Epigallocatechin-3-gallate decreases UVA-induced HPRT mutations in human skin fibroblasts accompanied by increased rates of senescence and apoptosis.

Our study was designed to determine the protective effect of epigallocatechin-3-gallate (EGCG) on cultured human skin fibroblasts (HSFs) from multiple ultraviolet A (UVA) irradiation-induced hypoxanthine-guanine phosphoribosyl transferase (HPRT) mutant colony formation and its underlying mechanisms. In our study, the mutation frequency of the HPRT gene was examined by mutagenesis assay. Cell senescence was determined by histochemical staining of senescence-associated β-galactosidase. The apoptosis rate was detected by flow cytometry. EGCG decreased the UVA-induced HPRT gene mutation frequency by 47.85%. However, EGCG further increased the number of senescent cells by 38.92% and the apoptosis rate by 56.92% in HSFs. The photo-protective effect of EGCG on multiple UVA-exposed HSFs is related to a significant reduction in UVA-induced HPRT mutant cells. This may be caused by the induction of damaged cells to proceed to senescence and apoptosis.