title: The effect of antioxidants on oxidative DNA damage induced by visible-light-irradiated camphorquinone/N,N-dimethyl-p-toluidine.
abstract: Previous investigations have found that visible-light (VL)-irradiated camphorquinone (CQ), in the presence of a tertiary amine (e.g., N,N-dimethyl-p-toluidine, DMT), generates reactive oxygen species and causes oxidative DNA damage in vitro. In this study, oxidative DNA damage produced by VL-irradiated CQ/DMT, in the presence and absence of antioxidants (glutathione, N-acetyl-L-cysteine (NAC), mannitol, vitamin C, and vitamin E), was measured by the conversion of PhiX-174 RF I supercoiled (SC) double-stranded plasmid DNA into open and linear forms. VL-irradiated CQ/DMT, lacking antioxidant, damaged 99.4 +/- 1% of the PhiX-174 RF I SC double-stranded plasmid DNA. Our results revealed that glutathione (10.0, 5.0, 2.5, 1.0, and 0.5 mm) and NAC (10.0, 5.0, and 2.5 mm) significantly (p < 0.02) reduced oxidative DNA damage produced by VL-irradiated CQ/DMT. Vitamin E, vitamin C, and mannitol were ineffective at reducing oxidative DNA damage produced by VL-irradiated CQ/DMT. Furthermore, vitamin E (10.0 and 5.0 mm) and vitamin C (10.0, 5.0, 2.5, 1.0, 0.5 mm) treatment significantly (p < 0.02) enhanced VL-irradiated CQ/DMT-induced oxidative DNA damage and caused significant (p < 0.001) DNA damage following VL-irradiation in the absence of CQ/DMT. As a result, future studies should evaluate whether glutathione and NAC effectively reduce or prevent oxidative damage induced by VL-irradiated CQ/DMT in vivo.
authors.affiliation: Department of Restorative Dentistry/Division of Operative Dentistry, School of Dentistry, University of Washington, Seattle, 98195-7456, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Winter
authors.forename: Dustin
authors.initials: D
authors.lastname: Pagoria
authors.forename: Werner
authors.initials: W
authors.lastname: Geurtsen
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D001826:Body Fluids / Q000737:chemistry; D001843:Bone Cements / Q000737:chemistry / Q000528:radiation effects; D004247:DNA / Q000032:analysis / Q000737:chemistry*; D004249:DNA Damage; D006801:Humans; D008027:Light; D008422:Materials Testing; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000737:chemistry; D013729:Terpenes / Q000737:chemistry* / Q000528:radiation effects*; D014052:Toluidines / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D000975:Antioxidants; D001843:Bone Cements; D017382:Reactive Oxygen Species; D013729:Terpenes; D014052:Toluidines; C048339:camphoroquinone; D004247:DNA; C015835:dimethyl-4-toluidine