Effects of indomethacin and prednisolone on the different stages of healing of acetic acid-induced gastric ulcers in the rat.

Repeated administration of indomethacin or prednisolone for 2 weeks apparently delayed the healing of initial gastric ulcers induced by acetic acid injection in rats. While indomethacin significantly interfered with the healing of partially healed 2-week-old ulcers, prednisolone did not. Indomethacin had no effect on the healing of "unhealed" 4-week-old ulcers. However, prednisolone significantly enhanced the healing of such "unhealed" ulcers, and it decreased the weight of the connective tissue at the ulcer base and the collagen content. These results suggest that prednisolone enhances the healing of "unhealed" gastric ulcers by degrading the fibroplasia that had amply developed in the connective tissue.