Preclinical model for antiulcer study.

1. PYLORUS LIGATION METHOD
INDUCED GASTRIC ULCER
Prepared by
Rangnath R. Chikane
M.Pharmcy Pharmacology
First Year (Sem -1st)

2. Content :-
1. Introduction
2. Regulation of Gastric Secretion
3. Requirements of an ideal model
4. Ideal model for screening anti ulcer agent
5. Animal model for screening
6. Pylorus ligation induced ulcer in rats
Principal
Requirements
Procedure
Inference
8. References

3. INTRODUCTION
 Peptic ulcer is one of the most prevalent chronic gastrointestinal
disorder.
 Cause due to imbalance between
Acid , Pepsin, Bile And Prostaglandins, Mucus, Bicarbonate,
Blood flow
 Reason for imbalance are-
Faulty dietary habits, smoking, alcohol, drug, hereditary factors,
H.Pylori etc.

5. Requirements of an ideal model
• Should be simple, reprodicible and allow for easy
quantification of reasult.
• Should induced characteristic ulceration in specific
location.
• Should involved different mechanism by which ulceration is
produced
• Ulcer produced should not spontaneously heal during
obseravation

6. Ideal animal for screening anti ulcer agent….?
RATS
Because……
•Continuous secretions of acid
•Glandular portion of rat stomach analogous to body of
stomach in man both anatomically and functionaly.
•Being omnivorous resembles man nutrition.

7. ANIMAL MODEL FOR SCREENING
1. Pylorus ligation induced gastric ulcer in rats.
2. Drug (NSAID) induced gastric ulcer in rats.
3. Ethanol induced gastric ulcer in rats.
4. Acetic acid induced gastric ulcer in rats.
5. Stress induced gastric ulcer in rats.
6. Histamine induced gastric ulcer in rats.

8. Pylorus ligation induced gastric ulcer in rats
Principal :-
• Pylorus ligation in rats leads to accumulation of gastric
acid in the stomach leading to acute gastric ulceration.
•Pylorus ligation stimulates the gastric acid output by a
long vago-vagal reflex in innervated animals and by an
intramural reflex in chronically vagotomized animals.
• First demonstrated by Shay and co worker in 1945.

9. Requirements:-
• Albino Wistar Rats (150-200 g)
•Drugs : Ether (Anesthesia)
Saline (control)
Omeprazole (Standard)
Test Drug (3 different concentration x, 2x, 4x
• Reagent : (NAOH 0.1N )
Tofers reagent (dimethyl amino azo
benzene)
Phenolphathalein
• Dissect microscope, pH meter, Burette, Surgical
instrument.

10. Procedure:-
Rats fasted for 24 hours prior to pyloric ligastion.
Randomaly divided into 5 groups of 3 of each.
Group 1- controlled vehicle
Group 2- standard drug ( Omeprazole)
Group 3- X concentration of test drug
. Group 4- 2x concentration of test drug
. Group 5- 4x concentration of test drug
Drug administerdr once for 2 days and 30 minutes prior to ligastion.

11. • Rats anesthetized with ether.
• Pyloric ligation procedure done .
• Rats place on separate cage and allow to recover.
• 19 hours after pyloric lingation, animal sacrified by
decapitation.
• Abdomen open and stomach dissected out.
• Contents of the stomach collected in centrifuge tube.

12. Stomach opened along greater curveture and ulcer observed
under 10x magnification.
EVALUATION An ulcer index UI is calculated:
UI = UN+US+UP×10–1
• UN=average of number of ulcers per animal
• US=average of severity score
• UP=percentage of animals with ulcers
Intensity of ulcer is scored as below
. 0- Normal stomach
. 1- Superficial mucosal erosion
. 2- Deep ulcer
. 3- penetrated or perforated ulcer.

13. • Content of stomach analyzed for
• Volume
• pH
• Free acidity and total acidity-
• Titration of the solution against 0.01 N NaOH using Tofers
reagent and phenolphalein as a indicator .
• Volume of NaOH turn the solution yellowish orange
corresponded to the free acidity . Titration is continued till
solution turns pink.
• The total volume of NaOH use up corresponds to total
acidity.
• Acidity ( Meg/l/100g) = Volume of NaOH * Normality * 100 /
0.1

14. Group Volume (
ml)
pH Free
acidity
Total
acidity
Ulcer
index
1
2
3
4
5

15. Inference:-
• Ulcer index of test drug compared with control group to
detect anti-ulcer effect of test drug.
• If present , it is copmare with that of standard group.
• Other parameters help to infer the mechanism of ulcer
protection.
• Eg.
• Decrease in Volume, free and total acidity – anti secretary
action
• . Rise in pH- Acid neutralizing action
• Increase in mucin , PG- Cytoprotective effect

16. References:-
1. Drug Discovery and evaluation Pharmacological assy by H.
Gerhard Vogel , second edition.
2. Research artical Determination of ant ulcer property of
sodium chromoglycate in pylorusligation ligated albino
rats, by Vivek Shrivastav, A.H. M. Viswanathaswamy,
Govind Mohan.
3. Essential of Medica Pharmacology by KD Tripathi sixth
edition.

17. THANK YOU FOR YOUR
ATTENTION