产后母仔分离4周对小鼠海马神经可塑性及睡眠行为异常的影响

Effects of postpartum maternal separation of four weeks on hippocampal neuroplasticity and abnormal sleep behavior in mice

目的本研究旨在探究出生后母仔分离的小鼠是否在青春期时出现睡眠行为的异常和脑内海马区神经可塑性的改变。方法本实验选取雌雄共12只C57 BJ/6 L小鼠繁殖交配生仔后进行母婴分离28 d进行造模。在模型构建后对所有青春期小鼠进行手术埋置电极记录海马区的脑电图,并且根据波形监测小鼠的清醒/睡眠活动。快速制备海马组织切片,进行脑片电生理检测,诱导LTP的形成,观察小鼠的突触可塑性的变化。另外,对小鼠海马取材进行免疫荧光染色和高尔基染色,观察海马区域神经元树突棘的形态和密度是否发生改变。最后,免疫印迹法检测与神经发生、发育、营养支持相关的Nestin、Sox2、MAP-2和GFAP的蛋白质水平,探究母婴分离对小鼠造成神经系统损伤的分子机制。结果母婴分离小鼠的睡眠结构出现改变,白天清醒时间更长,夜晚睡眠过程中快速动眼睡眠和非快速动眼睡眠的比例发生改变。对照组小鼠可以诱导正常的LTP,而母婴分离小鼠形成的LTP中fEPSP斜率随时间逐渐降低,整体FV振幅较对照组降低。海马神经元的树突棘密度降低。Nestin,Sox2,MAP-2等分子在母婴分离组小鼠海马脑区中的表达均出现下降,差异均有统计学意义。结论产后母婴分离小鼠在青春期时表现出睡眠行为的障碍以及海马区神经元突触可塑性的下降。

Objective To explore whether maternal separation after birth have abnormal sleep behavior and changes in neuronal plasticity in the hippocampus during adolescence.Methods In this project,a total of 12 male and female C57 BJ/6 L mice(1∶2)were selected for breeding and mating,and then the mother and infant were separated for 28 days for modeling.All adolescent mice were surgically embedded with electrodes to record the EEG of the hippocampus,and the wake/sleep activities of the mice were monitored based on the waveform.Preparing acute hippocampal tissue slices and inducing the formation of LTP to observe changes in synaptic plasticity in mice.In addition,immunofluorescence staining and Golgi staining were performed on the mouse hippocampus to observe the dendrites in the synapses of neurons in the hippocampus.Finally,molecules related to neurogenesis,development and supporting such as Nestin,Sox2,MAP-2 and GFAP were detected through Western blot and explore the molecular mechanism of effects causing by maternal separation.Results The sleep structure of the separated mother-infant mice was changed.During the day,they were awake and rested.During the night,the ratio of REM sleep and non-REM sleep were changed.Normal LTP could be induce in normal control group,and the result of maternal and infant neuron staining showed that the dendritic spine density of hippocampal neurons was significantly reduced.Western blot result showed that the expression of Nestin,Sox2,MAP-2,GFAP and other molecules in the hippocampus of the experimental group was decreased.Conclusion The mice suffered from maternal separation after birth showed disturbances in sleep behavior and decreased neuronal plasticity in the hippocampus during adolescent phase.