Cytoprotection by 16,16-dimethylprostaglandin E2. Role of gastric juice and mucus gel layer.

A mechanism of cytoprotection by 16,16-dimethylprostaglandin E2 (16,16-dimethyl-PGE2) was investigated in rats with respect to possible roles of the gastric juice and the mucus gel layer. 16,16-Dimethyl-PGE2 significantly increased the volume of gastric juice and mucus thickness. In a gastric juice-emptied stomach, 16,16-dimethyl-PGE2 protected the gastric mucosa against 30% ethanol, but not against 40% ethanol. Moreover, this agent did not show any cytoprotective action even against 30% ethanol when both gastric juice and mucus gel were removed. In this situation there was no histological change in the depth of injury, whether 16,16-dimethyl-PGE2 was given as pretreatment or not. These results suggest that there are two mechanisms that may play major roles in the cytoprotection of the gastric mucosa by 16,16-dimethyl-PGE2: (a) dilution of necrotizing agents by increased gastric juice and (b) thickening of the mucus gel layer.