毒理性
抗霉素A在消除氧气消耗的浓度下,对t-丁基过氧化氢在U937细胞中引发的毒性有轻微的抑制作用,尽管这种作用在统计学上是显著的。保护作用在处理后6小时观察到,但在24小时后不再明显。出乎意料的是,这些事件与低浓度t-丁基过氧化氢产生的DNA单链断裂的显著积累有关。实验发现,在t-丁基过氧化氢处理过程中会产生一个以氧为中心的自由基和一个以碳为中心的自由基,而抗霉素A显著降低了它们的形成。因此,抑制复合物III水平的电子传递似乎(a)减少了介导t-丁基过氧化氢致死效应的有毒物种的形成,至少部分上是这样,(b)增强了在低浓度t-丁基过氧化氢时产生的DNA损伤物种的形成。鱼藤酮和氰化物分别抑制复合物I和IV,它们并不影响t-丁基过氧化氢引发的DNA损伤。这些结果表明,DNA单链断裂并不介导t-丁基过氧化氢的毒性,特定的线粒体功能可能调节有机过氧化物产生的有毒物种和DNA损伤物种的形成。
Antimycin A at levels that abolish oxygen consumption had a slight, although statistically significant, inhibitory effect on the toxicity elicited by t-butylhydroperoxide in U937 cells. The protective effect was observed after 6 hr of post-treatment incubation, but was no longer apparent after 24 hr. Unexpectedly, these events were associated with a marked accumulation of DNA single-strand breaks produced by low levels of t-butylhydroperoxide. Both an oxygen- and a carbon-centred radical were found to arise during treatment with t-butylhydroperoxide, and their formation was significantly lowered by antimycin A. Thus inhibition of electron transport at the level of complex III appears (a) to decrease the formation of toxic species which mediate, at least partially, the lethal effects elicited by t-butylhydroperoxide, and (b) to enhance the formation of DNA-damaging species generated at low concentrations of t-butylhydroperoxide. Rotenone and cyanide, which respectively inhibit complexes I and IV, did not affect DNA damage elicited by t-butylhydroperoxide. These results suggest that DNA single-strand breaks do not mediate the toxicity of t-butylhydroperoxide, and that specific mitochondrial functions might modulate the formation of the toxic and of DNA-damaging species generated by organic hydroperoxides.
来源:Hazardous Substances Data Bank (HSDB)