Perinatal exposure to low-dose methylmercury induces dysfunction of motor coordination with decreases in synaptophysin expression in the cerebellar granule cells of rats
- 作者：Masatake Fujimuraa ; fujimura@nimd.go.jp ; Jinping Chengb ; Wenchang Zhaob
- 关键词：MeHg ; methylmercury ; CNS ; central nervous system ; PND ; postnatal day ; SPP ; synaptophysin ; Hg ; mercury ; IP3R1 ; 1 ; 4 ; 5-trisphosphate receptor type 1 ; GD ; gestation day ; PBS ; phosphate-buffered saline ; H&E ; hematoxylin and eosin ; GFAP ; glial fibrillary acidic
- 刊名：Brain Research
- 出版年：2012
- 期刊代码：8_00068993
- 类别：neu
- 出版时间：29 June, 2012
- 卷：1464
- 期：Complete
- 页码：1-7
- 文件大小：1174 K
摘要
Methylmercury (MeHg) is an environmental pollutant that is toxic to the developing central nervous system (CNS) in children, even at low exposure levels. Perinatal exposure to MeHg is known to induce neurological symptoms with neuropathological changes in the CNS. However, the relationship between the neurological symptoms and neuropathological changes induced in offspring as a result of exposure to low-dose MeHg is not well defined. In the present study, neurobehavioral analyses revealed that exposure to a low level of MeHg (5 ppm in drinking water) during developmental caused a significant deficit in the motor coordination of rats in the rotating rod test. In contrast, general neuropathological findings, including neuronal cell death and the subsequent nerve inflammation, were not observed in the region of the cerebellum responsible for regulating motor coordination. Surprisingly, the expression of synaptophysin (SPP), a marker protein for synaptic formation, significantly decreased in cerebellar granule cells. These results showed that perinatal exposure to low-dose MeHg causes neurobehavioral impairment without general neuropathological changes in rats. We demonstrated for the first time that exposure to low-dose MeHg during development induces the dysfunction of motor coordination due to changes of synaptic homeostasis in cerebellar granule cells.