Cytoprotective activity in the gastric mucosa of rats exposed to carbon tetrachloride-induced liver injury.

The present study was undertaken to evaluate the cytoprotective activity in the gastric mucosa of rats subjected to CCl4-induced liver injury. Response of gastric mucosa to absolute ethanol insult or acid (pylorus ligation) after CCl4 challenge was analyzed. Intraperitoneal administration of CCl4 increased plasma AST and ALT, but liver protein and glycogen levels were decreased; in addition, gastric acid secretion was significantly increased with respect to control animals (1541 +/- 266 vs. 629 +/- 25 mu eq H+; p < 0.001). Microscopical gastric erosions were observed in 3/10 animals after CCl4 challenge. Pylorus-ligated as well as CCl4-challenged rats developed increased susceptibility to gastric lesions, compared to control (lesion indices: 4.6 +/- 0.20 vs 2.8 +/- 0.13; p < 0.05), while showing increased resistance to absolute ethanol-induced gastric damage (30.4 +/- 11.2 vs 89.7 +/- 9.7 mm, p < 0.01). PGE2 levels in the gastric mucosa were not influenced by exposure to CCl4. Ultrastructural studies revealed the presence of continuous ethanol-resistant and apparently more adherent layer of mucus in CCl4-challenged animals. Morphological evaluation revealed an increase in Alcian blue-stained mucus. A dual condition of enhanced sensitivity to HCl with increased tolerance to ethanol was observed in gastric mucosa of CCl4-treated animals. These observations could be explained by the amount and/or composition of protective mucus layer in the gastric mucosa.