Fig. 1.

Experimental protocol for ulcer healing and ulcer recurrence according to group. Group I denotes the group of rats healed naturally up to 28 weeks after serosal injection of acetic acid, Group II denotes the group of rats treated with 8 weeks of proton pump inhibitor, intraperitoneal injections of omeprazole, and Group III denotes the group of rats receiving 8 weeks of gastroprotectant, DA-9601 in pellet diets. After 28 weeks, all rats were administered with intraperitoneal injections of 200 µg/kg recombinant IL-1β irrespective of group and sacrificed after 48 h later to observe ulcer recurrence. Meanwhile, 12 rats in each group were killed at 4 weeks after acetic acid injection and the remaining 12 rats in each group were sacrificed at 28 weeks after acetic acid injection. Preliminary study confirmed that 28 weeks of duration were enough for complete ulcer healing even without any treatment. The classification of ulcer stage was determined based on the classification of Sakita and Miwa [25] as A (active) stage, H (healing) stage, and S (scarring) stage.