DEVELOPMENT OF HELICOBACTER-PYLORI-INDUCED GASTRIC-CARCINOMA IN MONGOLIAN GERBILS

Helicobacter pylori is classified by IARC/WHO as a definite human gast ric carcinogen, despite ''inadequate experimental evidence.'' To obtai n direct evidence concerning this relationship, we investigated the hi stopathological findings of gastric mucosa using a model of H. pylori infection in Mongolian gerbils, The animals were challenged p.o. with H. pylori ATCC-43504 and sacrificed at 6, 12, and 18 months after inoc ulation for histological examination. All inoculated animals were infe cted with H, pylori, Severe infiltration of the lamina propria by poly morphonuclear and mononuclear cells appeared in the lesser curvature o f the antrum, with an increase in epithelial cell proliferation, and t he infiltration extended to the body. Atrophic gastritis and focal int estinal metaplasia also appeared in the lesser curvature of the antral mucosa at 6 months after inoculation. Intestinal metaplasia became se vere, with dysplasia, after that, At 18 months after H. pylori inocula tion, two of five infected animals showed three well-differentiated ga stric cancers, The uninfected control animals showed no abnormal findi ngs throughout the entire observation period. Here, it was confirmed t hat H, pylori infection alone causes gastric cancer in an animal model .