Effect of topical 16,16-dimethyl prostaglandin E2 on aspirin-induced disruption of gastric permeability barrier in dogs.

This study was designed to evaluate whether stimulation of mucus and alkaline secretion by topical 16,16-dimethyl prostaglandin E2 (dmPGE2) would protect gastric mucosa against aspirin-induced disruption of permeability barrier to lumina acid. A chambered segment of canine fundic stomach with intact vascular supply was partitioned into two compartments. One was pretreated with topical dmPGE2 (25 micrograms/15 ml isotonic acid) and the other served as control. Topical dmPGE2 resulted in 1) mucus release as evidenced by gross and microscopic examinations, 2) luminal volume gain from 0.05 +/- 0.01 to 1.05 +/- 0.30 ml/15 min (p less than 0.01) and 3) an increase in Na+ efflux from 9 +/- 4 to 165 +/- 20 muEq/15 min (p less than 0.001). These effects of dmPGE2 did not protect the gastric mucosa against disruption of permeability barrier induced by 20 mM aspirin, which resulted in a similar amount of H+ back-diffusion in dmPGE2-treated mucosa (8 +/- 7 to 129 +/- 8 muEq/15 min, p less than 0.001) and in control mucosa (from 5 +/- 7 to 118 +/- 24 muEq/15 min, p less than 0.001). Also there was no significant difference in the degree of reduction in mucosal potential difference between dmPGE2-treated mucosa (from 60 +/- 4 to 34 +/- 2 -mV p less than 0.01) and control mucosa (from 58 +/- 4 to 36 +/- 3 -mV p less than 0.001).