Collagen and collagenase in ulcer tissue--2. Restraint and water immersion induced gastric lesions and effects of cimetidine and misoprostol.

Collagenase activity was considered to play an important role in the process of ulcer formation, as one of the aggressive factors. We measured the collagen metabolism using the restraint and water immersion stress ulcer model with time and studied the effects of cimetidine and misoprostol (PGE1 derivative) on the collagen metabolism. The active forms and total collagenases in the gastric mucosal connective tissues were elevated as early as at two hours after loading by restraint and water immersion stress, and a decrease in the amount of collagen (as hydroxyproline) was observed. Increase in the collagenase activity was inhibited in groups to which cimetidine or misoprostol was given before restraint and water immersion. From these results it is believed that an elevation of collagenase activity related directly to tissue destruction might be involved, as well as a decrease in the gastric mucosal blood flow, in the etiology of ulcers due to restraint and water immersion stress.