DETECTION OF HYDROGEN-PEROXIDE AND HYDROXYL RADICALS IN MURINE SKIN FIBROBLASTS UNDER UVB IRRADIATION

The purpose of this study was to identify the active oxygen species ge nerated in murine skin fibroblasts under UVB irradiation. When fibrobl asts were exposed to UV light (UVA+UVB), hydroxyl radicals were detect able by ESR-spin trapping using DMPO as a spin trapping agent. Cell da mage induced by UVB irradiation was prevented by addition of DMSO, a t ypical hydroxyl radical scavenger. Fibroblasts treated with a catalase inhibitor 3-amino-1H-1,2,4-triazole were more sensitive to UVB irradi ation than untreated-cells, but the sensitivity was improved by additi on of DMSO. To find the origin of the hydroxyl radicals in fibroblasts during UVB irradiation, H2O2 was determined by dihydrorhodamine 123 a nd it was found that the formation of H2O2 increased under UVB irradia tion. These results suggest that UVB-irradiated skin fibroblasts produ ce H2O2 and were followed by the formation of hydroxyl radicals, proba bly derived from the Fenton-like reaction (H2O2 + Fe2+-->.OH + OH- + F e3+), which in turn damages the cells. (C) 1995 Academic Press, Inc.