Healing-promoting action of teprenone, a new antiulcer agent on acetic acid ulcer in rats.

Healing promoting action of teprenone on acetic acid ulcer in rats was assessed in comparison to that of cimetidine and proglumide by histological measurements. Teprenone (100 mg/kg X 2/day, p.o.) decreased the macroscopic ulcer index and the defective area in the ulcerated region by 32.0% and 33.3%, respectively. In addition, this drug increased the decreasing index of exposed ulcer floor and the mucosal regeneration index by 28.1% and 38.0%, respectively. However, the thickness of the ulcer base and the development index of collagen fibers were little affected by this drug. Cimetidine (100 mg/kg X 2/day, p.o.) showed a 27.2% decreasing action on the macroscopic ulcer index and a 31.3% increasing action on the thickness of the ulcer base, but failed to increase the mucosal regeneration index. Specimens from the cimetidine-treated rats were characterized by marked granulation proliferation beneath the ulcer floor. The upper layer of the granulation tissue was very rich in inflammatory cells. Proglumide (250 mg/kg X 2/day, p.o.) was scarcely effective on any parameters. These results indicate that teprenone remarkably promotes the regeneration of the defective mucosa during the ulcer healing process, and the effectiveness of cimetidine according to the macroscopic observation may be due to excessive formation of granulation tissue in the defective region.