Protective effects of antioxidants against UVA-induced DNA damage in humanskin fibroblasts in culture

Ultraviolet A radiation (UVA, 320-400 nm) is mutagenic and induces genomic damage to skin cells. N-acetyl-cysteine (NAC), selenium and zinc have been shown to have antioxidant properties and to exhibit protective effects agai nst WA cytotoxicity. The present work attempts to delineate the effect of t hese compounds on genomic integrity of human skin fibroblasts exposed to UV A radiation using the single cell gel electrophoresis (SCGE) or Comet assay . The cells were incubated with NAC (5 mM), sodium selenite (0.6 mu M) or z inc chloride (100 mu M). Then cells were embedded in low melting point agar ose, and immediately submitted to UVA fluences ranging from 1 to 6J/cm(2). In the Comet assay, the tail moment increased by 45% (1J/cm(2)) to 89% (6J/ cm(2)) in non-supplemented cells (p < 0.01). DNA damage was significantly p revented by NAG, Se and Zn, with a similar efficiency from 1 to 4J/cm(2) (p < 0.05). For the highest UVA dose (6J/cm(2)), Se and Zn were more effectiv e than NAC (p < 0.01).