中文摘要：

目的探讨氟、砷及联合染毒对大鼠海马、大脑皮质神经元及神经突触超微结构影响。方法初断乳SPF级SD大鼠随机分为4组，氟、砷处理组大鼠分别自由饮用120mg／L氟化钠（NaF）和70mg／L亚砷酸钠（NaAsO2）水溶液，氟砷联合染毒组饮用120mg／LNaF＋70mg／LYaAsO2混合水溶液，对照组饮用蒸馏水；各组大鼠染毒3个月，用透射电子显微镜观察各组大鼠海马、大脑皮质神经元和突触超微结构变化。结果氟处理组和联合染毒组大鼠海马、大脑皮质组织氟含量分别为（1．14±0．35）、（1．06±0．27）、（1．19±0．42）、（1．03±0．21）μg／g，均高于对照组的（0．24±0．18）、（0．25±0．07）μg／g；砷处理组和联合染毒组大鼠海马、大脑皮质组织砷含量分别为（3．92±0．63）、（3．80±0．76）和（3．73±0．99）、（3．43±0．63）μg／g，均高于对照组的（0．16±n03）、（n14±0．02）μg/g；电镜观察可见氟、砷处理组和联合染毒组大鼠海马、大脑皮质神经元出现不同程度皱缩、核变形，胞浆内细胞器减少，线粒体肿胀、空化等；突触前膜突触小泡减少，线粒体内嵴结构不完整，突触后膜膨大水肿，线粒体空化变性等。结论氟、砷及联合染毒均可引起大鼠海马、大脑皮质神经元及突触超微结构病理改变。

英文摘要：

Objective To explore the effects of fluoride and arsenic on ultrastructure of hippocarnpus and cerebral cortical neurons and cynapses in rats. Methods The Sprague-Dawley rats at the beginning of weaning were randomly divided into four groups. The rats in fluoride and arsenic group were exposed to 120 mg/L sodium fluoride （NaF） and 70 mg/L sodium arsenite （NaAsO2 ） ,respectively, and the fluoride and arsenic co-exposure rats were exposed to 120 mg/L NaF and 70 mg/L NaAsO2 combined solution as drinking water for ninety days. The control rats drank distilled water for ninety days. Electron microscope samples were made in order to observe ultrastructural changes of neurons in hippocam- pus and cerebral cortex by transmission electron microscope（TEM）. Results The levels of fluoride in hippocampus and cerebral cortex tissues in NaF-exposed and co-exposed rats were 1.14 ±0. 35,1.06 ±0. 27 and 1.19 ±0. 42,1.03 ±0. 21 μg/g,respectively,and all much higher than those in the control（0. 24 ±0. 18 and 0. 25 ±0. 07 μg/g） and NaAsO2-ex- posed rats（0. 48 ±0. 10 and 0. 41 ±0. 03 μg/g） （all P 〈0. 01 ）. The levels of arsenic in hippocampus and cerebral cortex tissues in NaAsO2-exposed and co-exposed rats were 3.92 ±0. 63,3.80 ±0. 76 and 3.73 ±0. 99,3.43 ±0. 63 μg/g,respec- tively,and all much higher than those in the control（0. 16 ±0. 03 and 0. 14 ±0. 02 μg/g） and NaF-exposed rats（0. 16 ±0. 02 and 0. 16 ±0. 03 μg/g） （all P 〈0. 01 ）. The ultrastructure in hippocampus and cortex neurons in the NaF-exposed, NaAsO2-exposed and co-exposed rats all had pathological changes. There were obvious changes such as cell shrinkage, nuclear deformation,perinuclear mitochondrial swelling and cavitating. The pathological changes of cynapses were also observed for synaptic vesicles of presynaptic and postsynaptic membrane and the mitochondria ridge was incomplete, the synaptic cleft was expanded, and the mitochondria in postsynaptic membrane was swelled and cavitated. Conclusion Subchroni