锰对神经细胞超微结构的影响

Effect of manganese on the ultrastructure of neurone

目的为探讨锰(Mn)神经毒性的作用机制,利用原代培养的神经细胞模型,探讨不同浓度Mn对神经细胞超微结构的影响。方法新生Wistar大鼠大脑皮层神经细胞原代培养,不同浓度Mn染毒,以MTT试验结果作细胞存活曲线。选取3个MTT试验结果差异有显著性差异的点值设定染Mn的低、中、高剂量组,透射电镜观察各组超微结构改变。结果01mmolL染Mn24h神经细胞存活率与对照组比较,差异无显著性,04～8mmolL染Mn后24h神经细胞存活率明显下降且存在剂量反应关系。以01、04、1mmolL为染Mn低、中、高剂量组,透射电镜显示各剂量组超微结构改变特征不同。低剂量组见粗面内质网增生,中剂量组以胞核改变最为明显,高剂量组以溶酶体改变为主。结论Mn在体外可剂量依赖性地引起神经细胞死亡,不同浓度Mn作用引起细胞超微结构改变的特征不同。

Objective To explore the mechanism of neurotoxicity induced by manganese(Mn),the effects on the ultrastructure of neurone have been observed.Methods Neurone primary cultures were prepared from cerebral cortex of neonatal Wistar rats.Cells were treated with 0～8 mmol/L Mn and MTT assay was used to analysis neuronal viability.According to the results of MTT assay,three dose groups exposed to high,middle,and low level of Mn were set and ultrastructre changes were observed in each group by transmission electron microscope.Results Cell viability showed no decrease in the presence of 0.1 mmol/L Mn. Mn decreased cell viability at the concentration of 0.4～8 mmol/L.Different features of ultrastructure change were observed in cells exposed to different concentration of Mn.Endoplasmic reticulum hyperplasia was mainly observed in cells treated with low dose of Mn(0.1 mmol/L),yet lysosomes changes mainly occurred in the group of high dose (1 mmol/L).The feature of apoptosis was shown chiefly in the group of middle dose of Mn (0.4 mmol/L).Conclusion Mn induced neurone death in a concentration-dependent fashion.Characters of ultrastructure change varied with Mn cocnentration.