Potential protection of green tea polyphenols against ultraviolet irradiation-induced injury on rat cortical neurons

The present study was performed to investigate the possible protective effects of green tea polyphenols against ultraviolet (UV)-C light irradiation-induced cell death in the cultured rat cortical neurons. We found that UV-C light irradiation induced marked cell death tested by 3-(4,5-Dimethylthiazole-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and TdT-mediated biotin-dUTP nicked-end labeling (TUNEL) assay. Protective effects of green tea polyphenols on UV-C light irradiation-induced apoptosis in cortical neurons were demonstrated by testing the content of Bax, which is involved in cell death. The expression of active Bax in cultured rat cortical neurons was inhibited significantly by green tea polyphenols compared to UV irradiation group tested by the immunoprecipitation assay and Western blot assay. However, there were no significant changes in the contents of total Bax after treatment with green tea polyphenols in UV-C light-irradiated rat cortical neurons. Our results demonstrated that the green tea polyphenols inhibited the active Bax expression, suggesting a neuroprotective effect of green tea polyphenols against the UV-C light irradiation-induced injury on cortical neurons.