Modulation effect of tea polyphenol toward N-methyl-N'-nitro-N-nitrosoguanidine-induced precancerous gastric lesion in rats.

The chemopreventive effect of tea polyphenol (TP) on precancerous gastric lesion was examined. A rat model was established by gavage of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and different concentrations of TP were given to Wistar rats in drinking water during the 16 weeks of the experiment. The histopathological data showed an effect of TP to lighten the lesions induced by MNNG. By flow cytometry, we demonstrated that TP treatment decreased the proliferation and apoptosis index (AI) induced by MNNG. The arrest in the G0-G1 phase of the cell cycle was also obtained. The results suggested that TP had preventive effect against gastric carcinogenesis at the preinitiation stage and such prevention may be related to the modulation of the balance of cell death and cell proliferation.