Identification of possible reactive oxygen species involved in ultraviolet radiation-induced oxidative DNA damage.
We have previously demonstrated that each region of the ultraviolet (UV) spectrum (UVA, UVB, and UVC) induces the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in purified calf thymus DNA and HeLa cells in a fluence-dependent manner. In the present study, we further characterize the possible reactive oxygen species (ROS) that are involved in the induction of 8-oxodGuo by UV radiation. Sodium azide, a singlet oxygen (1O2) scavenger though its quenching effect on HO. was also reported, inhibited 8-oxodGuo production in calf thymus DNA exposed to UVA, UVB, or UVC in a concentration-dependent fashion with maximal quenching effect of over 90% at a concentration of 10 mM. Catalase, at a concentration of 50 U/ml, reduced the yields of UVA- and UVB-induced 8-oxodGuo formation by approximately 50%, but had little effect on UVC-induced 8-oxodGuo production. In contrast, 50 U/ml of superoxide dismutase (SOD) did not affect induction of 8-oxodGuo by any portion of the UV spectrum. Hydroxyl radical (HO.) scavengers mannitol and dimethylsulfoxide (DMSO) moderately reduced the levels of 8-oxodGuo induced by UVA and UVB, but not those by UVC. Instead, mannitol and DMSO enhanced the formation of 8-oxodGuo induced by UVC. These results suggest that certain types of ROS are involved in UV-induced 8-oxodGuo formation with 1O2 playing the predominant role throughout the UV spectrum. Except for UVC, other ROS such as hydrogen peroxide (H2O2) and HO. may also be involved in UVA- and UVB-induced oxidative DNA damage. Superoxide anion appears not to participate in UV-induced oxidation of guanosine in calf thymus DNA, as SOD did not display any quenching effects.
Zhang
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X
Department of Dermatology, Mount Sinai School of Medicine, City University of New York, New York 10029, USA.
Rosenstein
B S
BS
Wang
Y
Y
Lebwohl
M
M
Wei
H
H
D002374:Catalase / Q000378:metabolism; D004249:DNA Damage; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D016166:Free Radical Scavengers; D008353:Mannitol / Q000494:pharmacology; D018384:Oxidative Stress; D017382:Reactive Oxygen Species; D019810:Sodium Azide / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism; D014466:Ultraviolet Rays
D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D008353:Mannitol; D019810:Sodium Azide; D002374:Catalase; D013482:Superoxide Dismutase; D004121:Dimethyl Sulfoxide