中文摘要：

为明确极低频电磁场（ELF-EMFs）的神经生物效应,研究了ELF-EMFs曝露对大鼠认知功能和海马形态结构的影响.首先将雄性Wistar大鼠放在ELF-EMFs（50Hz、400μT、〈1V/m）中连续曝露60d,实验期间,每周记录大鼠的体质量。终止曝露后,采用Morris水迷宫实验检测大鼠的认知功能。最后采用光镜和电镜观察海马组织结构,并通过甲苯胺蓝染色和图像分析检测尼氏体含量。结果表明：大鼠体质量的增长速度于曝露期间显著延缓,终止曝露2周后恢复;大鼠的平均逃避潜伏期于终止曝露后即刻显著延长（P〈0.01）,7d后恢复。终止曝露后即刻可观察到部分海马神经元发生变性、早期凋亡、突触结构破坏,尼氏体含量减少（P〈0.05）;终止曝露后15d,上述病变改善,30d后恢复。以上结果表明,极低频电磁场曝露（50Hz,400μT,60d）会导致大鼠体质量增长速度延缓、认知功能障碍、海马结构损伤及尼氏体含量减少;以上影响主要发生于终止曝露后早期,并具有持续时间较短暂且可恢复的特点。

英文摘要：

In order to define the neurobiological effects of extremely low frequency electromagnetic fields（ELF-EMFs）,the cognitive function and hippocampal morphology of rats exposed to ELF-EMFs were experimentally investigated.Some male Wistar rats were exposed to ELF-EMFs（50 Hz,400 μT,1 V/m） for 60 d firstly,meanwhile these body weights were recorded weekly.After the exposure,the cognitive function,hippocampal morphology and content of Nissl bodies were measured by Morris water maze test,light/electronic microscopy and toluidine blue staining image analysis,respectively.The results showed that,during the exposure,the growth rate of rat body weight significantly decreased,but it restored after stopping exposure for 2 weeks.Immediately after the exposure being stopped,the average escape latency was significantly prolonged（P0.01）,but it restored 7 d later.Part of the rat hippocampal neurons showed characteristic morphological changes of degeneration and apoptosis,and damages in synaptic structural,and the content of Nissl bodies reduced（P0.05）;however,the lesions mentioned above recovered 15 d later and even restored 30 d later.It is concluded that the ELF-EMFs exposure（50 Hz,400 μT,60 d） can decrease the growth rate of body weight,cause cognitive dysfunctions,damage hippocampal formations,and reduce the content of Nissl bodies.However,these effects occur mainly in the early stage after the exposure being stopped,thus they were characterized by short duration and recoverability.