锰致大鼠脑线粒体氧化损伤及NAC干预的实验研究

Experimental Study on Mn-induced Oxidative Damage and Preventive Effect of NAC

目的通过线粒体孵育液染锰并用NAC干预研究锰致大鼠脑线粒体氧化损伤的影响。方法Wistar大鼠12只，麻醉后断头取脑，梯度离心得线粒体液。将所得线粒体液分为6组，第1组为对照组；第2～5组为不同剂量染锰组，分别加入5、50、500、1000umol／L MnCl2；第6组为NAC预处理组，线粒体液先用500umol／L NAC预处理1h后加500umol／L MnCl2。各组于培养箱内30℃孵育2h后测MDA和GSH含量及线粒体膜电位，每个指标重复测量6次。结果与对照组相比，50、500、1000mmol／l。染锰组MDA含量显著升高；500、1000umol／L染锰组GSH含量显著降低；50、500、1000mmol／L染锰组线粒体膜电位显著降低（P〈0．05）。且在一定范围内随着MnCl2剂量增加，MDA含量有升高趋势，GSH含量和线粒体膜电位有降低趋势。与单纯染锰组相比，NAC预处理组MDA含量显著降低，GSH含量和线粒体膜电位显著升高（P〈0．05）。结论锰可以剂量依赖性地诱导大鼠脑线粒体氧化损伤；NAC预处理能有效预防锰所致大鼠脑线粒体氧化损伤。

Objective To elucidate the effect of MnCl2 exposure on oxidative damage of mitochondria isolated from rat brain and the preventive effect of NAC in vitro. Methods Mitochondria were prepared from Wistar rats＇ whole brain using differential centrifugation. In vitro, mitochondria were incubated in the assay buffer containing different concentrations of MnCl2 （5, 50, 500 and 1000 umol/L） at 30℃ for 2 h. The effect of NAC （500 umol/L） was studied at a MnCl2 concentration of 500 umol/L. The level of MDA, GSH and mitochondrion membrane potential was investigated. Results As compared with the control group, the level of MDA in 50, 500 and 1000 umol/L MnCl2 groups were significantly increased; the levels of GSH in 500, 1000 umol/L MnCl2 groups were significantly decreased. mitochondrion membrane potential in 50, 500 and 1000 umol/L MnCl2 groups were significantly decreased （P〈0.05）. As compared with the 500 umol/L MnCl2 group, the level of MDA in 500 umol/L NAC pretreated group was significantly decreased, the levels of GSH and mitochondrion membrane potential in 500 umol/L NAC pretreated group were significantly increased （P〈0.05）. Conclusions Manganese could dose-dependently induce the oxidative damage of mitochondria isolated from rat brain. And this change could be prevented by pre-treatment with NAC.