Hypergastrinemia increases proliferation of gastroduodenal epithelium during gastric ulcer healing in rats

We investigated if hypergastrinemia exerted any influence on the proliferation of gastroduodenal epithelium during the healing of ulcers in rats. A mucosal ulcer was induced in the corpus region of the stomach in three groups of rats, which were then given vehicle, omeprazole (400 mol/kg/day), or gastrin-17 (60 nmol/kg/day) for three or six days. A fourth group of unoperated rats served as controls. One hour before killing, ³H]thymidine was injected. The ulcer margin and corresponding control tissues were excised and processed for light microscopic determination of epithelial labeling index (LI), mitotic index, and apoptotic index. LI was also determined in other parts of the gastroduodenal mucosa. Three and six days after the ulcer operation, the LI in the vehicle-treated ulcer rats was significantly increased in the ulcer margin and in the duodenum, in comparison with the intact controls. In the ulcer margin, the mitotic index was significantly increased, in parallel with the LI; the apoptotic index remained at the control level. The LI in the ulcer margin was increased further after administration of omeprazole or gastrin-17, which elevated the plasma gastrin levels by 5–15 times. It is concluded that hypergastrinemia may increase cell proliferation in the ulcer margin, which may accelerate the rate of healing.