MECHANISMS OF PROTECTION BY OMEPRAZOLE AGAINST EXPERIMENTAL GASTRIC-MUCOSAL DAMAGE IN RATS

In the present study, the protective effect of omeprazole on gastric m ucosa injury induced by ethanol . HCl in rats and the putative mechani sms involved in this action were investigated. Misoprostol and ranitid ine were used as reference drugs. The morphometric analysis of histolo gical sections showed that omeprazole caused a significant reduction o f mucosal necrotic damage, this effect being associated with a mraked increase in Alcian blue recovery from gastric bound mucus. In addition , omeprazole elicited a significant inhibition of gastric acid secreti on from pylorus-ligated rats. Misoprostol exerted similar effects to t hose obtaine with omeprazole, even if the Alcian blue recovery and the acid output were affected to a lesser extent. By contrast, ranitidine failed to influence both the mucosal damage and the Alcian blue recov ery, while it exerted a marked inhibition on acid secretion. The prese nt results indicate that omeprazole is effective in protecting gastric mucosa from necrotic damage induced by ethanol . HCl and suggest that an enhancement of gastric mucus barrier may account for this protecti ve action.