Influence of Helicobacter pylori infection on development of stress-induced gastric mucosal injury

Immediately after the Great Hanshin Earthquake in Kobe in 1995, the recurrence rate of peptic ulcer in patients infected with Helicobacter pylori was higher than that in patients in whom H. pylori had been eradicated. We evaluated the influence of H. pylori infection on stress-induced gastric mucosal injury in Mongolian gerbils and C57BL/6 mice. These animals were immersed in water for 30, 120, and 720 min 12 weeks after inoculation with H. pylori, and then killed to assess gastric mucosal damage, and to measure cytokine production (interleukin IL]-1β, IL-4, IL-6, and IL-10; interferon IFN]-γ; and tumor necrosis factor TNF]-α) in the gastric tissue of the mice. The stress treatment for 30 min resulted in a significantly higher bleeding rate and bleeding index among infected gerbils and mice compared with results in uninfected animals. Conversely, the bleeding and ulcer indexes were significantly higher in uninfected gerbils after 720 min of the stress treatment than in infected gerbils. Prior to the stress treatment, gastric IL-1β and IFN-γ production was significantly higher in the infected group than in the uninfected group. After 120 min of the stress treatment, TNF-α production was increased in the infected group, and IL-1β and IL-10 production was increased in the uninfected group. However, the production of these cytokines showed no change at 30 min of the stress treatment. These results suggest that H. pylori infection influences the development of gastric mucosal injury in the early phase of stress exposure; cytokines do not play a major role in this process. Received: March 29, 1999 / Accepted: November 26, 1999