Effects of (-)-epigallocatechin-3-gallate on expression of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 in fibroblasts irradiated with ultraviolet A.

Abstract

BACKGROUND: It is known that ultraviolet irradiation can affect cellular function through a number of signaling pathways. (-)-epigallocatechin-3-gallate (EGCG) is the major effective component in green tea and can offer protection from ultraviolet-induced damage. In this study, we investigated the protective mechanism of EGCG on human dermal fibroblasts damaged by ultraviolet A (UVA) in vitro. METHODS: Transcription factor Jun protein levels were measured by Western blot. Matrix metalloproteinase 1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA were studied by reverse transcription-polymerase chain reaction (RT-PCR) analysis in conjunction with computer-assisted image analysis. MMP-1 and TIMP-1 proteins were quantified by enzyme-linked immunosorbent assay (ELISA). RESULTS: EGCG decreased transcription activity of Jun protein after induction by UVA. Both the mRNA and protein levels of MMP-1 were increased by UVA irradiation, while no significant changes were observed in TIMP-1 levels. The ratio of MMP-1 to TIMP-1 showed statistically significant differences compared with the control. EGCG decreased the ratio of MMP-1 to TIMP-1 by inhibiting UVA-induced MMP-1 expression (P < 0.05). CONCLUSION: EGCG can protect human fibroblasts against UVA damage by downregulating the transcription activity of Jun protein and the expression of MMP-1. The ratio of MMP-1 to TIMP-1, rather than the levels of MMP-1 or TIMP-1 alone, may play a significant role in human skin photodamage.