Studies On The Relationship Between Helicobacter Pylori Infection And Gastric Carcinogenesis In Animal Model

BACKGROUND In 1998 Japanese researchers, Watanabe et al, demonstrated successfully that long-term infection with H. pylon could induce gastric adenocarcinoma in Mongolian gerbils. Their result was an important discovery for studying and demonstrating directly the relationship between H. pylon infection and gastric carcinogenesis. However the mechanisms that long-term infection with H. pylon can induce adenocarcinoma in Mongolian gerbils have not been elucidated. AIMS (1) To investigate pathologic changes in stomach during H. pylon long- term infection by development of Mongolian gerbil model of H. pyloni.long- term infection. (2) To explore whether H. pylon infection can induce gastric adenocarcinoma on the basis of development of Mongolian gerbil model of long-term infection with H. pylon. METHODS (1) Development of Mongolian gerbil model of long-term infection with H. pylon NCTC 11637. (2) Experimental studies on the mechanisms that H. pylon infection can induce gastric cancer: @ BrdU and PCNA in -6- Mongolian gerbil model of long-term infection with H. pylon were examined with the immunohistochemical straining. ?Gastric cell apoptosis in Mongolian gerbil model with H. pylon long-term infection was examined with the TUNEL method. ?The expression of EGF mRNA, EGFR mRNA, FAS mRNA and FASL mRNA in Mongolian gerbil model with H. pylon long-term infection were examined with the hybridization in situ. ~ The expression of cyclin E mRNA and c-fos mRNA in Mongolian gerbil model with H. pylon long-term infection were examined with RT-PCR. ?The expression of cyclin E and c-fos in Mongolian gerbil model with H. pylon long-term infection were examined with the immunohistochemical straining. RESULTS (1) Mongolian gerbil model with H. pylon long-term infection was developed successfully. It was showed H. pylon could induce the process progressing from normal gastric mucosa through chronic gastnitis, glandular atrophy, intestinal metaplasis to atypical hyperplasia; though early adenocarcinoma was not found in all experimental animals. (2) Experimental studies on the mechanisms that H. pylon infection can induce gastric cancer: ?Immunohistochemical straining of BrdU and PCNA showed H. pylon infection induced increasion of gastric cell proliferation (P