Developmental changes in gastric mucus gel thickness: responsiveness to 16,16-dimethyl prostaglandin E2 and mucosal protection in the rat.

Abstract

The gastric mucosa of newborn rats is sensitive to the damaging effects of acid and ethanol. We measured gastric mucus gel thickness in newborn, suckling, and weaned rats by inversion microscopic observation. The thickness in newborn rats was 52.2 +/- 6.7 microns and increased with age, reaching 96.8 +/- 5.6 microns in 8-wk-old rats (p less than 0.001). Oral administration of 16,16-dimethyl prostaglandin E2 at concentrations of 10 and 100 micrograms/kg body weight increased mucus thickness in 8-wk-old rats but had no effect in 1-wk-old rats. We also assessed the effect of 16,16-dimethyl prostaglandin E2 on the prevention of gastric mucosal damage induced by ethanol. Oral 16,16-dimethyl prostaglandin E2 reduced damage in 8-wk-old rats, but there was no effect in 1-wk-old rats. These data suggest that the susceptibility of newborn rats to gastric mucosal injury may be related to the relative thinness of the gastric mucus gel layer and the failure of prostaglandins to increase the mucus gel layer thickness.