Green Tea Polyphenols Reduce Gastric Epithelial Cell Proliferation and Apoptosis Stimulated by Helicobacter pylori Infection

Recently the finding of gastric cancer in Helicobacter pylori (H. pylori)-infected mouse models was reported. Studies of humans and animal models have shown that H. pylori infection stimulates gastric epithelial cell proliferation and apoptosis. Polyphenols contained in green tea and related compounds were reported to have a variety anti-tumor effects and bactericidal properties. We studied the effect of green tea polyphenols on gastric cell proliferation and apoptosis in an H. pylori-infected mouse model. This model was prepared by inoculating Balb/c mice with 10(8) cfu of H. pylori (NCTC 11637 strain) by gavage. Beginning 18 weeks after inoculation, 0.5% polyphenols were given in drinking water every day for 2 weeks. Mice were sacrificed 1 h after bromodeoxyuridine (BrdU) was given i.p. for preparation of paraffin-embedded specimens. Cell proliferation and apoptosis were examined by the avidin-biotin complex method using anti-BrdU antibody and the TUNEL method, respectively. H. pylori infection resulted in increased BrdU-labeled cells in both the antrum and the bodies. Administration of polyphenols suppressed this increased proliferation. H. pylori infection increased apoptotic cells in both the antrum and the corpus in comparison with controls. This increase was not seen in H. pylori-infected mice given polyphenols. We conclude the administration with polyphenols might suppress gastric carcinogenesis that is in part related to H. pylori infection.