锰对大鼠纹状体神经细胞凋亡的影响

目的利用锰染毒大鼠模型，分析不同浓度锰对大鼠纹状体神经细胞凋亡的影响，探讨锰神经毒性的作用机制。方法将健康雄性SD大鼠随机分成空白对照组和高、中、低3个剂量染锰组，每组6只动物。染毒结束，开颅分离取出大鼠纹状体，分别做锰含量测定、Tunel染色和透射电子显微镜观察。结果高、中、低3个剂量染锰组纹状体锰含量分别为（2．98±0．52）、（2．75±0．37）、（2．61±0．73）ng／mg，均高于空白对照组的（．60±0．20）ng／mg，差异有统计学意义（P〈0．05）。高、中、低3个剂量染锰组纹状体细胞凋亡指数分别为（24．83±5．98），（17．00±5．33），（15．33±2．58），均高于空白对照组的（2．83±0．41），差异有统计学意义（P〈0．05）。且随着染锰剂量的加大，细胞凋亡指数增加。染锰组大鼠纹状体的透射电子显微镜显示中剂量染锰时，部分纹状体神经细胞出现核变小、固缩，染色质浓集等细胞凋亡的特征性改变。结论锰可致大鼠纹状体神经细胞出现程度不同的细胞凋亡，而凋亡的程度与锰浓度有关。

Effect of manganese on apoptosis in striatum neurons of rats

OBJECTIVE: To explore the mechanism of neurotoxicity induced by manganese, and observe the effects on the apoptosis of neurons in rat striatum. METHODS: SD rats were divided into four groups, six rats each group. Three dose groups were exposed to high, middle, and low level of MnCl(2). At the end of experiment, all rats of the exposed groups and control group were decapitated, their striatums were removed and the Mn content of striatum, the apoptotic morphology, ratio and ultrastructural organization were analyzed. RESULTS: The Mn content of striatum and apoptosis index of the three dose groups exposed to high, middle, and low level of Mn were significantly higher than control group (P < 0.05). The Mn content of striatum of the three dose groups exposed to high, middle, low level of MnCl(2) and control group were 2.98 +/- 0.52, 2.75 +/- 0.37, 2.61 +/- 0.73, 0.60 +/- 0.20 respectively. The apoptosis index of striatum of the three dose groups exposed to high, middle, low level of MnCl(2) and control group were 24.83 +/- 5.98, 17.00 +/- 5.33, 15.33 +/- 2.58, 2.83 +/- 0.41 respectively, and following higher level dose, the apoptosis index increased. The nucleus of neurons in striatum become smaller, condensed, etc, and these character showed apoptosis of neurons. CONCLUSION: Mn can result in apoptotic morphology and increase level of apoptosis in striatum. The level of apoptos varies with Mn concentration.