Antihypertensive Screening Models, invivo models, invitro models, transgenic models

1. ANTIHYPERTENSIVE SCREENING
MODELS
Noida Institute of Engineering and Technology
(Pharmacy Institute)
Greater Noida
Presented by :-
Vishnu Prabhakar
M.Pharm(Pharmacology)
Submitted to :-
Dr. Saumya Das
Associate Professor
NIET (Pharmacy Institute)
Greater Noida
Credits:- goodhousekeeping.com

2. HYPERTENSION
Hypertension ̶ or elevated blood pressure ̶ is a serious medical condition
that significantly increases the risks of heart, brain, kidney and other diseases.
An estimated 1.28 billion adults aged 30-79 years worldwide have
hypertension, most (two-thirds) living in low- and middle-income countries
An estimated 46% of adults with hypertension are unaware that they have
the condition.
Less than half of adults (42%) with hypertension are diagnosed and treated.
Approximately 1 in 5 adults (21%) with hypertension have it under control.
Hypertension is a major cause of premature death worldwide.
One of the global targets for noncommunicable diseases is to reduce the
prevalence of hypertension by 33% between 2010 and 2030.

3. Blood Pressure Category
Systolic
Blood
Pressure
Diastolic
Blood
Pressure
Normal
Less than
120
and
Less than
80
High Blood Pressure (no other heart
risk factors)
140 or
higher
or
90 or
higher
High Blood Pressure (with other
heart risk factors, according to some
providers)
130 or
higher
or
80 or
higher
Dangerously high blood pressure -
seek medical care right away
180 or
higher
and
120 or
higher
Your blood pressure reading uses these
two numbers. Usually, the systolic
number comes before or above the
diastolic number. For example, 120/80
means a systolic of 120 and a diastolic of
80.
Diastole and systole are two phases of
the cardiac cycle. They occur as the
heart beats, pumping blood through a
system of blood vessels that carry blood
to every part of the body.
Systole occurs when the heart contracts
to pump blood out, and diastole occurs
when the heart relaxes after
contraction.[1]

4. IN-VIVO METHODS
• DEXAMETHASONE INDUCED
HYPERTENSION
• SALT SENSITIVE DAHL RAT
• CHRONIC RENAL HYPERETENSION 1 KIDNEY -1-
CLIP METHOD
• ANGIOTENSIN II ANTAGONISM
Credits:- shutterstock.com

5. DEXAMETHASONE INDUCED HYPERTENSION
The Wistar rats (150-200 g) of either sex were used and each experimental group was comprised of 6 animals.
The rats were housed under standard laboratory conditions (22 ± 2 °C, 12 hours light/dark cycle) with free
access to food (normal pellet diet) and water.
Hypertension was induced by subcutaneous injection of dexamethasone (10 μg/rat/day) in hypertensive rats.
The animals were randomly divided into four groups comprising of six rats per group.
The hypertensive group animals were treated with test drug respectively for 8 weeks.
While systolic blood pressure (SBP) was measured by the tail-cuff method weekly up to 8 weeks.
Body weight, food and water intake of each group animals were measured weekly up to 8 weeks.[2]

6. SALT SENSITIVE DAHL RAT
Sprague-Dawley Rats (250-300gm) are used in this study, they develop fatal hypertension when fed high salt diets.
High salt diet prepared by mixing salt with regular diet and water replaced by 8% NaCl solution.
These rats were feed with these diet and saline solution.
Test group rats are administered the drug orally for 1 month.
Bloood pressure changes are recorded .
After the experiment, the animal both control and test group are sacrificed.
The heart are isolated,the mass,weight of LV & RV is compared and measured.
Upon salt feeding animal BP rises steeply up to 36% , then the ability of the drug to reverse these changes are studied.
Cardiac failure occurs at 4 to 5 months of age in these kinds of rats.

7. CHRONIC RENAL HYPERETENSION
1 KIDNEY -1- CLIP METHOD
Sprague – Dawley Rats (200-300) are anesthetized by Phenobarbitone sodium (100mg/kg) intra
peritoneally.
A flank parallel incision is made in the left lumbar area.
Renal artery is dissected, cleaned and U-shaped silver clip is slipped around near the aorta.
The internal gap b/w the clip is adjusted to 0.25-0.38 nm.
The right kidney is removed after tieing off the renal pedicel.
After 4-5 weeks the BP. is measured and the animals are divided into groups of different doses.
The drug is administered for 3 days
Pressure before and after drug administration ( 3 min ) are recorded.
Percentage reduction in pressure is calculate and compare to the Standard.

8. ANGIOTENSIN II
ANTAGONISM
• Male Sprague-Dawley rats (220-225gm) are selected.
• They are anaesthetized with 60mg/kg of phenobarbitone sodium.
• One carotid artery is cannulated & connected with a Statham transducer
and the BP. is recorded in a polygraph.
• Both the jugular veins are cannulated to administer the test drug.
• Pentolinium (10mg/kg) is injected to block the ganglionic activity.
• At least 5 animals are used for the evaluation of test drug.
• In 10 min interval doses of 0.5,1.0,and 2µg/kg of angiotensin II are
injected to establish the dose response curves.
• After 10 min a continuous infusion is started of the Ang II blocker in a
dose of 10 µg/kg/0.1ml/ml.
• Again, dose of 0.5,1.0 and 2µg/kg of Angiotensin II are injected.
• Intensity and duration of fall in BP. is recorded.
• The result are compared with the known standard drug.

9. IN-VITRO METHODS
L-NAME INDUCED
HYPERTENSION
MONOCROTALINE
INDUCED
HYPERTENSION
Credits:- angilo.edu

10. L-NAME INDUCED HYPERTENSION
• Male Wistar rats and mice of both sexes were used in this method.
• They are exposed to 12 h dark/light cycle , they were fed on normal laboratory diet with free access
to water and food.
• Cardiovascular experiments were carried out on rats aged 12–16 weeks and weighing (250–300gm)
while mice (20–25 gm) with the same age were used for the test.
• Hypertension was induced by L-NAME (40 mg/kg/day, p.o.) for 30 consecutive days, test drug was
given at the same time.
• Systolic blood pressure and heart rate were measured before starting the treatment and at the end of
each week.
• Urinary volume and urinary sodium and potassium contents were quantified before and at days 1, 15
and 30 of the treatment.
• Animal body weight Aorta from treated animals was tested for their sensitivity to noradrenalin and
carbachol.

11. CONTD……
Aorta from normal untreated rats was used to
evaluate the in vitro vascular effect of test .
The heart was removed free of fats and
connective tissues and weighed. The left and the
right ventricles were also dissected and weighed.
L-NAME - NG-nitro-L-arginine methyl ester
hydrochloride [3]

12. MONOCROTALINE INDUCED HYPERTENSION
• Monocrotaline, a pyrrolizidine alkaloids derived from crotaloria spectabillis.
• Sprague – Dawley rats (200-225gm) of either sex were selected.
• Animal are fed with test drug for one week prior to Subcutaneous injection of Monocrotaline 100mg/kg.
• Animals are sacrificed 7 to 14 days later, and their hearts and lungs are excised.
• Left ventricle and lungs are weighed ,along with main, extra and intrapulmonary, artery are isolated.
• After 1 hr. arteries are made to contract with KCl.
• Contraction are recorded using lever transducer.
• Maximum force generated by an artery is plotted as a function of applied force and recorded on a polygraph.
• Contraction and relaxation of agonist responses of artery are assessed.
• Cumulative concentration response of KCl, Angiotensin II, and Nor - Epinephrine are plotted.
• Both the responses are plotted as a function of negative log of agonist concentration.
• To compare the differences in mean responses, t-test is applied.[5]

13. SOME OTHER MODELS
• GENETIC RAT MODELS OF
HYPERTENSION
• OBESITY RELATED HYPERTENSIVE
MODELS
• Wistar fatty rats (WFR) are derived from cross
between obese Zucker and Wistar Kyoto rats.
• These show persistence hyperinsulinemia and
hypertension after 16 week of age.
• ENVIRONMENTAL HYPERTENSION
• Stress-induced hypertension using flashing lights,
loud noise, restraint cage, and cold or hot
stimuli.[4]
Credits:- ResearchGate

14. Genetic Rat Models of
Hypertension
• A number of rat genetic models of hypertension have
been used in genetic, (patho)physiological, and
pharmacological studies. Rat strains exhibiting genetic
hypertension include the SHR, DSS rat, the fawn-hooded
hypertensive (FHH) rat, the Milan hypertensive strain,
the Lyon hypertensive rat, the Sabra hypertensive rat,
the genetically hypertensive rat, and the inherited stress-
induced arterial hypertension rat model. Of these, the
most commonly studied is the SHR. In the past 10 years,
>4500 articles were indexed in PubMed
(https://www.ncbi.nlm.nih.gov/pubmed/) under the term
spontaneously hypertensive rats.[4]
Credits:- Envigo

15. REFERENCES
• [1] https://www.who.int/news-room/fact-sheets/detail/hypertension
• [2] Dubey Harikesh, Singh Anamika, Patole Angad M, Tenpe
Chandrashekhar R , Antihypertensive effect of allicin in
dexamethasone-induced hypertensive rats, Integrative Medicine
Research, Volume 6, Issue 1,2017, Pages 60-65,ISSN 2213-4220.
• [3] Nguelefack T.B, Mekhfi H, Dongmo A.B, Dimo T, Watcho P,
Zoheir Johar, Legssyer A, Kamanyi A, Ziyyat A, Hypertensive effects
of oral administration of the aqueous extract of Solanum torvum fruits
in l-NAME treated rats: Evidence from in vivo and in vitro studies,
Journal of Ethnopharmacology, Volume 124, Issue 3,2009, Pages 592-
599, ISSN 0378-8741.
• [4] Xin-Fang Leong, Chun-Yi Ng, Kamsiah Jaarin, "Animal Models
in Cardiovascular Research: Hypertension and
Atherosclerosis", BioMed Research International, vol. 2015, Article
ID 528757, 11 pages, 2015, https://doi.org/10.1155/2015/528757
• [5] Vogel H. Gerhard, Drug Discovery and Evaluation, Springer-
Verlag Berlin Heidelberg, Second Edition, 2002, page No- 179
• [6] https://www.slideshare.net/kanthsklal/screening-of-
antihypertensive-agents

16. THANK
YOU