Ghio A J, Kennedy T P, Stonehuerner J G, Crumbliss A L, Hoidal J R
Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710.
Arch Biochem Biophys. 1994 May 15;311(1):13-8. doi: 10.1006/abbi.1994.1202.
Surface functional groups on silicate dusts complex iron cations which can cycle through reduction and oxidation states to generate free radicals. These oxidants have a capacity to produce DNA strand breaks and mutations which are primary events in cancer induction. A differential in the capacity of fibrous silicates to produce carcinoma is recognized with the amphiboles demonstrating a greater biologic effect than the serpentine fiber chrysotile. We tested the hypothesis that the differences in genotoxicity of these fibrous silicates correspond to varying concentrations of iron complexed to the surface. Relative to chrysotile, the amphibole fibers complexed greater amounts of iron cations from both inorganic and in vivo sources. Increased concentrations of surface-complexed iron were associated with greater oxidant generation, measured as thiobarbituric acid-reactive products of deoxyribose, and more covalently closed, circular DNA strand scission. These results indicate that genotoxic effects of these fibers may correspond to their capacity to complex iron at the surface.
硅酸盐粉尘上的表面官能团能络合铁阳离子，这些铁阳离子可在还原态和氧化态之间循环以产生自由基。这些氧化剂有能力导致DNA链断裂和突变，而这是诱发癌症的主要事件。人们认识到纤维状硅酸盐诱发癌症的能力存在差异，其中闪石类显示出比蛇纹石纤维温石棉更大的生物学效应。我们检验了这样一个假说：这些纤维状硅酸盐的遗传毒性差异与表面络合铁的不同浓度相对应。相对于温石棉，闪石类纤维从无机和体内来源络合了更多量的铁阳离子。表面络合铁浓度的增加与更多的氧化剂生成相关，氧化剂生成量通过脱氧核糖的硫代巴比妥酸反应产物来衡量，同时也与更多的共价闭合环状DNA链断裂相关。这些结果表明，这些纤维的遗传毒性效应可能与其在表面络合铁的能力相对应。
