Howden P J, Faux S P
Institute of Occupational Health, University of Birmingham, Edgbaston, UK.
Carcinogenesis. 1996 Oct;17(10):2275-7. doi: 10.1093/carcin/17.10.2275.
Treatment of isolated DNA with crocidolite and man-made vitreous fibre-21 (MMVF-21) significantly increased the concentration of 8-hydroxydeoxyguanosine (8-OHdG) in isolated DNA above background levels and co-treatment with glutathione (GSH) eliminated this effect. Crocidolite, MMVF-21 and chrysotile fibres increased the number of revertants in Salmonella typhimurium TA100 and GSH-deficient strains, TA100/NG-54 and TA100/NG-57, over background levels. This increase was small in TA100 but was greater in the GSH-deficient strains. When these bacterial strains were further depleted of GSH by co-culture with buthionine sulfoximine, all fibres tested caused a significant increase in the number of revertants over the parent strains. Pre-treatment with the GSH precursor N-acetyl-L-cysteine reduced the number of revertants to below that of the parent strain. Previous studies have shown a mechanistic role for iron-catalyzed production of oxygen radicals in the mutagenicity of fibres and this study suggests a protective role for GSH against such oxidative damage possibly by acting as a radical scavenger.
用青石棉和人造玻璃纤维-21（MMVF-21）处理分离出的DNA，可使分离出的DNA中8-羟基脱氧鸟苷（8-OHdG）的浓度显著高于本底水平，而与谷胱甘肽（GSH）共同处理可消除这种效应。青石棉、MMVF-21和温石棉纤维使鼠伤寒沙门氏菌TA100及谷胱甘肽缺陷型菌株TA100/NG-54和TA100/NG-57中的回复突变体数量高于本底水平。这种增加在TA100中较小，但在谷胱甘肽缺陷型菌株中更大。当这些细菌菌株通过与丁硫氨酸亚砜亚胺共培养进一步耗尽谷胱甘肽时，所有测试的纤维都会使回复突变体的数量比亲本菌株显著增加。用谷胱甘肽前体N-乙酰-L-半胱氨酸预处理可使回复突变体的数量降至亲本菌株以下。先前的研究表明，铁催化产生氧自由基在纤维的致突变性中起作用，而本研究表明谷胱甘肽可能通过作为自由基清除剂对这种氧化损伤起到保护作用。
