Ethanol-induced damage to mucosal capillaries of rat stomach. Ultrastructural features and effects of prostaglandin F2 beta and cysteamine.

Impairment of the mucosal microcirculation may contribute to ethanol-induced gastric mucosal damage. In this report, we describe diffuse and severe ultrastructural damage to the capillaries of the gastric glandular mucosa of the rat that occurred within 1 min after intragastric instillation of 100% ethanol. There was a gradient of damage in that endothelial cell structure was most severely disrupted in profiles of capillaries located close to the luminal surface but some morphologic evidence of damage was evident in the wall of capillary profiles to a mean depth of 256 micron. Capillary structure was generally normal in the deeper regions of the mucosa. Pretreatment with intragastric cysteamine, 30 mg/100 g, or intragastric prostaglandin F2 beta, 0.5 mg/100 g, significantly reduced the depth in the mucosa to which damage to capillaries extended. Pretreatment with intragastric prostaglandin F2 beta, 0.2 mg/100 g, afforded no significant protection. We conclude that a 1-min exposure to 100% ethanol induces striking damage to the microcirculation of glandular mucosa of the rat stomach with severe damage to capillary profiles near the lumen and sparing of capillary profiles near the muscularis mucosa, and pretreatment with the sulfhydryl agent, cysteamine, or with a large dose of prostaglandin F2 beta reduces the extent of but does not abolish ethanol-induced damage to gastric mucosal capillaries.