Enhancement of the UVA induction of haem oxygenase-1 expression by beta-carotene in human skin fibroblasts

beta-Carotene has often been discussed as a means to reduce the risk of ski n photodamage, We studied the antioxidative potential of beta-carotene in h uman skin fibroblasts exposed to ultraviolet A light. Surprisingly, we foun d a pro-oxidative effect of beta-carotene, Using the induction of haem oxyg enase-1 as a marker for oxidative stress, ne found a strong enhancement of gene expression by beta-carotene in ultraviolet A-irradiated cells, This ef fect was clearly suppressed by concomitant addition of vitamin E but only m oderately by vitamin C, The results show that beta-carotene has pro-oxidati ve properties in human skin fibroblasts exposed to ultraviolet-A light. (C) 1999 Federation of European Biochemical Societies.