Wolf T, Bolt H M, Ottenwälder H
Institut für Arbeitsphysiologie, Universität Dortmund, F.R.G.
Toxicol Lett. 1989 Jun;47(3):295-301. doi: 10.1016/0378-4274(89)90148-3.
Single strand breaks are DNA defects caused by various chemicals. DNA strand breaks induced in vitro by chromium(VI) during the reduction of this chromium species with glutathione or hydrogen peroxide were examined. Using DNA agarose gel electrophoresis and a nick translation assay, strand breaks were detected only when chromium(VI) was reduced by hydrogen peroxide. The reduction of chromium(VI) by an excess of glutathione led to no alteration in the DNA agarose gel electrophoresis pattern of the double-stranded plasmid pBR322 DNA and in the nick translation assay, indicating that no strand breaks had occurred under these conditions. No strand breaks could be detected during the reduction by hydrogen peroxide after the addition of superoxide dismutase. This indicates that hydroxyl radicals from peroxochromium complexes may be a relevant reactive species involved in chromate genotoxicity.
单链断裂是由多种化学物质引起的DNA缺陷。研究了在谷胱甘肽或过氧化氢还原六价铬的过程中，六价铬在体外诱导的DNA链断裂。使用DNA琼脂糖凝胶电泳和缺口平移试验，仅在过氧化氢还原六价铬时检测到链断裂。过量谷胱甘肽还原六价铬导致双链质粒pBR322 DNA的DNA琼脂糖凝胶电泳图谱和缺口平移试验均无变化，表明在这些条件下未发生链断裂。添加超氧化物歧化酶后，过氧化氢还原过程中未检测到链断裂。这表明过氧铬络合物产生的羟基自由基可能是参与铬酸盐遗传毒性的相关活性物质。
