline content, histology, and serum markers of collagen synthesis. These preclinical models allow evaluation of drug candidates for protection against liver injury.
This document describes various in vivo and in vitro models used for screening potential antiparkinsonian drugs. Some key in vivo models mentioned include: 1) antagonism of tremors induced by tremorine/oxotremorine in mice, 2) use of the MPTP model in monkeys to induce Parkinson's disease-like symptoms, and 3) antagonism of sedation induced by reserpine in mice. Important in vitro/ex vivo models include measuring dopamine-stimulated adenylyl cyclase activity and radioligand binding studies for dopamine receptors. The document provides details on the procedures, evaluations, and modifications of these various screening models.
Screening method of nootropics vikas malikVikasMalik68
1. The document describes various methods for screening nootropic substances, including in vivo, in vitro, and molecular-level experiments.
2. Some key in vivo methods discussed are passive avoidance testing in rats/mice, active avoidance conditioning experiments, and electrophysiological studies like long-term potentiation experiments in hippocampal brain slices.
3. In vitro screening methods outlined involve measuring inhibition of acetylcholinesterase activity from rat brain tissue and butyrylcholinesterase activity from human serum. Molecular-level experiments involve analyzing effects on acetylcholine receptors and neurotransmitter release.
This document provides information about Alzheimer's disease including its definition, history, pathophysiology, mechanisms, signs and symptoms, treatments, and screening methods. It discusses how Alzheimer's was first identified by Dr. Alois Alzheimer in 1906 and the characteristic brain abnormalities he observed. The two main hypotheses for the disease mechanism are the amyloid beta hypothesis and tau hypothesis which involve the accumulation of amyloid plaques and neurofibrillary tangles respectively. Several in vitro and in vivo screening methods are described to test potential drugs for treating Alzheimer's including assays measuring acetylcholinesterase inhibition and animal behavior tests.
Experimental evaluation of antifertility agents
The document discusses various in vivo and in vitro methods to evaluate potential antifertility agents in males and females. It describes tests to determine if compounds interfere with ovulation, implantation, fertilization or early embryo transport in females. For males, it outlines assays to test if agents affect spermatogenesis, sperm function or fertility. The document also provides protocols for characterizing the estrogenic, progestational, androgenic or anti-hormonal properties of test compounds. It details rat, rabbit and chicken models commonly used to screen for contraceptive activity and hormonal effects.
This document describes various in vivo and in vitro models used to study antihypertensive and vasodilator drugs. In vivo models include the Goldblatt hypertension model in rats, chronic renal hypertension in rats and dogs, and the tail cuff method in rats. In vitro models include ACE inhibition in guinea pig ileum and β1 sympatholytic activity in guinea pig atria. The document also provides details of the procedures for these models.
This document describes several screening methods used to assess the effects of drugs on motor coordination and muscle function in mice. The methods include the open field test, hole board test, inclined plane test, vertical screen test, rotarod test, and chimney test. Each method is briefly described, including the purpose, apparatus used, procedures, and outcomes measured. The tests evaluate behaviors like locomotion, exploration and curiosity that can be altered by sedative or stimulant drugs.
pre clinical Screening for anti asthmatic drugsDHINESHKUMAR V
This document describes various pre-clinical screening methods for anti-asthmatic drugs, including in vitro, isolated organ, and in vivo models. In vitro methods include the CULTEX technique using bronchial epithelial cell cultures and histamine receptor binding assays using guinea pig brain membranes. Tests in isolated organs involve measuring spasmolytic activity in guinea pig lung strips. In vivo models include tests in anesthetized guinea pigs to evaluate bronchospasmolytic effects and protection against anaphylactic shock or serotonin/histamine-induced asphyxia. Overall, the document outlines the most common pre-clinical tests used to evaluate potential anti-asthmatic effects prior to clinical trials.
This document provides information on screening methods for antidiabetic drugs. It discusses various in vivo and in vitro models used to screen drugs, including chemically-induced diabetes models using alloxan and streptozotocin in animals, genetically diabetic animal models like NOD mice and BB rats, and isolated tissue and cell-based in vitro models. A variety of animal models aim to mimic types 1 and 2 diabetes by destroying pancreatic beta cells or inducing insulin resistance. These preclinical models are used to evaluate new drugs' ability to lower blood glucose levels and treat diabetes symptoms before human trials.
This document describes various in vivo and in vitro models used for screening potential antiparkinsonian drugs. Some key in vivo models mentioned include: 1) antagonism of tremors induced by tremorine/oxotremorine in mice, 2) use of the MPTP model in monkeys to induce Parkinson's disease-like symptoms, and 3) antagonism of sedation induced by reserpine in mice. Important in vitro/ex vivo models include measuring dopamine-stimulated adenylyl cyclase activity and radioligand binding studies for dopamine receptors. The document provides details on the procedures, evaluations, and modifications of these various screening models.
Screening method of nootropics vikas malikVikasMalik68
1. The document describes various methods for screening nootropic substances, including in vivo, in vitro, and molecular-level experiments.
2. Some key in vivo methods discussed are passive avoidance testing in rats/mice, active avoidance conditioning experiments, and electrophysiological studies like long-term potentiation experiments in hippocampal brain slices.
3. In vitro screening methods outlined involve measuring inhibition of acetylcholinesterase activity from rat brain tissue and butyrylcholinesterase activity from human serum. Molecular-level experiments involve analyzing effects on acetylcholine receptors and neurotransmitter release.
This document provides information about Alzheimer's disease including its definition, history, pathophysiology, mechanisms, signs and symptoms, treatments, and screening methods. It discusses how Alzheimer's was first identified by Dr. Alois Alzheimer in 1906 and the characteristic brain abnormalities he observed. The two main hypotheses for the disease mechanism are the amyloid beta hypothesis and tau hypothesis which involve the accumulation of amyloid plaques and neurofibrillary tangles respectively. Several in vitro and in vivo screening methods are described to test potential drugs for treating Alzheimer's including assays measuring acetylcholinesterase inhibition and animal behavior tests.
Experimental evaluation of antifertility agents
The document discusses various in vivo and in vitro methods to evaluate potential antifertility agents in males and females. It describes tests to determine if compounds interfere with ovulation, implantation, fertilization or early embryo transport in females. For males, it outlines assays to test if agents affect spermatogenesis, sperm function or fertility. The document also provides protocols for characterizing the estrogenic, progestational, androgenic or anti-hormonal properties of test compounds. It details rat, rabbit and chicken models commonly used to screen for contraceptive activity and hormonal effects.
This document describes various in vivo and in vitro models used to study antihypertensive and vasodilator drugs. In vivo models include the Goldblatt hypertension model in rats, chronic renal hypertension in rats and dogs, and the tail cuff method in rats. In vitro models include ACE inhibition in guinea pig ileum and β1 sympatholytic activity in guinea pig atria. The document also provides details of the procedures for these models.
This document describes several screening methods used to assess the effects of drugs on motor coordination and muscle function in mice. The methods include the open field test, hole board test, inclined plane test, vertical screen test, rotarod test, and chimney test. Each method is briefly described, including the purpose, apparatus used, procedures, and outcomes measured. The tests evaluate behaviors like locomotion, exploration and curiosity that can be altered by sedative or stimulant drugs.
pre clinical Screening for anti asthmatic drugsDHINESHKUMAR V
This document describes various pre-clinical screening methods for anti-asthmatic drugs, including in vitro, isolated organ, and in vivo models. In vitro methods include the CULTEX technique using bronchial epithelial cell cultures and histamine receptor binding assays using guinea pig brain membranes. Tests in isolated organs involve measuring spasmolytic activity in guinea pig lung strips. In vivo models include tests in anesthetized guinea pigs to evaluate bronchospasmolytic effects and protection against anaphylactic shock or serotonin/histamine-induced asphyxia. Overall, the document outlines the most common pre-clinical tests used to evaluate potential anti-asthmatic effects prior to clinical trials.
This document provides information on screening methods for antidiabetic drugs. It discusses various in vivo and in vitro models used to screen drugs, including chemically-induced diabetes models using alloxan and streptozotocin in animals, genetically diabetic animal models like NOD mice and BB rats, and isolated tissue and cell-based in vitro models. A variety of animal models aim to mimic types 1 and 2 diabetes by destroying pancreatic beta cells or inducing insulin resistance. These preclinical models are used to evaluate new drugs' ability to lower blood glucose levels and treat diabetes symptoms before human trials.
Screening of ANTIFERTILITY AGENTS and APHRODISIACSHimaniTailor
This document discusses evaluation and screening models for antifertility and aphrodisiac agents. It describes various in vivo and in vitro methods used to test potential antifertility drugs in females, including tests for anti-ovulatory activity like HCG-induced ovulation in rats and cupric acetate-induced ovulation in rabbits. It also discusses screening methods for assessing progestational and oestrogenic activity. For aphrodisiacs, it covers mechanisms of action and potential agents like sildenafil citrate and testosterone, as well as guidelines for conducting experiments on sexual behavior in rats.
Preclinical Screening of Antiasthmatic DrugsShubham Kolge
Bronchial asthma is characterized by both bronchoconstriction and airway inflammation which leads to bronchial hyperresponsiveness to various stimuli. Different mediators are implicated in asthma. As the precise etiology is not known and multiple biochemical processes are triggered by different causative factors, it is difficult to have a single drug which can effectively and simultaneously act upon different mediators. This led to an intense search for potent and safe antiasthmatic drugs. This presentation intends to compile different screening methods for the evaluation of new candidate drugs with potential for the treatment of asthma. These include in vitro, in vivo, receptor binding and enzymatic methods.
This document summarizes screening methods for potential antiparkinson agents. It describes several in vivo and in vitro models used to test compounds. The key in vivo models discussed are:
1. Tremorine and oxotremorine antagonism in mice, which tests a compound's ability to reduce tremors induced by these muscarinic agonists.
2. The MPTP model in monkeys and mice, which uses MPTP to damage dopaminergic neurons and induce Parkinson's-like symptoms that can be reversed or reduced by test compounds.
3. Reserpine antagonism in rats, which tests if a compound can reduce sedation and motor impairment caused by reserpine depletion of cate
The document describes several in vitro and in vivo methods used to study anti-allergic and anti-inflammatory drugs. In vitro methods include inhibition of histamine release from mast cells and inhibition of T cell proliferation. In vivo methods include a rat anaphylaxis model, guinea pig Schultz-Dale reaction, and passive cutaneous anaphylaxis in rats. One method involves sensitizing rats with ovalbumin, then challenging them to induce shock, which can be counteracted by test drugs. Another involves sensitizing guinea pigs to egg albumin to study contractions in response to ovalbumin.
1. The document discusses various models used to study Alzheimer's disease, including both in vitro and in vivo models. It describes assays such as inhibitory avoidance, step-down avoidance, and scopolamine-induced amnesia in mice that are used to test drugs for improving memory and cognition.
2. The pathological hallmarks of Alzheimer's disease involve extracellular amyloid plaques, neurofibrillary tangles, and loss of cortical cholinergic neurons. Several genetic models have also been developed to study the disease.
3. A variety of screening models are used to evaluate potential pharmacological treatments for Alzheimer's disease and assess their ability to inhibit acetylcholinesterase activity, affect nicotinic receptors, or antagonize
Preclinical Screening for Neurodegenerative Disease (Multiple Sclerosis)Drx Burade
This file includes introduction to multiple sclerosis (MS) , their sign and symptoms , types of multiple sclerosis, pathophysiology of MS , again this includes the medication that are used to treat MS , & the last point is the Preclinical Screening models or methods for multiple sclerosis . Preclinical Screening models includes in vivo and in vitro models
Screening model of antidiarrheal activity Presented by ABDUL HAMEEDAbdul Hameed
This document presents an overview of a screening model used to evaluate the anti-diarrheal properties of the petroleum ether extract of Swietenia macrophylla seeds. The screening model involves testing the extract on several in vivo models in rats, including castor oil-induced diarrhea to test the effects on defecation rate and stool consistency, gastrointestinal motility tests using charcoal meals, castor oil-induced enteropooling to measure intestinal fluid accumulation, and magnesium sulfate-induced diarrhea. The extract is tested at different doses and compared to standard anti-diarrheal drugs to validate the traditional use of the plant for treating diarrhea.
This document discusses various methods for screening anti-diabetic drugs, including both in vivo and in vitro models. For in vivo models, it describes methods for inducing insulin-dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM) in animals through chemical and surgical means. It also discusses normoglycemic animal models and isolated tissue assays to study insulin activity without inducing diabetes. A wide range of screening techniques are provided to evaluate potential anti-diabetic compounds' effects on glucose regulation, insulin secretion, and insulin sensitivity.
Cns stimulants and depressants screening modelsDRASHTI PATEL
This document discusses methods for screening central nervous system (CNS) stimulants and depressants. It begins by defining the CNS and its major components. It then describes various CNS neurotransmitters and what qualifies as a CNS stimulant or depressant. The document outlines several behavioral tests used to evaluate CNS stimulation and depression in animals, including photoactometer testing, forced swim testing, and benzodiazepine-induced sleeping time. It also classifies common CNS stimulants and depressants and reviews in vivo and in vitro evaluation methods.
Preclinical evaluation of anti-epileptic drugs involves testing in various animal models of seizures. Common models include electrically or chemically induced seizures using maximal electroshock, pentylenetetrazol, picrotoxin, or strychnine administration. The effects of potential drugs are assessed by changes in seizure threshold, pattern, EEG changes, or incidence. Chronic models involve kindling or post-status epilepticus models to evaluate drugs for spontaneous recurrent seizures. Various in vivo methods detailed assess drug effects on different seizure types and epilepsies.
This document summarizes various preclinical screening methods used to evaluate potential anti-epileptic drugs. It describes several animal models of induced seizures including electroshock seizures, chemical-induced seizures using pentylenetetrazol or picrotoxin. It also discusses genetic models like the totterer mouse that is prone to spontaneous seizures. The key methods are maximal electroshock in mice/rats to test generalized tonic-clonic seizure protection and the pentylenetetrazol test in mice to assess anticonvulsant effects against petit mal-like seizures. These preclinical tests aim to predict potential efficacy of new compounds before clinical trials in humans.
This document discusses various animal models used to study psychosis and screen for antipsychotic drugs. It describes models based on behaviors like aggression in hamsters and cotton rats, catalepsy in rodents, pole climb avoidance in rats, footshock-induced aggression in mice, and brain self-stimulation. The document evaluates the validity and assessment of these models. It also discusses newer hypotheses for the mechanisms of psychosis involving glutamate, serotonin, and acetylcholine receptors in addition to dopamine receptors.
Screening models of antiepileptic and nootropic drugsHimikaRathi
This document provides information on various methods used to screen potential antiepileptic drugs. It discusses in vivo models like maximal electroshock induced seizures in mice, pentylenetetrazol induced convulsions, and strychnine induced convulsions. In vitro methods like receptor binding assays and electrical recordings from brain slices are also covered. Different types of induced seizures and animal models of epilepsy are described. The mechanisms of commonly used proconvulsant drugs like picrotoxin and mechanisms of action of antiepileptic drugs are briefly discussed. Various stages of the kindling model are defined.
This document summarizes screening methods for antiulcer agents, including both in vivo and in vitro methods. It begins with an introduction to peptic ulcers and classifications of antiulcer drugs. In vivo screening methods described include the pylorus ligation model in rats, ethanol-induced gastric ulcer model, water immersion stress model, and indomethacin-induced ulcer model. The key in vitro screening method discussed is the H+/K+-ATPase inhibition assay to measure inhibition of proton pump activity. The document provides details of procedures and evaluations for each screening model. It concludes with references for further information.
Invivo screening methods for anti inflammatory agentsSravani Ganti
This document describes various in vivo screening methods used to test potential anti-inflammatory agents. It discusses acute, subacute, and chronic inflammation phases and associated screening methods. Methods described include carrageenan-induced paw edema in rats, croton-oil induced ear edema in mice, oxazolone induced ear edema in mice, UV erythema in guinea pigs, pleurisy test, granuloma pouch technique, and vascular permeability test. Each method involves inducing inflammation and measuring the ability of test compounds to reduce inflammatory responses like edema formation compared to control groups.
This document summarizes methods for screening sympathomimetic and sympatholytic drugs. Sympathomimetics mimic epinephrine and stimulate the sympathetic nervous system, while sympatholytics block these effects. Screening methods include in vivo tests using cat spleens or measuring nictitating membrane prolapse in cats. In vitro tests involve measuring contractions of rabbit pulmonary arteries, rat vas deferens, or cat spleen strips in response to drugs. These assays allow evaluating sympatholytic potency by assessing the ability of test drugs to reduce contractions caused by agonists like epinephrine and norepinephrine.
This document summarizes screening methods for evaluating potential anti-inflammatory drugs. It discusses the inflammatory response and various animal models used to test drug candidates, including carrageenan-induced paw edema, cotton pellet-induced granuloma, and UVB-induced erythema in guinea pigs. Several in vitro assays are also described, such as measuring COX inhibition and evaluating the ability of drugs to block mast cell degranulation and platelet-neutrophil adhesion. The goal of these screening methods is to effectively identify drug candidates that can target different phases and components of the inflammatory process.
This document summarizes screening methods for evaluating the antipyretic (fever-reducing) effects of drugs in animal models. It describes using the Brewer's yeast suspension method to induce fever in rats and rabbits, and then testing potential antipyretic drugs. Key points:
1) Drugs are given to fevered animals and temperatures recorded at intervals to see if drugs lower elevated body temperatures compared to controls.
2) Studies summarized evaluated antipyretic effects of extracts from Bauhinia racemosa and Gracilaria corticata seaweed in rats. Both produced significant antipyretic activity.
3) The rabbit model uses bacterial lipopolysaccharides to induce fever and tests
This document discusses various in vitro and in vivo models for screening diuretic agents. It describes the Lipschitz test for evaluating diuretic activity in rats by measuring urine excretion and sodium content compared to a urea control. It also discusses methods to evaluate saluretic activity in rats by analyzing urine electrolytes and ratios. Clearance methods to assess renal function and site of action are described using conscious dogs under water diuresis and hydropenia conditions. The stop flow technique is explained to study transport along the nephron by clamping the ureter and collecting sequential urine samples.
The document discusses various methods for screening hepatoprotective agents. It describes in vitro models using primary hepatocyte cell culture, hepatic stellate cell culture, and Kupffer cell culture. It also describes several in vivo models including chemically-induced hepatotoxicity using carbon tetrachloride in rats, drug-induced hepatotoxicity using paracetamol in rats, and bile duct ligation in rats. A variety of parameters are measured in these models to evaluate hepatoprotective effects such as liver enzymes, bilirubin levels, hydroxyproline levels, and histopathological analysis of liver tissue.
Screening of ANTIFERTILITY AGENTS and APHRODISIACSHimaniTailor
This document discusses evaluation and screening models for antifertility and aphrodisiac agents. It describes various in vivo and in vitro methods used to test potential antifertility drugs in females, including tests for anti-ovulatory activity like HCG-induced ovulation in rats and cupric acetate-induced ovulation in rabbits. It also discusses screening methods for assessing progestational and oestrogenic activity. For aphrodisiacs, it covers mechanisms of action and potential agents like sildenafil citrate and testosterone, as well as guidelines for conducting experiments on sexual behavior in rats.
Preclinical Screening of Antiasthmatic DrugsShubham Kolge
Bronchial asthma is characterized by both bronchoconstriction and airway inflammation which leads to bronchial hyperresponsiveness to various stimuli. Different mediators are implicated in asthma. As the precise etiology is not known and multiple biochemical processes are triggered by different causative factors, it is difficult to have a single drug which can effectively and simultaneously act upon different mediators. This led to an intense search for potent and safe antiasthmatic drugs. This presentation intends to compile different screening methods for the evaluation of new candidate drugs with potential for the treatment of asthma. These include in vitro, in vivo, receptor binding and enzymatic methods.
This document summarizes screening methods for potential antiparkinson agents. It describes several in vivo and in vitro models used to test compounds. The key in vivo models discussed are:
1. Tremorine and oxotremorine antagonism in mice, which tests a compound's ability to reduce tremors induced by these muscarinic agonists.
2. The MPTP model in monkeys and mice, which uses MPTP to damage dopaminergic neurons and induce Parkinson's-like symptoms that can be reversed or reduced by test compounds.
3. Reserpine antagonism in rats, which tests if a compound can reduce sedation and motor impairment caused by reserpine depletion of cate
The document describes several in vitro and in vivo methods used to study anti-allergic and anti-inflammatory drugs. In vitro methods include inhibition of histamine release from mast cells and inhibition of T cell proliferation. In vivo methods include a rat anaphylaxis model, guinea pig Schultz-Dale reaction, and passive cutaneous anaphylaxis in rats. One method involves sensitizing rats with ovalbumin, then challenging them to induce shock, which can be counteracted by test drugs. Another involves sensitizing guinea pigs to egg albumin to study contractions in response to ovalbumin.
1. The document discusses various models used to study Alzheimer's disease, including both in vitro and in vivo models. It describes assays such as inhibitory avoidance, step-down avoidance, and scopolamine-induced amnesia in mice that are used to test drugs for improving memory and cognition.
2. The pathological hallmarks of Alzheimer's disease involve extracellular amyloid plaques, neurofibrillary tangles, and loss of cortical cholinergic neurons. Several genetic models have also been developed to study the disease.
3. A variety of screening models are used to evaluate potential pharmacological treatments for Alzheimer's disease and assess their ability to inhibit acetylcholinesterase activity, affect nicotinic receptors, or antagonize
Preclinical Screening for Neurodegenerative Disease (Multiple Sclerosis)Drx Burade
This file includes introduction to multiple sclerosis (MS) , their sign and symptoms , types of multiple sclerosis, pathophysiology of MS , again this includes the medication that are used to treat MS , & the last point is the Preclinical Screening models or methods for multiple sclerosis . Preclinical Screening models includes in vivo and in vitro models
Screening model of antidiarrheal activity Presented by ABDUL HAMEEDAbdul Hameed
This document presents an overview of a screening model used to evaluate the anti-diarrheal properties of the petroleum ether extract of Swietenia macrophylla seeds. The screening model involves testing the extract on several in vivo models in rats, including castor oil-induced diarrhea to test the effects on defecation rate and stool consistency, gastrointestinal motility tests using charcoal meals, castor oil-induced enteropooling to measure intestinal fluid accumulation, and magnesium sulfate-induced diarrhea. The extract is tested at different doses and compared to standard anti-diarrheal drugs to validate the traditional use of the plant for treating diarrhea.
This document discusses various methods for screening anti-diabetic drugs, including both in vivo and in vitro models. For in vivo models, it describes methods for inducing insulin-dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM) in animals through chemical and surgical means. It also discusses normoglycemic animal models and isolated tissue assays to study insulin activity without inducing diabetes. A wide range of screening techniques are provided to evaluate potential anti-diabetic compounds' effects on glucose regulation, insulin secretion, and insulin sensitivity.
Cns stimulants and depressants screening modelsDRASHTI PATEL
This document discusses methods for screening central nervous system (CNS) stimulants and depressants. It begins by defining the CNS and its major components. It then describes various CNS neurotransmitters and what qualifies as a CNS stimulant or depressant. The document outlines several behavioral tests used to evaluate CNS stimulation and depression in animals, including photoactometer testing, forced swim testing, and benzodiazepine-induced sleeping time. It also classifies common CNS stimulants and depressants and reviews in vivo and in vitro evaluation methods.
Preclinical evaluation of anti-epileptic drugs involves testing in various animal models of seizures. Common models include electrically or chemically induced seizures using maximal electroshock, pentylenetetrazol, picrotoxin, or strychnine administration. The effects of potential drugs are assessed by changes in seizure threshold, pattern, EEG changes, or incidence. Chronic models involve kindling or post-status epilepticus models to evaluate drugs for spontaneous recurrent seizures. Various in vivo methods detailed assess drug effects on different seizure types and epilepsies.
This document summarizes various preclinical screening methods used to evaluate potential anti-epileptic drugs. It describes several animal models of induced seizures including electroshock seizures, chemical-induced seizures using pentylenetetrazol or picrotoxin. It also discusses genetic models like the totterer mouse that is prone to spontaneous seizures. The key methods are maximal electroshock in mice/rats to test generalized tonic-clonic seizure protection and the pentylenetetrazol test in mice to assess anticonvulsant effects against petit mal-like seizures. These preclinical tests aim to predict potential efficacy of new compounds before clinical trials in humans.
This document discusses various animal models used to study psychosis and screen for antipsychotic drugs. It describes models based on behaviors like aggression in hamsters and cotton rats, catalepsy in rodents, pole climb avoidance in rats, footshock-induced aggression in mice, and brain self-stimulation. The document evaluates the validity and assessment of these models. It also discusses newer hypotheses for the mechanisms of psychosis involving glutamate, serotonin, and acetylcholine receptors in addition to dopamine receptors.
Screening models of antiepileptic and nootropic drugsHimikaRathi
This document provides information on various methods used to screen potential antiepileptic drugs. It discusses in vivo models like maximal electroshock induced seizures in mice, pentylenetetrazol induced convulsions, and strychnine induced convulsions. In vitro methods like receptor binding assays and electrical recordings from brain slices are also covered. Different types of induced seizures and animal models of epilepsy are described. The mechanisms of commonly used proconvulsant drugs like picrotoxin and mechanisms of action of antiepileptic drugs are briefly discussed. Various stages of the kindling model are defined.
This document summarizes screening methods for antiulcer agents, including both in vivo and in vitro methods. It begins with an introduction to peptic ulcers and classifications of antiulcer drugs. In vivo screening methods described include the pylorus ligation model in rats, ethanol-induced gastric ulcer model, water immersion stress model, and indomethacin-induced ulcer model. The key in vitro screening method discussed is the H+/K+-ATPase inhibition assay to measure inhibition of proton pump activity. The document provides details of procedures and evaluations for each screening model. It concludes with references for further information.
Invivo screening methods for anti inflammatory agentsSravani Ganti
This document describes various in vivo screening methods used to test potential anti-inflammatory agents. It discusses acute, subacute, and chronic inflammation phases and associated screening methods. Methods described include carrageenan-induced paw edema in rats, croton-oil induced ear edema in mice, oxazolone induced ear edema in mice, UV erythema in guinea pigs, pleurisy test, granuloma pouch technique, and vascular permeability test. Each method involves inducing inflammation and measuring the ability of test compounds to reduce inflammatory responses like edema formation compared to control groups.
This document summarizes methods for screening sympathomimetic and sympatholytic drugs. Sympathomimetics mimic epinephrine and stimulate the sympathetic nervous system, while sympatholytics block these effects. Screening methods include in vivo tests using cat spleens or measuring nictitating membrane prolapse in cats. In vitro tests involve measuring contractions of rabbit pulmonary arteries, rat vas deferens, or cat spleen strips in response to drugs. These assays allow evaluating sympatholytic potency by assessing the ability of test drugs to reduce contractions caused by agonists like epinephrine and norepinephrine.
This document summarizes screening methods for evaluating potential anti-inflammatory drugs. It discusses the inflammatory response and various animal models used to test drug candidates, including carrageenan-induced paw edema, cotton pellet-induced granuloma, and UVB-induced erythema in guinea pigs. Several in vitro assays are also described, such as measuring COX inhibition and evaluating the ability of drugs to block mast cell degranulation and platelet-neutrophil adhesion. The goal of these screening methods is to effectively identify drug candidates that can target different phases and components of the inflammatory process.
This document summarizes screening methods for evaluating the antipyretic (fever-reducing) effects of drugs in animal models. It describes using the Brewer's yeast suspension method to induce fever in rats and rabbits, and then testing potential antipyretic drugs. Key points:
1) Drugs are given to fevered animals and temperatures recorded at intervals to see if drugs lower elevated body temperatures compared to controls.
2) Studies summarized evaluated antipyretic effects of extracts from Bauhinia racemosa and Gracilaria corticata seaweed in rats. Both produced significant antipyretic activity.
3) The rabbit model uses bacterial lipopolysaccharides to induce fever and tests
This document discusses various in vitro and in vivo models for screening diuretic agents. It describes the Lipschitz test for evaluating diuretic activity in rats by measuring urine excretion and sodium content compared to a urea control. It also discusses methods to evaluate saluretic activity in rats by analyzing urine electrolytes and ratios. Clearance methods to assess renal function and site of action are described using conscious dogs under water diuresis and hydropenia conditions. The stop flow technique is explained to study transport along the nephron by clamping the ureter and collecting sequential urine samples.
The document discusses various methods for screening hepatoprotective agents. It describes in vitro models using primary hepatocyte cell culture, hepatic stellate cell culture, and Kupffer cell culture. It also describes several in vivo models including chemically-induced hepatotoxicity using carbon tetrachloride in rats, drug-induced hepatotoxicity using paracetamol in rats, and bile duct ligation in rats. A variety of parameters are measured in these models to evaluate hepatoprotective effects such as liver enzymes, bilirubin levels, hydroxyproline levels, and histopathological analysis of liver tissue.
Evaluation of hepatoprotective agents - Hemant KanaseHemant Kanase
1. Introduction
2. Hepatotoxicity: Mechanism
3. Therapeutic strategies available – their limitations
4. In vivo models of liver damage
- Non-invasive model
a. Chemically induced hepatotoxicity
b. Drug-induced hepatotoxicity
c. Radiation-induced hepatotoxicity
d. Metal-induced hepatotoxicity
e. Diet-induced hepatotoxicity
Models of Acute Hepatitis
Models of chronic hepatitis
Models of fibrosis
Models of cholestasis
Models of steatosis
4. Problems faced with animal studies
5. In vitro models of liver damage
6. Advantages and disadvantages of in vitro models
7. Parameters of evaluation
8. Clinical Assessment
Kaempferol increases levels of coenzyme Q in kidney cells and serves as a biosynthetic ring precursor
Complete study available in Free Radical Biology and Medicine. 2017 Sep;110:176-187.
doi: 10.1016/j.freeradbiomed.2017.06.006. Epub 2017 Jun 9.
This document summarizes a study examining the anti-proliferative effects of Arisaema intermedium lectin (AIL) on human colon cancer cells. AIL was purified from Arisaema intermedium tubers and its effects were tested on HCT-15 colon cancer cells. MTT assays showed AIL inhibited the growth of HCT-15 cells in a dose-dependent manner, with 53% inhibition at 100 μg/mL AIL. Further experiments found AIL treatment led to DNA fragmentation, changes in nucleic acid content, cell morphology changes, and decreased cell viability, indicating AIL induces apoptosis in HCT-15 cells. The results suggest AIL has anti-cancer properties and works through an apoptotic
The document discusses various methods for screening hepatoprotective drugs. It describes in vitro models using primary hepatocyte cultures, hepatic stellate cell cultures, and assays measuring proline hydroxylation inhibition. In vivo models inducing liver injury in rats are also outlined, including models using Long Evans Cinnamon rats, hepatic ischemia, allyl alcohol, carbon tetrachloride, and galactosamine. The goal of these screening methods is to evaluate potential drug candidates for protecting against liver toxicity and damage.
This document provides information on plant poisoning, specifically mushroom poisoning and mycotoxins, as well as clinical symptoms and management of acute poisoning from caustics such as inorganic acids and alkalis. It discusses mushroom poisoning in detail, including the types of toxic mushrooms, toxins produced, clinical features, diagnosis and treatment. It also covers mycotoxins commonly produced by fungi, including aflatoxins and trichothecenes. The document concludes by describing sulfuric acid and nitric acid poisoning, their uses, effects, diagnosis and emergency treatment.
This document describes preclinical screening models used to evaluate antihyperlipidemic drugs. It discusses in vivo models like triton-induced hyperlipidemia in rats and cholesterol-diet induced atherosclerosis in rabbits. It also discusses in vitro models like inhibition of the enzyme HMG-CoA reductase and ACAT inhibitory activity assays. The purpose of these preclinical models is to test potential lipid-lowering drugs for their ability to reduce elevated lipid levels or inhibit key enzymes prior to clinical trials.
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
All manuscripts are subject to rapid peer review. Those of high quality (not previously published and not under consideration for publication in another journal) will be published without delay.
Nanjing 2 2013 Lecture "Nutrigenomics part 2" From healthy to too much: The r...Norwich Research Park
1. The lecture discusses the role of the small intestine in metabolic flexibility and how its function is affected by dietary factors like saturated and unsaturated fats. Microarray analysis showed high-fat diets significantly impact gene expression in the small intestine, especially related to lipid metabolism.
2. Unsaturated fats are more efficiently taken up in the small intestine by activating nutrient sensing pathways like PPARs, helping prevent early pathology from a high-fat diet. Saturated fats stimulate obesity, hepatic steatosis, and affect the gut microbiota composition.
3. A systems genetics study of mouse strains found a genetically determined set point for obesity. Certain strains showed robust, strain-specific changes in obesity traits from a
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screening models for hepatoprotective agents slide share
1. S C R E E N I N G M O D E L S O F
H E P A T O P R O T E C T I V E D R U G S
Presented by Under the Guidance of
P N.Savitha Mrs.V.Rajani M.Pharm(Ph.D)
M.Pharmacy 1yr1 st semester Associate Professor
Dept of Pharmacology Dept.of Pharmacology
SKU COLLEGE OF PHARMACEUTICAL SCIENCES, S.K.UNIVERSITY,
ANANTAPURAMU
2. INTRODUCTION
Liver is large organ that found in vertebrates which
detoxifies various matabolites ,synthesizes
proteins,produces biochemicals necessary for digestion.
It has main role in maintenance,performance and
regulating homeostasis of body.
Liver produces bile,a compound needed to digest fat
and to absorb vit A,D,E,K.
Liver involved with biochemical pathways to
growth,fight against disease,nutrient supply,energy
provision& reproduction.
3. HEPATO TOXICITY
Hepatotoxicity is the injury or liver damage
caused by exposure to drugs.
The hepatic injury can be classified into:
Hepatocellular
Cholestatic
Mixed
It is caused by increase in alanine,
aminotransferases, alkaline phosphates
than upper limit of normal.
Hepatotoxicity caused majorly by drugs,
autoimmune disorders, and infection like viral
hepatitis.
4. MARKERS OF HEPATOTOXICITY
1)Aspartate serum transferase(AST)
2)Alanine amino transferase(ALT)
3)Alkaline phosphatase(APP)
4)Lactate dehydrogenase(LDH)
5)Total bilirubin(TB)
6)Total protein(TP)
7)Total triglycerides(TG)
8) γ -Glutamyl transferase(GGT)
M EC H A NI S M O F ACTI ON
Oxidation in liver produce reactive free oxygen
radicles.These cause hepatotoxicity because of
release of free radicles cause apoptosis in liver
reduces Glutothiolevels.
5. LIST O F HEPATOPROTECTIVE
AGENTS
N-Acetylcysteine
Pencillamine
Cardiotropin 1
S-Adenosyl Methionine
Herbal medications eg:Silymarine
Antioxidants
eg: Vitamins,
Glutathione,
Melatonin,
β Carotene.
6. Anti tubercular
drugs
• Rifampacin
• Isoniazid
• Pyrazinamide
• Ethionamide
• Levofloxacin
• Thioacetazone
• Cycloserine
NSAIDS
• Paracetamol
• Diclofenac
• Ibuprofen
• Indomethacin
• Oxicam groups
Antimicrobials
• Dapsone
• Ketoconazole
• Sulphonamides
• Erythromycin
• Azithromycin
• Streptomycin
• Anti retrovirals
D R U G S INDUCED LIV ER INJUR Y
8. SCREENING METHODS
1) Inhibition of Proline hydroxylation.
2) Influence on collagen synthesis in Human skin fibroblasts.
3) Influence on collagen synthesis in Chicken Calvaria.
4) Liver Cirrhosis and Necrosis.
5) Primary hepatocyte Cell culture.
6) Hepatic stellate cell culture(HSC).
7) Kuffer Cell Culture.
8) Liver Slice System.
9. 1. Bile duct ligation induced Liver fibrosis in Rats.
2. CCL4 Induced Liver fibrosis in Rats.
3. Allyl alcohol induced Liver necrosis in rats.
4. Galactosamine induced Liver necrosis.
5. Temporary Hepatic ischemia.
6. Hepatitis in Long-Evans Cinnamon Rats.
7. Model for direct Transhepatic studies in Dogs.
8. Thioacetamide induced Liver necrosis.
9. Paracetomol induced liver necrosis.
10. Rifampacin+Isoniazid induced Hepatotoxicity in rats.
11. Dimethylnitrosamine induced fibrosis & necrosis.
10. INVITRO METHOD
1) Hepatic stellate cell culture(HSC)
Purpose:To asess the antifibrotic efficacy of exp drugs,these primarly cultured
cells are useful in assesing specific effects on HSC activities.
Procedure:HSC are isolated from the livers of normal rats weighing at least
500g in order to achieve good separation from the other hepatic cells.The liver
is digested with pronase,cillagenase,Dnase by insitu perfusion
After several centrifugation steps,cell suspension is subjected to a Nycodenz
gradient to collect the HSC on top of the Nycodenz layer.
The separation is based on low density of HSC as compared to other liver cells,
as a consequence of their high cellelar lipid content.
About 5 mice have to be used at a same time to yield more amount of HSC from
liver.
Isolated cells are cultured in DMEM containing 10% FCS,100U/ml
pencillin,100mg/ml streptomycin.
Evaluation:After 10-14 days in culture,the cells display an activated
phenotype as assessed by light microscopy & acquire the presence of alpha
smooth muscle actin.
11. 2) Liver slice system
Purpose:It developed to assess effects of antifibrotic drugs in liver slice
preaparation.
Procedure:Liver slices are prepared as follows:
Livers are excised from rats & stored.Slices were prepared in Krebs-
Henseleit buffer saturated with95% O2, 5%CO2 & containing 25mM
glucose,25mM NaHCO3,10mM hepes using Krumdieck tissue slicer.
To equillibrate the tissue,slices are preincubated for 1h in Williams medium
E-Glutamax with 25mM glucose,50mg/ml gentamicin under carbogen
atmosphere at 37ºC in 6 well culture plates while gently shaken.
Again slices transferred to fresh medium & incubated.
Evaluation:.HSC & extracellular matrix components & resident hepatic cells
which allow testing of Multicellular interactions.
Advantages:
1. Easily prepared from normal, fibrotic,cirrhotic tissue.
2. This system easily allows drug testing in human liver material.
Disadvantages:
1. This method is limited time period of study.
2. Absence of blood flow through the slice.
12. 3) Inhibition of proline hydroxylation
Purpose:The thermal stability of triple helix of collagenase is depend on
intramolecular H bond synthesized by the enzyme prolyl 4 hydroxylase.
Procedure:
Reaction volume of 1ml contains
50mM Tris buffer(ph-7.5),10-100mM 2oxo glutarate, 1-50mMFeso4,
1mMAscorbate, 10-100mg(ProPro-Gly)10, 0.1mg catalase, 2mg bovine serum
albumin, 100mmdithiotretiol, 0.2mgenzyme & inhibitors.
After incubation at37ºC for 30 min, the generated C02 is trapped and
determined.
Evaluation:
Inhibition modes are determined by plotting 1/v versus 1/c of variable
substrate(Lineweaver burk plot).
The Ki values are derived from secondary transformation(slopes or
intercepts).
The lines of best fit for primary & secondary transformations are calculated
using the method of ‘least square’.
13. 4) Influence on collagen synthesis in human skin fibroblasts
Purpose: Secretion of collagen by fibroblasts & other cells capable of
synthesizing extracellular matrix is dependent on the hydroxylation of proline
residues by propyl 4-hydroxylase.
Procedure: Culture of human skin fibroblasts are preincubated for 24hr at37ºC
in Dulbeccos medium supplemented with 50mg/ml sodium ascorbate,60mg/ml
3-aminopropionitrile,10U/ml pencillin G.
The cells are then exposed to potential inhibitor at various concentration for 20
min,followed by addition of radioactive(C14) 2m proline/ml.
The incubation is continued for 5h at 37ºC. Then the cells are separated from
the medium.
After removal of proline,the proteins from medium, the cells are hydrolysed &
the hydroxyproline content is determined by aminoacids analysis.
The total incorporation of radioactivity serves as marker for protein synthesis.
Evaluation: Proline incorporation is expressed as % of control Radioactivity.
Formula: Hyp/Pro Sample
= *100
Hyp/Pro Control
14. 5) Influence on collagen synthesis in chicken calvaria
Purpose:To find fibrosuppresive agents for therapeutic use,drugs which
converted intracellularly to the active agent.Proinhibitors which are cleaved
hydrolytically can suppress collagen synthesis in chicken calvaria.
Procedure:
Calvaria are removed from chicken embroys,age 15 days&washed.They are
tranferred to pyrex tubes containing medium supplemented with 2mM
glutamine,6mCi radioactive proline&various conc of inhibitors.
The samples are incubated.Calvaria removed,washed,pooled with incubation
medium.BSA& phenyl methyl sulphonyl flouride are added.
The calvaria are extracted for 16h with 25ml of acetic acid.Aliquots are
withdrawn for SDS-PAGE & the triple helix stability assay performed.
By using remaining material, hydroxyproline content is determined.
To study the degree of collagen hydroxylation&proportion of collagen
biosynthesis,calvaria are incubated in presence of 10mCi and 2mCi
radioactive proline/ml for 3h.
After lyophilization,aliqouts of media&calvaria samples are digested with
collagenase.
15. The degree of hydroxylation is calculated from the 3H/C₁₄ ratio in digested
material.
The amount of collagen as a proportion of total protein synthesis is
determined by :
The relation of collagenase degradable v/s collagenase resistant activity.
Evaluation:
IC50 values of hydroxyproline synthesis are read graphically from
concentration response curves.
Total protein synthesis is estimated as the incorporation of proline;the
mean±standard deviation is calculated from 4 samples.
16. 6) Liver Cirrhosis & Necrosis
Purpose & Rationale:
Excessive formation of connective tissue with collagen over production
reduces hepatic blood flow.
Collagen is formed as a response to chronic injury.The collagenous fibers
consist of triple helical molecules.Their formation depends on the presence of
hydrogen bonds.
If the number of hydrogen bonds is reduced,the resulting collagen can not
form triple helix & is degraded instead of being deposited in the extracellular
matrix.
The aim of fibrosuppressive compounds is to reduce only the excessive
formation of insoluble collagen.
Evaluation:
Fibrosuppressive effects by inhibition of proline hydroxylation can be
screened invitro method.
But the desired organ specificity has to be tested in invivo models.
17. 7) Kuffer cell culture
Isolation:
Kuffer cells are isolated from the liver by perfusion of liver with pronase
followed by differential centrifugation.
The isolated cells are isolated are maintained in culture where their
phagocytic properties are retained.
On exposure of cells phagocytic stimuli like zymosan particles, ther is
increased O2 consumption & superoxide production.
The inhibitory effects of various drugs on kuffer cells are tested in the
invitro cultures.
18. 8) Primary Hepatocyte cell culture
Fresh hepatocyte preparations & primary cultured hepatocytes are used.
Common method:
Isolation of hepatocytes by perfusion of liver with collagenase or utilization
of primary cultured hepatocytes.
Determination of viability of the hepatocytes.
Incubation of cell culture with hepatotoxin with or without drug test drug.
Determination of activity of transaminase released into medium by the
hepatocytes.
Hepatotoxins include:CCL4
D-galactosamine
Tert butyl hydroperoxide
Ethanol.
19. INVIVO METHOD
1) CCl4 induced liver fibrosis in rats
Purpose:Chronic administration of CCl4 to rats liver fibrosis with severe
disturbances of hepatic function.
Procedure: Groups of 20 wistar rats weighing 100-150g.
CCL4 Dissolved in olive oil (1:1) ,given orally twice a week of 1mg/kg-over a
period of 8 weeks.
Animals are kept in standard conditions:22ºC temp,std diet,water ad libitum
20 rats Contol-olive oil,
20 rats Carbon tetrachloride only
20 rats ccl4 along with various doses of test drug twice a
week ,at weekend ingle dose given.
The animals are weighed every week,after 8 weeks animals are sacrified
using anaesthetic ether.
In serum,parameters determined include:
Total bilirubin
Total bile acids
7S fragment of typeⅣcollagen
Procollagen Ⅲ N peptide.
20. Organs for determination of hydroxyproline are:
Liver
Kidney
Aortic wall
Tendons
specimens of organs are weighed & completely hydrolysed in 6N
HCL.Hydroxyproline is measured by HPLC& expressed in mg/mg wet weight
of organs.
Histology:3 to 5 pieces of 1g liver fixed in formalin& carnoy solution
3to5 sections of each liver are embedded,ct,stained with Azocarmine aniline
blue & evaluted for development of fibrosis using scores:
0-Normal liver history
Ⅰ-Tiny & short septa of connective tissue
ⅠⅠ-Large septa of connective tissue
Ⅲ-Nodular transformation of liver
Ⅳ-Excessive formation &deposition of connective tissue
Evaluation:
For detection of significant differences,the unpaired t-test used.
For comparison of scores in histological evalution ,chi-square test used.
21.
22. 2) Allyl alcohol induced liver necrosis in rats
Purpose:Allyl alcohol induces focal liver necrosis in rats, which can be
prevented by treatment with antibiotics.
Procedure:Female wistar rats(150-200g)are fasted overnight
1 day-morning test drug given orally/Ip,
after 1h 0.4ml/kg of 1% Allyl alcohol soln orally.
2 day-again test drug given.
3 day-animal sacrified,liver is removed.
Evaluation:
The parietal sides of liver are checked in stereomicroscope in
25Xmagnification.
Focal necrosis is observed as white green/yellowish haemorrhagic area.
Using contol & treatment group,mean of Necrosis index is calculated &
compared with students t-test.
The protective effect is expressed as% decrease of Necrosis index v/s controls.
23. 3) Bile duct ligation induced liver fibrosis in rats
Purpose:Bile duct ligation in rats induces Liver fibrosis which can be
evaluted by histological means & determination of serum collagen
parameters.
Procedure:
Male sprague dawley rats(250g) anesthetized with ketamine ,xylazine
Laparactomy is performed under aseptic condition.
Expose the common bile duct,from hilum of liver to opening into
duodenum&duct is embedded for greater part of its length in
pancreas,which opens into it by numerous small duct.
A blunt needle is passed under duct,stripping the panceas away& duct is
divided b/w double ligatures of thread.peritonium,muscle layers,skin
wounds are closed by stiching.
Groups of 5-10 animals receive test compound in various doses twice a day
over 6 weeks & sacrified.
24. Evaluation:
In serum,parameters to be determined are:
Total bilirubin,
Total bile acid,
7S fragment of typeⅣcollagen,
ProcollagenⅢ N peptide.
The liver is used for Histological studies & Hydroxyproline determinations.
Contol animals show excessive bile duct proliferation&formation of fibrous
septa.
25. 4) Galactosamine induced liver Necrosis
Purpose:Single dose or repeated dose of D-galactosamine cause acute hepatic
necrosis. Prolonged administration leads to cirrhosis.
Procedure:
Male wistar rats weighing 150-200g are used.
For induction of Acute hepatotoxicity:Divided doses of 100-400mg/kg GS is
given in Ip route for 1day.
For induction of liver cirrhosis:500mg/kg Galactosamine is given ip
route,thrice a week over 1-3 months.
Potential protective drugs are given oral route with food ,everyday.
Rats are sacrified and the livers obtained by autopsy.
Evaluation:
The livers are evaluted by light microscopy&immunohistology using
antibodies against macrophages,lymphocytes, extracellular matrix
components:e.g:laminin, fabronectin, desmin&collagen typesⅠ,Ⅲ&Ⅳ.
Serum enzyme activities,such as GOT & GPT determined.
The extent of liver necrosis&immunoreactivity is graded on scale as:
0-Absent
1-Trace
2-Weak
3-Moderate
4-Strong
26. 5) Thioacetamide induced hepatotoxicity in rats
Purpose:Thioacetamide acts as hepatocarcinogen & hepatotoxicant.This
action is ,mediated by formation of S-oxide,which covalently binds with liver
cell macromolecules like protein,nucleic acid,lipids which increases
intracellular Ca+ concentration & causes necrosis.
Procedure:
Wistar/sprague dawley rats weighing 200-250g are used.
They are maintained on a standard chow diet ,water &libitum at 23ºC
under 12h dark/12h light.
Animals are starved for 18h,before experiment starts.
Hepatotoxicity is induced by thioacetamide 200mg/kg oral or 100mg/kg S.C
route thrice weekly over 8 weeks.
Animal is sacrified,liver is separated&serum collection.
Evaluation:
Serum is used for determination of Aminotransferase marker.
Liver is used for Histopathological studies.
27. 6) Paracetamol induced liver damage in rats
Purpose:
Paracetamol in higher dose induce Hepatic damage.
It gets metabolized to N-acetyl p benzoquinone imine by cytp450 enzyme
which results in oxidative stress causing liver glutathione & glycogen
depletion.
Procedure:
Wistar rats of either sex weighing 150-200 g are used.
Paracetamol 2g/kg body wt is administered orally as single dose.
Test drug- given for 6days in (oral).
Inducing agent-Paracetamol given on 7th day.
Animals are sacrified after 24hr.Blood is collected.Liver is separated.
Evaluation:
Blood/serum is used for biochemical analysis.
Liver is used for Histopathological stidies.
28. 7) Rifampicin+Isoniazid induced Hepatotoxicity in rats
Purpose:
Rifampicin&Isoniazid are used together as 1st line antitubercular drugs.
In higher doses,they show toxic effects to liver of rats.
Procedure:
Wistar/sprague dawley rats of either sex weighing 150-200g are used.
Rifampicin&Isoniazid are given in dose of 50mg/kg body wt each by Ip inj
once daily for 15 days along with test drug.
At the end of experiment rats are sacrified by decapitation.
Evaluation:
Blood/serum is used for biochemical analysis.
Liver is used for Histopathological studies.
29. 8) Dimethylnitrosamine induced liver Fibrosis(DMN)
Purpose:DMN induces liver injury by intiating damage to the hepatocyte.
It is metabolised in hepatocytes by cytP450 to more toxic compounds with
formation of reactive O2 species which leads to lipid peroxidation.
Procedure:
Albino wistar rats of either sex weighing 200-250g are use.
Animlas are maintained in standard Chow diet,water ad libitum at 23ºC.
To induce fibrosis,DMN given in Ip route,dose of 10μl body wt ,thrice a week
for 3weeks.
At end of experiment animals are sacrified.Liver is used for Histopathological studies.
Evaluation:
After giving DMN, haemorrhagic necrosis is evident in centrolobular part (zoneⅢ)of
liver.
Incomplete septa appear after 7 days.Micronodular cirrhosis is developed after 3
weeks treatment with DMN.
Increased no.of HSC & myofibroblasts are found in formed septa.Influx of
inflammatory cells mainly lymphocytes,is noted early.
Advantages:
1. Disease introduction is quite reproducible in the animals.
2. This model is associated with prominent inflammatory reaction.
3. Used to study the transition from cirrhosis to hepatocellular carcinoma&influence of
drugs on this process.
30. 9) Hepatitis in Long-Evans cinnamon rats
Purpose:
To study genetically transmitted fulminat heapatitis&chronic liver
disease.Excessive copper accumulation in the rats liver, making model best
for Wilsons diseasein humans.Chelation therapy/feeding copper deficient diet
can ameliorate symptoms in rats & wilsons disease.
Procedure:
Male long cinnamon rats obtained from commercial breeder.
Groups of 6-10 rats are given different diets based on a 15%purified egg
protein,vitaminds or drugs.
Drugs are applied via minipumps Ip implanted under ether anaesthesia.
The occurrence of jaundice-ears & tail turn yellow,urine becomes bright
orange,staining the fur in lower abdominal region.
Usually jaundice progressively worsens,ending in death of animal within
about week.Incidence of jaundice&mortality v/s time used as parameters.
Evaluation:
Statistics are performed for students T-test,ANOVA,Scheffe F-test for
comparison b/w means.
P-value<0.05 is used as the thresold of significance.
31. 10) Models for Direct Transhepatic studies in Dogs
Purpose:
To study hepatic effects of pancreatic hormone secretion&glucose metabolism.
To study hepatic mechanisms associated with high first pass metabolism&
food interaction of drugs.
To study the insulin balance in dogs that have undergone previous
pancreactomy&islet cell autotransplantation.
Procedure:
Male dogs weighing 20-25kg are anaesthetised by isoflourane inhalation.
Skin interface sites & subcutaneous pockets for placement of catheters are
prepared.
After skin closure the external ends of catheters are sealed.
Then the catheters & flow probes are placed into abdomen retriving them
from subcutaneous pockets.
a.Hepatic artery,Portal venous flow probes inserted.
b.The portal vein&hepatic vein catheters are placed & abdomen is closed.
c. The carotid artery & jugular vein catheters are placed.
Evaluation:
Blood samples are withdrawn from catheters.
Blood flow & Plasma flow is measured by flow probes in hepatic artery &
hepatic portal vein.
Drug conc measured in portal vein,hepatic artery,hepatic vein,right
external jugular vein.
32. 11)Temporary hepatic ischemia
Purpose:
Total hepatic ischemia in rats is produced by placing a ligature around the
hepatic artery,portal vein,bile duct.
Procedure:
Albino rats300-350g are fasted 16h prior to experiment allowed water libitum.
Rats anesthetized with ether,abdominal cavity is opened.
Hepatic artery,portal vein,bile duct are occluded by by placing torniquet
around vessels.BP is measured in femoral artery via catheter.
During ischemic period 0.7ml saline given at 20min intervals for volume
replacement.
At the end of 60min ischemic period,tourniquet is removed to reestablish blood
flow to liver.Abdominal incision closed&Animals receive either saline or drug.
Measurement of Indocyanine green:
In exp animals,femoral artery &vein of each aniamal cannulated.Sodium
heparin(400units) is given in Ip route,animals allowed to awake.
33. Indocyanine geen is given Iv low 5mg/kg & high doses 25mg/kg.Arterial blood
samples are taken at 5,6,8,10,12,15,18 & 20 min later.
Blood samples are mixed with 0.8ml of 1%BSA in saline & centrifuged at 6000
rpm for 20min at 4ºC.
The spectrophotometric absorbance of supernatant is read at 800nm &
finally indocyanin green conc determined from standard curve.
Evaluation:
The t½ of indocyanin green clearance is computed for each animal using
computarised program,which calculates ‘Least Square Line’ of log
indocyanin green v/s time.
Mean Standard errors for each group are compared using Students t-Test.
34. RE F E RE N C E S :
H Gerhard Vogel, Drug discovery & Evalution pharmacological assays,
2nd edition.page no:936-944.
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