[Experimental studies on gastric ulcer (6). Endoscopical evaluation of healing processes of acetic acid ulcer in rats (2): Healing, recurrence and relapse of ulcer].

The progress of acetic acid-induced gastric ulcers in rats were sequentially observed with an endoscope for 365 days, and the influences of the ulcer-induced site, age and sex on the healing, recurrence and relapse of these ulcers were investigated. Submucosal injections of 20% acetic acid at the region between the fundus and the pylorus on the anterior wall of the stomach (site A) in 7 weeks old male rats produced active round-shaped ulcers with blood coagulation and debris on the 3rd day after ulcer induction. The ulcers diminished in size with the progress of time (10--50 days), and 50% of the ulcerated rats healed with convergences of mucosal folds (35--154 days). On and after the 50th day, some diminished or healed ulcers showed signs of relapse (37% of used rats) or recurrence (40% of healed rats, 21% of used rats), with the cumulative relapse and recurrence percentage (CR%) reaching 59% on the 365th day. Ulcers in the glandular portion on the greater curvature (site B) healed significantly faster than those in site A. All of the ulcers in site B healed within 133 days and did not recur or relapse. The cumulative healing percentage (CH%) and the CR% of the ulcers in site A in 25 weeks old male rats were 33% and 67%, respectively, and those of the ulcers in site A in 7 weeks old female rats were 60% and 60%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)