Detection of dichromate (VI)-induced DNA strand breaks and formation of paramagnetic chromium in multiple mouse organs
Detection of dichromate (VI)-induced DNA strand breaks and formation of paramagnetic chromium in multiple mouse organs
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DOI：
10.1006/taap.2000.9081
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发表时间：
2001-01-01
影响因子：
3.8
通讯作者：
Sugiyama, M
中科院分区：
文献类型：
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作者：
Ueno, S;Kashimoto, T;Sugiyama, M
DNA单链断裂用碱性单细胞凝胶电泳（SCC）（Comet）分析了Cr（VI）诱导的5个器官中的碱性位点（和/或碱不稳定位点）（肝，肾，脾，肺和脑）的雄性小鼠给予钾（2）铬（2）O（7）（20 mg Cr/kg），并通过电子自旋共振（ESR）谱研究了这些器官中顺磁性Cr（V）的形成。此外，在体内的去铁胺（DFO），铁螯合剂，和二甲基硫脲（DMTU），羟基自由基清除剂，对铬（V）的形成和DNA链断裂的金属诱导的肝脏和肾脏的影响进行了检查。SCG法检测到DNA链断裂检测在肝脏和肾脏中在15分钟，并显示它们在Cr（VI）注射后3小时被修复。在注射Cr（VI）后的15 min ~ 24 h，在肝脏和肾脏中也观察到顺磁性Cr（V）的ESR谱。相反，在脾、肺或脑中没有显著水平的DNA链断裂和Cr（V）。DFO预处理可减少Cr（VI）诱导的DNA链断裂和Cr（V）复合物的形成，并可降低注射后15 min肝、肾中Cr的总含量。在DMTU预处理的情况下，在15分钟时，Cr（VI）诱导的肝和肾中DNA链断裂被抑制，而对器官中Cr（V）络合物水平和总Cr含量没有任何影响。体外实验结果表明，DFO可降低Cr（V）-GSH复合物和Cr（V）介导的羟自由基水平，而DMTU仅降低Cr（V）介导的羟自由基水平，而不影响Cr（V）-GSH复合物的形成。这些结果表明，SCG试验可能是有用的检测DNA链断裂和/或碱不稳定的网站所造成的Cr（VI）在体内。结果还表明，Cr（VI）还原过程中体内羟基自由基的形成可能在Cr（VI）引起的DNA链断裂的诱导中起重要作用，并暗示细胞内Cr（V）的水平可能并不总是与DNA链断裂的诱导有关。(C)北京：科学出版社.
DNA single-strand breaks (and/or alkali-labile sites) induced by Cr(VI) were evaluated with the alkaline single cell gel electrophoresis (SCC) (Comet) assay in five organs (liver, kidney, spleen, lung, and brain) of male mice dosed with K(2)Cr(2)O(7) (20 mg Cr/kg) by a single ip injection in vivo, and the formation of paramagnetic Cr(V) in these organs was investigated by electron spin resonance (ESR) spectrometry. Furthermore, the in vivo effects of deferoxamine (DFO), an iron chelator, and dimethylthiourea (DMTU), a hydroxyl radical scavenger, on the formation of Cr(V) and DNA strand breaks induced by the metal in the liver and kidney were examined. SCG assay detected DNA strand breaks were detected in the liver and kidney at 15 min and showed that they were being repaired at 3 h after Cr(VI) injection. The ESR spectra of paramagnetic Cr(V) were also observed in the liver and kidney for 15 min to 24 h after Cr(VI) injection. In contrast, there were no significant levels of DNA strand breaks and Cr(V) in the spleen, lung, or brain. The pretreatment of mice with DFO reduced the formation of Cr(VI)-induced DNA strand breaks and Cr(V) complexes as well as the total contents of Cr in the liver and kidney at 15 min after the metal injection. In the case of the pretreatment with DMTU, DNA strand breaks induced by Cr(VI) were suppressed in the liver and kidney at 15 min, without any influence on the levels of Cr(V) complexes and total Cr contents in the organs. The in vitro study showed that DFO decreased the levels of Cr(V)-GSH complexes and Cr(V)-mediated hydroxyl radicals, while DMTU reduced only the levels of Cr(V)-mediated hydroxyl radicals without affecting the formation of Cr(V)-GSH complexes. These results demonstrated that the SCG assay may be useful for detecting DNA strand breaks and/or alkali-labile sites caused by Cr(VI) in vivo. The results also indicated that the in vivo formation of hydroxyl radicals during the reduction of Cr(VI) may play an important role in the induction of the DNA strand breaks caused by this metal and implied that the levels of Cr(V) inside the cells may not always be related to the induction of DNA strand breaks. (C) 2001 Academic Press.