棘突形态及功能重塑在癫痫形成中的研究

目的 研究癫痫形成过程中棘突形态、功能变化以及棘突重塑在癫痫形成过程中的可能作用.方法 ①20只SD大鼠随机数字表法分为癫痫组及对照组,建立锂-匹罗卡品慢性癫痫模型,高尔基染色观察大鼠海马齿状回棘突形态变化,qRT-PCR及Western blot检测海马PSD95及SYP表达变化.②选择SD胎鼠海马神经元进行原代培养,建立无镁癫痫模型.检测细胞内钙离子浓度及神经元棘突数量变化情况统计两者相关性.结果 ①与对照组相比,癫痫模型组大鼠齿状回(dentate gyrus,DG)区棘突平均密度增加,但正常功能棘突数量减少,PSD95及SYP表达增加(P＜0.01)②癫痫组细胞内钙离子浓度增加(P＜0.01),且与神经元棘突密度变化呈正相关(r=0.613,P＜0.05).结论 癫痫形成过程中突触重塑活跃.但形态及功能异常,为癫痫形成提供基础,可作为棘突重塑的重要标志.

Changes of dendritic spine morphology and functions in the development of epilepsy in rats

Objective To investigate the morphological and functional changes of dendritic spines during the development of epilepsy and explore the possible role of dendritic spine remodeling in epilepsy.Methods Twenty SD rats were randomly divided into control group and epilepsy group,and in the latter group,rat models of chronic epilepsy were established by intraperitoneal injection of lithium and pilocarpine.The morphology of the dendritic spines of the neurons in the hippocampal dentate gyrus (DG) was observed using Golgi staining,and the changes in the expression levels of postsynaptic density protein 95 (PSD95) and synaptophysin (SYP) were detected using qRT-PCR and Western blotting.Hippocampal neurons were isolated from fetal SD rats for primary culture,and an epileptic cell model was established using magnesium-free medium.The changes in intracellular calcium concentration and the density of dendritic spines were assessed in the cells after modeling.Results Compared with the control rats,the epileptic rats showed significantly increased mean density of dendritic spines in the DG neurons (P ＜ 0.05) with reduced mushroom-shaped spines (P ＜ 0.05);The expression of PSD95 and SYP in the hippocampus was significantly increased in the epileptic rats (P ＜ 0.05).In the hippocampal neuronal model of epilepsy,intracellular calcium concentration increased significantly after modeling compared with that in the control cells (P ＜ 0.01) and showed a significant positive correlation with the density of dendritic spines in the neurons (P ＜ 0.05).Conclusion Synaptic remodeling is super-active during epilepsy with morphological and functional abnormalities of the synapses,which provides the pathological basis for epilepsy and serves as an important sign of dendritic spine remodeling.