戊四氮诱发癫痫大鼠海马齿状回颗粒细胞树突发芽

Dendritic sprouting in the hippocampal dentate gyrus granular cells of rats with epilepsy kindled by pentetrazol

目的利用化学点燃大鼠癫痫模型,观察癫痫发作后大鼠海马齿状回颗粒细胞树突的形态学变化,探讨癫痫敏感性形成机制。方法利用戊四氮(PTZ)制作化学点燃大鼠癫痫模型。采用点燃成功后3d、7d两个时间点,应用神经元高尔基染色法,在光镜下观察和定量分析大鼠海马齿状回颗粒细胞的树突改变。结果颗粒细胞的形态学参数(树突总长度、树突分支点数、树突野最大伸展距离和树突棘密度)在PTZ点燃后3d时均显著降低(P<0.05),而在PTZ点燃后7d时明显回升,并明显高于生理水平(P<0.05)。结论在PTZ点燃大鼠癫痫发作后,颗粒细胞树突出现明显的可塑性改变,并在PTZ点燃后7d时出现发芽现象,这可能与癫痫敏感性的形成有关。

Objective To observed the morphology changes in dendritcs of hippocampal dentate gyrus granular cells in rats with epilepsy in order to gain morphological evidences for mechanism of epileptic susceptibility formation.Methods The model of epilepsy was made by intraperitoneal injection of 40 mg/kg pentetrazol （PNT） in 15 rats,who were divided into 3 groups of 5 rats each,i.e.experimental groups 1 and 2,and control group.The rats were sacrificed 3 days （in the experimental group 1） and 7 days （in the experimental group 2） after epileptic seizure kindled by PTZ in order to gain their brain and to observe the morphological changes of dendrites of the hippocampal dentate gyrus granular cells by Golgi staining method.Results The total dendritic length,the number of the dendritic branch,the density of the dendritic spines and the largest transverse spreads of the dendrites in the hippocampal dentate gyrus granular cells were significantly enhanced 7 days after the epileptic seizure kindled by PTZ compared to the control group （P〈0.05）,where they were significantly higher than those 3 days after the epileptic seizure kindled by PTZ （P〈0.05）.Conclusions There is the plasticity in the dendrites of hippocampal dentate gyrus granular cells after epileptic seizure kindled by PTZ and sprouts in the ones 7 d after the epileptic seizure in the rats.It was suggested that the sprouting of the dendrites in the hippocampal dentate gyrus granular cells may be related with increase in the susceptibility of epileptic seizure in the rats.