Effect of cell proliferation on healing of gastric and duodenal ulcers in rats.

The healing of acetic acid-induced gastric and duodenal ulcers was examined together with the biochemical indices of growth in gastric and duodenal mucosa in the following three groups of rats: (a) chow-fed, (b) fed an isocaloric liquid diet, (c) fed the liquid diet plus pentagastrin injections (250 micrograms/kg, 3 times/day). Animals received the diet regimen for 10 days from 1 day after induction of ulcer (day 0). Following the feeding regimens, serum gastrin levels, oxyntic gland mucosal DNA synthesis, and gastric secretory function were significantly lowered in the rats fed liquid diets. DNA synthesis in the duodenal mucosa was not different from the pre-ulcer levels. Pentagastrin significantly restored the DNA synthetic and gastric secretory activity of the liquid diet-fed rats toward the levels in the chow-fed group. In the latter group, a significant increase in DNA synthesis and levels of serum gastrin was found at day 6 (after 5 days feeding), which corresponded with a rapid, spontaneous healing of ulcers. Feeding rats liquid diet significantly delayed the healing of gastric, but not duodenal ulcers. Repeated administration of pentagastrin accelerated gastric ulcer healing in the liquid diet group toward the rate observed in the chow-fed group, but had no effect on the healing of duodenal ulcers. These results indicate that cell proliferation is an important factor in the healing of gastric ulcers.