Relapse of acetic acid-induced gastric ulcer and gastric mucosal prostaglandin I2 level in rats.

Abstract

The healing process of acetic acid-induced gastric ulcer in rats was observed with an endoscope for 365 d after ulcer induction. The ulcers were induced by acetic acid solutions of various concentrations (2.5 (I), 5.0 (II), 10 (III) and 20% (IV); 0.05 ml). On day 3, a positive correlation was observed between the ulcer index (UI) and the concentration of acetic acid solution. On day 365, cumulative healing rates in groups I, II, III and IV amounted to 100, 100, 58.3 and 51.7%, respectively. The cumulative relapse rates in groups I, II, III and IV were 0, 13.6, 66.7 and 58.6%, respectively. Significant correlations were observed between initial UI values and cumulative healing or cumulative relapse rate. On day 365, rats were divided into two groups, a healed group and non-healed group, and the gastric mucosal prostaglandin I2 (PGI2) level was measured by bioassay. The PGI2 level around ulcers in ulcer-induced rats was higher than in normal rats, and it was higher in non-healed rats than in healed rats. Moreover, the PGI2 level was higher in those groups which showed a higher cumulative relapse rates. The above results indicated that the initial ulcer size and the PGI2 level around the ulcer might correlate to ulcer healing or exacerbation.