Human Skin Fibroblast Telomeres are Shortened after Ultraviolet Irradiation

OBJECTIVE: Telomere length was used as a biomarker of cell senescence to explore the role of telomere shortening in photoageing induced by ultraviolet A (UVA) light. METHODS: Real-time polymerase chain reaction was used to determine telomere length in cultured human fibroblasts of different generations and after exposure to UVA at doses up to 10 000 mJ/cm(2). Two-way analysis of variance was used to determine whether passaging or UVA was the main factor contributing to telomere shortening. RESULTS: In nonirradiated cells, telomere length was inversely related to cell generation number. In fibroblasts exposed to UVA at a dose of 1000 or 10 000 mJ/cm(2), telomere length was significantly shorter than that of nonirradiated controls and was negatively related to UVA dose. CONCLUSIONS: Telomere length and subsequent cell viability may be affected by UVA irradiation. DNA damage caused by UVA irradiation may initiate the photoageing process and telomeres may be a useful new target for attempts to prevent photoageing.