遗传性癫痫易感大鼠P77PMC海马苔藓状纤维发芽的研究

A study of mossy fiber sprouting in hippocampus of genetically epilepsy prone rats——P77PMC

目的 :研究遗传性癫痫易感大鼠模型——P77PMC大鼠在反复惊厥过程中海马的可塑性变化 ,探讨此模型的癫发生、发展的病理生理机制。方法 :采用Timm硫化银染色法分析P77PMC大鼠在反复听源性惊厥不足10次以及惊厥 2 0次、30次和 5 0次时海马苔藓状纤维 (mossyfiber ,MF)发芽现象。 结果 :在全身性强直阵挛性惊厥发作次数少于 30次的P77PMC大鼠以及对照的Wistar大鼠海马内均未见到MF发芽表现 ;而在经历 5 0次Ⅳ～Ⅴ级听源性惊厥发作的一组P77PMC大鼠海马内观察到了MF发芽的现象 ,在海马齿状回内分子层内见到Timm染色呈棕黑色颗粒异常分布的MF末梢。结论 :不仅边缘脑性惊厥可导致海马MF发芽 ,而且在遗传性听源性惊厥这种脑干起源但迅速泛化为全身性惊厥发作的癫动物模型也有海马内MF突触重组的表现 ;听源性惊厥易感大鼠在经历足够多次的惊厥发作后可发生海马MF发芽 ,即单纯惊厥的反复发作就可导致海马内MF发生突触重组。

SUMMARY Objective: To investigate pathophysiologic mechanism about initiation and propagation of epilepsy in a genetically epilepsy prone rat (GEPR) model. Methods: The hippocampal MF sprouting of P77PMC rats was examined at different stages in the course of recurrent seizures using Timm method of sulfide silver staining. Results:The three groups of P77PMC rats which experienced 30 and less than 30 times of audiogenic seizure ( AGS ) and the Wistar control group did not display MF sprouting in dentate gyrus, however, the group of P77PMC rats which experienced 50 times of AGS was found hippocampal MF sprouting into the inner molecular layer of dentate gyrus. Conclusion:Our findings suggest that hippocampal MF sprouting presented not only in limbic seizure, but also in AGS, the seizure initiated in brainstem but rapidly generalized; in AGS prone rats, recurrent AGSs can induce MF synaptic reorganization in hippocampus.