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SINGLET OXYGEN INVOLVEMENT IN THE INACTIVATION OF CULTURED HUMAN FIBROBLASTS BY UVA (334 nm, 365 nm) AND NEAR‐VISIBLE (405 nm) RADIATIONS
Author(s) -
TYRRELL REX M.,
PIDOUX MIREILLE
Publication year - 1989
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1989.tb09187.x
Subject(s) - hydrogen peroxide , singlet oxygen , catalase , photochemistry , chemistry , hydroxyl radical , sodium azide , superoxide dismutase , oxidizing agent , reactive oxygen species , oxygen , scavenger , radical , biophysics , biochemistry , antioxidant , organic chemistry , biology
— The UVA (320–380 nm) radiation inactivation of mammalian cells is dependent upon the presence of oxygen. In order to examine the intermediates involved, we have irradiated cells in the presence of chemical probes which are able to modify the activity of various oxygen species. We have also examined the possibility that UVA inactivates cultured human fibroblasts via generation of intracellular hydrogen peroxide. An iron scavenger (desferrioxamine) and a hydroxyl radical scavenger (dimethylsulfoxide) protect the cells against hydrogen peroxide. Diethyldithiocarbamate (a superoxide dismutase inhibitor) and aminotriazole (a catalase inhibitor) sensitize the cells to this oxidizing agent. These data support previous reports that hydrogen peroxide inactivates as a result of the iron‐catalyzed generation of hydroxyl radical. None of these agents significantly alter the fluence‐dependent inactivation of cell populations by radiation at 365 nm. In contrast, the cells are sensitized to radiation at 334, 365 and 405 nm in the presence of deuterium (an enhancer of singlet oxygen lifetime) and are protected against radiation at 365 nm by sodium azide (a quencher of singlet oxygen). These results are consistent with the conclusion that the generation of singlet oxygen, but not hydrogen peroxide or hydroxyl radical, plays an important role in the inactivation of cultured human cells by UVA and near‐visible radiations.