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

Immediately after the Great Hanshin Earthquake in Kobe in 1995, the recurre nce rate of peptic ulcer in patients infected with Helicobacter pylori was higher than that in patients in whom H. pylori had been eradicated. We eval uated the influence of H. pylori infection on stress-induced gastric mucosa l 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. pylor i, and then killed to assess gastric mucosal damage, and to measure cytokin e production (interleukin [IL]-1 beta, IL-4, IL-6, and IL-10; interferon [I FN]-gamma; and tumor necrosis factor [TNF]-alpha) in the gastric tissue of the mice. The stress treatment for 30 min resulted in a significantly highe r bleeding rate and bleeding index among infected gerbils and mice compared with results in uninfected animals. Conversely, the bleeding and ulcer ind exes were significantly higher in uninfected gerbils after 720 min of the s tress treatment than in infected gerbils. Prior to the stress treatment, ga stric IL-1 beta and IFN-gamma production was significantly higher in the in fected group than in the uninfected group. After 120 min of the stress trea tment, TNF-alpha production was increased in the infected group, and IL-1 b eta and IL-10 production was increased in the uninfected group. However, th e production of these cytokines showed no change at 30 min of the stress tr eatment. These results suggest that H. pylori infection influences the deve lopment of gastric mucosal injury in the early phase of stress exposure; cy tokines do not play a major role in this process.