Light microscopic quantitative investigation on the effects of prostaglandin E2 (PGE2) on the lectin binding pattern in rat gastric mucosa injured by ethanol or sodium taurocholate.

We have used quantitative lectin histochemistry to study the cellular binding of peanut agglutinin (PNA) and soybean agglutinin (SBA) at the rat gastric corpus mucosa that has been injured experimentally by either ethanol or sodium-taurocholate and was protected by pretreatment of a cytoprotective dosage of the natural prostaglandin E2 (PGE2). The investigation was carried out in order to get access to possible differences in the amounts of intracellular secretory glycoproteins, associated with the prostaglandin-administration. The stomachs of rats injured by either ethanol or taurocholate revealed significantly reduced intramucosal amounts of glycoproteins with specific affinity for PNA and SBA, whereas in the stomachs of rats equally injured by the necrotizing agents, but pretreated by prostaglandin E2, the amounts of these glycoproteins remained close to the data observed in the control animals. These results give raise to two possible explanations: a) the decrease in the amounts of intramucosal glycoproteins might be due to a shedding of epithelial cells, the extent of which would then be less high in the prostaglandin treated stomachs. b) A second concept would imply influences on the glycoprotein metabolism, suggesting opposite traffics to be induced by the necrotizing agents than by the protective ones. Taken at their face value, our findings make it very likely that i) although prostaglandin-cytoprotectian did occur, this was not associated with a complete prevention from superficial cell loss at the rat gastric corpus mucosa and ii) the cytoprotective effect of prostaglandins might be mediated by influences on the intracellular glycoprotein metabolism, a process which could favour the defensive anti-ulcerogenic factors of the gastric mucosa.