This document describes an experiment to study the anti-ulcer activity of drugs like ranitidine and cimetidine using a pylorus ligation rat model. Rats were divided into control, cimetidine, and ranitidine groups. The pylorus of rats were ligated for 4 hours to induce ulcers. Drugs were administered before ligation. After ligation, gastric contents were analyzed for volume, pH, and acidity. Stomachs were examined for ulcers. Cimetidine and ranitidine showed reduced gastric acid secretion and fewer ulcers compared to controls, demonstrating their antiulcer activity.

1. Mr. Vishal Balakrushna Jadhav
Assistant Professor (Pharmacology)
GES’s Sir Dr. M. S. Gosavi COPER, Nashik-5
ExperimentNo. 4
Study of anti-ulcer activity of a drug
using pylorus ligand (SHAY) rat model
1

2. • Objective
• Principle
• Requirements
• Procedure
• Observation table
• Result and Interpretation
Overview of Discussion
2

3. To study antisecretory and ulcer protective effect of
ranitidine/cimetidine inpylorus ligated rats.
Objective
3

4. Peptic ulcer constitute a major disease that affect human
gastrointestinal tract. The common clinical features of peptic
ulcers are hyperacid secretion and ulcer formation in the stomach
(gastric ulcers) and duodenum (duodenal ulcers) of intestine.
Acute gastric ulcers can be produced in the laboratory animals by the
use of corrosives substances such as alcohol, aspirin or
indomathacin, or by surgical manipulation like pylorus ligation, or
by subjecting the animals to acute stressful conditions. The most
commonly used technique is pylorus ligation- induced acid
secretion and ulcer formation. The procedure is simple and
produces reliable number of gastric ulcers.
Drugs like H2 blockers (e.g. ranitidine, cimetidine etc.) and proton
pump inhibitors (e.g. omeprazole etc.) inhibit pyloric ligation-
induced peptic ulcers.
The pylorus ligation was first demonstrated by Shay (1945). Ligation
of rat pylorus results gastric acid accumulation in the fore-
stomach leads to acute gastric ulcers.
Principle
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5. Animals Albino Wistar rats (150-200 g, overnight fasted).
Drugs Anaesthetic Ether, Cimetidine (10 mg/ kg, i.p. Prepare a
stock solution containing 2 mg/ml of the drug and inject 0.5 ml/
100 g body weight of the animal) or Ranitidine (20 mg/kg, p.o.)
Reagents 0.1 N NaOH, Phenolphthalein, Topfer’s reagent, 0.9%
normal saline, collodion.
Instruments Dissecting microscope (10X magnification), burette,
pH meter, surgical instruments.
Requirements
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6.  Anaesthetize the overnight fasted rats with anaesthetic ether.
 Secure the rat on the operation table. Give an incision of 1 cm long in
the abdomen just below the sternum. Expose the stomach. Pass a
thread around the pyloric sphincter and apply a tight knot. While
putting the knot care should be taken so that no blood vessel is tied
along the knot. Close the abdomen wall by putting the sutures,
Clean the skin from any blood spots and bleeding. Apply collodion
over the wound. Keep the rat in a separate cage and allow it to
recover.
 To another rat inject Cimetidine (10 mg/ kg, i.p.) or Ranitidine (20
mg/kg, p.o.). After 15 minutes perform the pylorus ligation as
described in step 2.
 After 4 hours of pylorus ligation sacrifice both the animals by
decapitation. Open the abdomen and tie the esophageal end
(cardiac end) of the stomach. Cut and remove the entire stomach
from the body of the animal.
Procedure
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7.  Give a small cut to the pyloric region just above the knot and collect
the contents of the stomach in a graduated centrifuge tube.
 Open the stomach along the greater curvature and wash it slowly
under the running tap water. Put it on the glass slide and observe
under 10X magnification for ulcers. Score the ulcers as below-
Intensity of ulcers with scoring-
 0 – normal coloration;
 0.5 – red coloration;
 1 – spot ulcer;
 1.5 – hemorrhagic streaks (bands)
 2 – deep ulcer (ulcer count ≥ 3 but ≤ 5)
 3 – perforations (ulcer count > 5)
 Mean ulcer score for each animal is expressed as ulcer index.
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8.  Analysis of stomach contents- Centrifuge the gastric content at 1000
rpm for 10 minutes. Note the volume. Pipette out 1 ml of supernatent
liquid and dilute it to 10 ml with distilled water. Note the pH of this
solution with the help of pH meter. Titrate the solution against 0.01 N
NaOH using Topfer’s reagent as indicator. (Topfer’s reagent is
dimethylaminoazobenzene with phenolphthalein and used for
detection and estimation of HCl and total acidity in gastric fluids).
Titrate to the end point when the solution turns to orange colour. The
volume of NaOH used is to be noted to estimate free acidity. Titration
has to be continued till the appearance of pink colour and the volume
of NaOH run down is to be noted to calculate total acidity. Acidity
(mEq/l/100 g) can be expressed as-
 Compare the gastric volume, acidity and ulcer index of control animals
and the animals treated with cimetidine.
 Report the readings in observation table. Interpret and conclude the
result. 8

9. Sr.No. Treatment
Dose
(mg/kg,
i.p./ p.o.)
Volume of
gastric
content
(ml)
pH
Acidity (mEq/l
/100 g) Ulcer
Index
Free Total
1
Control*
2
3
Cimetidine*
4
5
Ranitidine*
6
Observation table
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* Pylorus ligation for 4 hours

10.  Comparison of ulcer index between study groups estimates
the potency of antiulcer activity of test drug. Decrease in
volume of gastric contents, free and total acidity
determines antisecretory activity of test drug and rise in pH
evaluates acid neutralizing action of the drug.
 Cimetidine/ Ranitidine reduces gastric acid secretion and
inhibits ulcer formation in pyloric ligated animals.
Result and Interpretation
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