二价锰和三价锰对神经瘤细胞线粒体膜电位的影响

采用 0 .2 5、0 .5 0、0 .75mmol/L的二价锰和三价锰分别对神经瘤细胞 (SH SY5Y)染毒 2 4h ,通过线粒体特异性染料罗丹明 1 2 3进行荧光标记 ,利用激光扫描共聚焦显微镜观察染毒细胞的膜电位变化 ,并与未染毒的细胞对照组进行比较。结果表明二价锰和三价锰均可引起线粒体膜电位的改变 (P <0 .0 5 ) ,且随剂量增高 ,有降低趋势。此外 ,在 0 .5 0mmol/L和 0 .75mmol/L剂量下 ,三价锰引起的线粒体膜电位改变比二价锰更为明显。提示线粒体膜电位的改变是锰神经细胞毒性作用的重要环节。

Effects of Manganese with Different Valences on Mitochondrial Membrane Potential in Human SH-SY5Y Cells in Vitro

Human dopaminergic SH-SY5Y cells were exposed to manganese of bivalence and trivalence at the concentrations of 0.25, 0.50, 0.75 mmol/L for 24 h respectively. The mitochondrial potential was determined by incubating the culture with Rhodamine 123, a mitochondrial specific dye, followed by laser scanning confocal microtechnique(LCSM)analyses of fluorescence signal. Results showed that Mn(Ⅱ)and Mn(Ⅲ)treatment significantly decreased fluorescence signal as compared to the controls, suggesting a diminished mitochondrial membrane potential after Mn treatment. The effects were Mn-concentration dependent. In addition, we found that Mn(Ⅲ)appeared to be more cytotoxic than Mn(Ⅱ)in altering mitochondrial membrane potential at the concentration of 0.50 mmol/L and 0.75 mmol/L. These data confirm that mitochondria may serve as the primary target for Mn cytotoxicity by altering the membrane potential.