Prostaglandin-induced gastric mucosal protection against stress injury. Absence of a relationship to tissue glutathione levels.

The effects of 16,16 dimethyl prostaglandin E2 (dmPGE2) on the gastric mucosa of rats subjected to 1, 2, and 24 hours of water immersion stress were examined histologically. Results indicated a time-related increase in the total percentage length of glandular mucosa injured in normal saline (NS) pretreated rats that was significantly attenuated by subcutaneous dmPGE2 pretreatment (5 micrograms/kg) after 1 hour (46.0 +/- 12.9 vs. 16.8 +/- 2.3; p less than 0.005), 2 hours (45.4 +/- 1.0 vs. 13.8 +/- 2.2; p less than 0.001), and 24 hours (93.1 +/- 2.6 vs. 65.1 +/- 7.0; p less than 0.005) of water immersion stress. Moreover, dmPGE2 essentially prevented the occurrence of deep, glandular injury that, in NS controls, involved approximately 13% and 26% of the mucosal surface after 2 and 24 hours of immersion stress, respectively. Additionally, tissue levels of glutathione (mumole/g weight of wet tissue) were measured to determine its role under such conditions. After 1 hour of stress, there were no differences in glutathione levels between NS or dmPGE2 pretreated animals and fasted controls. After 2 and 24 hours of stress, there were likewise no differences in glutathione levels between NS and dmPGE2 pretreated groups, although levels in both groups were significantly decreased from fasted controls by approximately 30% at 2 hours and 37-47% after 24 hours. These histologic and biochemical data indicate that dmPGE2 attenuates both the extent and depth of glandular mucosal injury and does so in a manner unrelated to alterations in glutathione levels in gastric epithelium.