Effects of combinations of ROS scavengers on oxidative DNA damage caused by visible-light-activated camphorquinone/N,N-dimethyl-p-toluidine.
The objective of this investigation was to analyze whether various combinations of the ROS scavengers glutathione (GSH), N-acetyl-cysteine (NAC), and vitamins C and E decrease DNA damage due to visible-light-irradiated (VL-irradiated) camphorquinone/N,N-dimethyl-p-toluidine (CQ/DMT) compared with individual vitamin C or E. PhiX-174 RF plasmid DNA was used to determine single and double strand breaks as parameters of DNA damage. Individual ROS scavengers and combinations of the antioxidants were added to plasmid DNA treated with VL-irradiated CQ/DMT/Cu (II). After incubation, DNA was loaded into a 1% agarose gel. Following electrophoresis, gels stained with 0.5 microg/mL ethidium bromide were photographed under ultraviolet illumination and analyzed with NIH ImageJ software. Results were evaluated between groups for statistical significance using Student's paired t-test (p < 0.05). Glutathione significantly reduced oxidative DNA damage at all test concentrations when combined with vitamin C or vitamin E. The concentration of damaged DNA observed in the presence of combinations of GSH with vitamin C or vitamin E was significantly lower compared with all other combinations of antioxidants investigated in our study (p < 0.05). In contrast to GSH, NAC was not able to compensate the pro-oxidative effects of vitamin C and vitamin E. Only at a concentration of 2 mM, NAC combined with vitamin C efficiently prevented CQ/DMT/Cu (II)-associated DNA damage. Our data indicate that solely the combinations of GSH with vitamin C or vitamin E significantly reduce the severity of oxidative DNA damage caused by CQ/DMT, whereas NAC may even increase the pro-oxidant activity of vitamin C and vitamin E.
Lee
Seungbum
S
Department of Restorative Dentistry, School of Dentistry, University of Washington, Box 357456, Seattle, Washington 98195-7456, USA.
Pagoria
Dustin
D
Raigrodski
Ariel
A
Geurtsen
Werner
W
D000111:Acetylcysteine / Q000737:chemistry / Q000494:pharmacology; D001205:Ascorbic Acid / Q000737:chemistry / Q000494:pharmacology; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage / Q000187:drug effects*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D005978:Glutathione / Q000737:chemistry / Q000494:pharmacology*; D008027:Light; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000737:chemistry; D013729:Terpenes / Q000737:chemistry / Q000528:radiation effects; D014052:Toluidines / Q000737:chemistry / Q000528:radiation effects; D014810:Vitamin E / Q000737:chemistry / Q000494:pharmacology
D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D013729:Terpenes; D014052:Toluidines; D014810:Vitamin E; C048339:camphoroquinone; D004247:DNA; D005978:Glutathione; D001205:Ascorbic Acid; C015835:dimethyl-4-toluidine; D000111:Acetylcysteine