Influence of Helicobacter pylori infection on healing and relapse of acetic acid ulcers in Mongolian gerbils.

Both Helicobacter pylori and NSAIDs play important roles in the healing and relapse of peptic ulcers in man. We examined how H. pylori infection, indomethacin, and their combination affects the healing of gastric ulcers and whether or not such factors provoke a relapse of healed gastric ulcers in Mongolian gerbils. Gastric ulcers were induced by serosal application of an acetic acid solution. H. pylori (ATCC43504) was orally administered once into animals with active and healed ulcers. Ulcers healed within eight weeks and remained healed for the following six months. H. pylori infection significantly delayed ulcer healing four weeks following infection. Indomethacin treatment showed a tendency to delay ulcer healing. Ulcer healing in H. pylori-infected Mongolian gerbils was significantly delayed by indomethacin. H. pylori infection resulted in a relapse of healed ulcers from one to six months after infection, with a gradual increase in size. By the fourth month following a relapse, the serum gastrin level had significantly increased. H. pylori-induced ulcers in the posterior wall coexisted with relapsed ulcers in the anterior wall five and six months later. Omeprazole markedly prevented the ulcer relapse caused by H. pylori infection. It is concluded that, in Mongolian gerbils, H. pylori infection delayed the healing of preexisting gastric ulcers and resulted in the relapse of healed ulcers, yet indomethacin had little or no effect on ulcer healing or relapse.