title: Changes in the synaptic structure of hippocampal neurons and impairment of spatial memory in a rat model caused by chronic arsenite exposure.
abstract: Many epidemiological studies and in vitro experiments have found that chronic arsenic exposure may influence memory formation. The goal of this study was to create an animal model of memory impairment induced by chronic arsenite exposure and to study the underlying mechanisms. Sixty male Sprague-Dawley (SD) male rats were randomly divided into a control group, a low-dose sodium arsenite exposure group and a high-dose sodium arsenite exposure group. Sodium arsenite was administered by adding it to drinking water for 3 months. Then, the spatial memory of the rats was examined with Morris water maze and Y maze. The concentration of arsenic in the blood and the brain was determined by an atomic fluorescence absorption spectrometer. The ultra-structure of hippocampal neurons was observed by an electron microscope. Timm staining was used for observing mossy fibers. We found that the concentration of arsenic in the blood and the brain increased in a dose-response manner (P<0.05). The performance of rats in the arsenite exposed group (15 mg/kg) was significantly impaired in the Morris water maze and Y maze tasks than those in the control group (P<0.05). Sodium arsenite exposure resulted in abnormal structural changes in the myelin sheaths of nerve fibers and decreases in the terminals of mossy fibers. Together, chronic sodium arsenite exposure through drinking water results in detrimental changes in the neuronal synapses, which may contribute to the arsenite-induced impairment of spatial memory.
authors: Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China.
authors: Jinfei
authors: J
authors: Jing
authors: Gang
authors: G
authors: Zheng
authors: Mingchao
authors: M
authors: Liu
authors: Xuefeng
authors: X
authors: Shen
authors: Fang
authors: F
authors: Zhao
authors: Jiye
authors: J
authors: Wang
authors: Jianbin
authors: J
authors: Zhang
authors: Guanpeng
authors: G
authors: Huang
authors: Peng
authors: P
authors: Dai
authors: Yinglei
authors: Y
authors: Chen
authors: Jingyuan
authors: J
authors: Chen
authors: Wenjing
authors: W
authors: Luo
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D020261:Arsenic Poisoning / Q000150:complications* / Q000209:etiology; D018053:Arsenites / Q000378:metabolism / Q000633:toxicity; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000473:pathology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008569:Memory Disorders / Q000209:etiology* / Q000473:pathology*; D046529:Microscopy, Electron, Transmission; D019599:Mossy Fibers, Hippocampal / Q000473:pathology / Q000648:ultrastructure; D009474:Neurons / Q000187:drug effects / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013037:Spatial Behavior / Q000187:drug effects; D013569:Synapses / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D013997:Time Factors
chemical_list: D018053:Arsenites; C015001:arsenite