The expression of COX-2 and iNOS in ethanol and aspirin induced gastric ulcer rat models

Abstract

Aspirin or ethanol induced gastric ulcer rat models are the most frequently used in studies.
Aspirin and ethanol induced gastric ulcers through different pathways involving COX-2 and
iNOS. The aim of this study was to examine the expression of COX-2 and iNOS in gastric
ulcer rat model induced by ethanol and aspirin. Twenty-one Sprague Dawley rats were
divided into 7 groups i.e. control group (CA), ethanol 1st day (ED1), ethanol 3rd day (ED3),
ethanol 5th day (ED5), aspirin 4th day (AD4), aspirin 6th day (AD6), and aspirin 8th day (AD8).
Oral administration of aspirin was at 200mg/kgBW and the 100% ethanol at 1mL/200gBW.
Macroscopic and microscopic observations were done to examine the gastric mucosal
damage, COX-2 and iNOS expressions. Severe gastric ulcers were observed in ED1
and AD4 groups and mild gastric mucosal damage was observed in ED3, ED5, AD6 and
AD8 groups. Microscopically, light erosion was shown by the CA and AD8 groups. Erosion
was also shown by ED3, ED5, and AD6 groups. The most severe damage with ulcers and
heavier bleeding were shown by the ED1 and AD4 groups. Weak COX-2 expression was
found in the CA, while the highest COX-2 expression was found in the ED1. The iNOS
expression in the ethanol groups was still increasing until the 5th day (ED5). In the aspirin
groups, it reached the peak on the 3rd day (AD6), and already declined on the 5th day (AD8).
In conclusion, the damage process of ethanol induced gastric ulcer occurred faster than
that by aspirin. The highest COX-2 expression in the ethanol and aspirin groups were
shown at the onset begin. iNOS expression in ethanol induced ulcer groups still increased
until the 5th day, while in the aspirin induced ulcer groups already declined in the 5th day.