锰对大鼠肝脏线粒体氧化损伤的作用机制

目的:观察不同剂量的锰对大鼠肝脏线粒体的氧化损伤作用,探讨其相关机制。方法:将24只雄性SD大鼠随机均分为对照组和MnCl₂低、中、高剂量组,分别腹腔注射生理盐水和2、8、32 g/kg MnCl₂溶液,每天1次,连续30 d后取大鼠肝组织测定线粒体PT孔、线粒体膜肿胀度、线粒体膜电位、琥珀酸脱氢酶(SDH)、细胞色素C、羟自由基(OH·)和谷胱甘肽过氧化物酶(GSH-PX)。结果:各组间肝线粒体PT孔差异均有统计学意义(P<0.01);MnCl₂高剂量组线粒体膜肿胀度小于对照组和MnCl₂低剂量组(P<0.05);MnCl₂高剂量组线粒体膜电位光密度均低于其他3组(P<0.05~P<0.01)。与对照组和MnCl₂低剂量组相比,MnCl₂中、高剂量组肝线粒体SDH均下降(P<0.01),且MnCl₂中、高剂量组间差异亦有统计学意义(P<;与对照组和MnCl₂低剂量组相比,MnCl₂高剂量组肝线粒体细胞色素C上升(P<0.05)。MnCl₂高剂量组肝线粒体OH·显著高于其他3组(P<0.01);与对照组比较,MnCl₂低、中、高剂量组大鼠肝线粒体GSH-PX显著降低(P<0.05)。结论:锰可导致线粒体氧化损伤,引起大鼠肝线粒体PT孔开放、膜电位下降,SDH、GSH-PX降低,细胞色素C、OH·显著升高,对机体产生毒性作用。

The mechanism of manganese induced oxidative damage on rat liver mitochondria

Objective：To observe the oxidative damage of rat liver mitochondria induced by different doses of manganese and explore the related mechanism.Methods：Twenty four male SD rats were divided into 4 groups,6 rats in each group,including control group,low dose group,medium dose group and high dose group.The rats in control group were injected normal saline intraperitoneally and the rats in low dose,medium and high dose groups were injected 2 g·kg-1·d-1,8 g·kg-1·d-1 and 32 g·kg-1·d-1 MnCl2 intraperitoneally respectively for 30 days.The rat liver tissue was extracted and mitochondria suspension was obtained by differential centrifugation separation to measure mitochondrial PT pore,the degree of mitochondrial swelling,the mitochondrial membrane potential and the content of succinate dehydrogenase（SDH）,cytochrome C,hydroxyl radical OH· and glutathione peroxidase（GSH-PX）.Results：The mitochondrial PT pore in the four groups was different and the differences had statistical significances（P0.01）;the mitochondrial swelling degree in high dose group was lower than that in control and low dose group（P0.05）;the mitochondrial membrane potential in high dose group was decreased compared with that of other groups（P0.05-P0.01）;the content of SDH in medium and high dose group was decreased compared with that in control and low dose group（P0.01）and the difference of SDH between medium and high dose group had statistical significance（P0.01）;the cytochrome C content in high dose group was higher than that in control and low dose group（P0.05）;the content of hydroxyl radical OH· in high dose group was increased compared with that in other three groups（P0.01）;in the same time,the content of GSH-PX in low,medium and high groups decreased compared with that in control group（P0.05）.Conclusions：Manganese can induce mitochondrial oxidative damage.Manganese has the toxic effects on rat mitochondria and the toxic effects induce rat liver mitochondrial PT pore opening,decreasing the optical density of membrane potential and the content of SDH and GSH-PX,increasing the content of cytochrome C and hydroxyl radical OH· significantly.