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|標題:||UVA-induced oxidative damage to rat liver nuclei: reduction of iron ions and the relationship between lipid peroxidation and DNA damage||作者:||Shih, M.K.
|關鍵字:||UVA;DNA damage;lipid peroxidation;iron ion;cultured-mammalian-cells;human skin fibroblasts;8-hydroxydeoxyguanosine formation;membrane damage;fenton reaction;ultraviolet-a;radiation;oxygen;light;acid||Project:||Mutation Research-Genetic Toxicology and Environmental Mutagenesis||期刊/報告no：:||Mutation Research-Genetic Toxicology and Environmental Mutagenesis, Volume 438, Issue 2, Page(s) 125-132.||摘要:||
Lipid peroxidation and DNA damage and the relationship between the two events were studied in rat liver nuclei irradiated with low dose UVA. Lipid peroxidation was measured as thiobarbituric acid-reactive substances (TBARS) by spectrophotometric method and as malondialdehyde-TBA adduct by HPLC, and DNA damage was measured as 8-hydroxydeoxyguanosine (8-OH-dGu) and strand breakage (or loss of double-stranded DNA) by a fluorometric analysis of alkaline DNA unwinding method. The results show that WA irradiation by itself increased nuclear lipid peroxidation but caused little or no DNA strand breakage or 8-OH-dGu. When 0.5 mM ferric (Fe+3) or ferrous (Fe+2 ) ions were added to the nuclei during UVA irradiation, lipid peroxidation and DNA damage, measured both as 8-OH-dGu and loss of double-stranded DNA, were strongly enhanced. Lipid peroxidation occurred concurrently with the appearance of 8-OH-dCu. Fe3+ ions were reduced to Fe2+ in this UVA/Fe 2+/nuclei system. Lipid peroxidation and DNA damage were neither inhibited by scavengers of hydroxyl radical and singlet oxygen nor inhibited by superoxide dismutase and catalase. Inclusion of EDTA or chain-breaking antioxidants, butylated hydroxytoluene (BHT) and diphenylamine tan alkoxy radical scavenger), inhibited lipid peroxidation but not the level of 8-OH-dGu. BHT also did not inhibit the loss of double-stranded DNA in this system. This study demonstrates the reduction of exogenous Fe+3 by UVA when added to rat liver nuclei, and, as a result, oxidative damage is strongly enhanced. In addition, the results show that DNA damage is not a result of lipid peroxidation in this UVA/Fe2+/nuclei system. (C) 1999 Elsevier Science B.V. All rights reserved.
|Appears in Collections:||食品暨應用生物科技學系|
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