中文摘要：

目的：探讨纳米氧化铝对 ICR 小鼠神经细胞线粒体形态及功能的损伤作用。方法健康成年ICR 小鼠分别滴鼻暴露纳米氧化铝（＜50 n m）25，50和75 mg·kg -1，连续1个月。电镜观察海马 CA3区神经细胞线粒体的超微结构，并测量线粒体直径；采用定磷法测定脑皮质 Na ＋-K ＋-ATPase 与 Ca2＋-Mg2＋-ATPase 活力；Western 蛋白质印迹法检测细胞色素 c 氧化酶亚单位Ⅳ（COXⅣ），Bcl-2结合蛋白1（Beclin 1）和微管相关蛋白1轻链3Ι蛋白（LC3Ι）和 LC3Ⅱ蛋白的表达。结果与正常对照组相比，50 mg·kg -1组海马 CA3区神经元线粒体明显肿胀，内嵴结构排列稀疏，核周线粒体呈空泡化；线粒体平均直径明显增加〔（0．49±0．02）μm，P＜0．05〕；75 mg·kg -1组线粒体大多呈微球形，嵴结构排列紧密，线粒体平均直径显著降低〔（0．36±0．02）μm，P＜0．05〕。脑皮质线粒体酶活力随着染毒剂量的增加而降低，与正常对照相比，50和75 mg·kg -1组的 Na ＋-K ＋-ATPase 与 Ca2＋-Mg2＋-ATPase 活力显著降低，分别为6．37±0．22，5．48±1．53和3．21±0．99，（3．28±0．15）kU·g -1蛋白（P ＜0．05）；50和75 mg·kg -1组的 Ca2＋-Mg2＋-ATPase 活力显著降低（P＜0．05）。75 mg·kg -1组 COXⅣ蛋白表达量为1．35±0．66，显著低于其他2个剂量组（P ＜0．05）。与正常对照相比，75 mg·kg -1组 Beclin 表达量为2．23±0．20，自噬特异蛋白LC3Ⅱ/LC3Ⅰ的比例为0．45±0．10，均显著高于正常对照组（P＜0．05）。结论线粒体功能紊乱可能是纳米氧化铝神经毒性机制之一，而神经细胞可能通过自噬清除受损线粒体。

英文摘要：

OBJECTIVE To explore the potential neurotoxicity of nano-alu mina （〈50 n m）in vivo, we treated the ICR mouse with the nano-alu mina to investigate the mitochondrial da mage of nerve cells on morphology and function.METHODS Adult male mice were exposed to nano-alu mina （〈50 n m）of 0,25,50 and 75 mg·kg -1 by nasal instillation for 1 month.Then we observed the mitochondrial ultra-structure of the nerve cells in CA3 region of hippoca mpus,and measured the mean dia meter in every group.The activities of Na ＋-K ＋-ATPase and Ca2 ＋-Mg2 ＋-ATPase were tested by the determination of the inorganic phosphorus,which was the deco mposition product of ATPase.Western blot analysis was used to detect the expression of COX-Ⅳ,Beclin1 ,LC3Ιand LC3Ⅱ.RESULTS Co mpared with 0 and 25 mg·kg -1 groups exposed to Al2 O3 nanopartilces （Al2 O3 NPs）,the mitochondria of CA3 region in hip-poca mpus in 50 mg·kg -1 group beca me ede matous and swollen with sparse and broken cristae sur-rounding the nuclear,and the mean dia meter was higher（0.49 ±0.02 μm,P 〈0.05）.But co mpared with 50 mg·kg -1 group,the mitochondria in 75 mg·kg -1 group beca me s maller with inner cristae of high density,and the mean dia meter was lower（0.36 ±0.02 μm,P〈0.05）.The enzy me activity of the mito-chondria in cerebral cortex decreased dose-dependently with exposure,the activities of Na ＋-K ＋-ATPase in 50 and 75 mg·kg -1 groups（6.37 ±0.22 kU·g -1 protein,5.48 ±1 .53 kU·g -1 protein）and Ca2 ＋-Mg2 ＋-ATPase in 50 and 75 mg·kg -1 groups （3.21 ±0.99 kU·g -1 protein,3.28 ±0.15 kU·g -1 protein）were lower than the 0 mg·kg -1 group（P〈0.05）.Meanwhile,the Ca2 ＋-Mg2 ＋-ATPase in 50 and 75 mg·kg -1 groups showed lower activities in co mparison with the 25 mg·kg -1 group.The 75 mg·kg -1 group expressed higher level of the COX-Ⅳ protein 1 .35 ±0.66（P〈0.05）than other groups.Both expression of Beclin1 protein and rate of LC3Ⅱ/LC3Ⅰin 75 mg·kg -1 group were more than the 0 mg·kg -1 group.