Augmentation of water-immersion stress-induced gastric mucosal lesions in BALB/c mice infected with Helicobacter felis

Background and Aims: Inoculation of Helicobacter felis into the murine stomach has been reported to induce chronic gastric inflammation and may be a model of Helicobacter pylori-induced chronic gastritis. In this study, to characterize H. felis-induced gastritis, the gastric production of interleukin-1 beta (IL-1 beta) and hepatocyte growth factor (HGF) was measured in mice. Methods: Gastric mucosal lesions were induced in H. felis-infected BALB/c mice by water-immersion stress. The severity score of gastric erosions per stomach was measured as the sum of the length of erosions. Gene expression of IL-1 beta and HGF were analyzed by Northern blot analysis and production of HGF was examined using the enzyme immunoassay method. Results: Water-immersion stress induced gastric mucosal lesions accompanied by increased expression of IL-1 beta mRNA. H. felis infection evoked enhanced expression of IL-1 beta and HGF genes. When H. felis-infected mice were stressed by water immersion, the mucosal lesions were more severe than those in non-infected mice. Moreover, IL-1 beta gene expression as well as HGF production was further increased. Conclusions: Although H. felis inoculation did not cause gastric mucosal erosions by itself, it augmented the stress-induced erosions.