Semaphorin-3A与苔藓纤维出芽在毛果芸香碱致痫大鼠中的改变及意义

Change and Significance of Semaphorin-3A and Mossy Fiber Sprouting in Epileptic Rats Induced by Pilocarpine

目的探讨海马Semaphorin-3A(Sema3A)与苔藓纤维出芽(MFS)在癫痫发病机制中的作用。方法通过小剂量多次腹腔注射氯化锂-毛果芸香碱建立癫痫大鼠模型,随机将大鼠分为生理盐水对照组和痫性发作组。痫性发作组分别于药物注射后1、5、7d及3、4周时间点,应用Western blotting法检测大鼠海马Sema3A的表达,同时采用neo-Timm银染观察海马MFS情况。结果生理盐水对照组Sema3A仅有少量表达,痫性发作组1、5d无表达,7d表达明显,3周后亦无表达;痫性发作组1、5d未见MFS,7d可见MFS至齿状回内分子层,3周后明显可见MFS至齿状回分子层。痫性发作组Timm评分与生理盐水对照组比较差异有统计学意义(P<0.05)。结论海马区Sema3A表达变化伴有MFS可能是癫痫发病机制的重要因素之一。

Objective To investigate possible roles of Semaphorin 3A （Sema3A） and mossy fiber sprouting （MFS） in the hippocampus of epileptic rats. Methods Small doses of lithium chloride piloearpine were used to establish epileptic models by intraperitoneal injection repetitively. Rats were divided into normal saline treated control group and seizure group. After the last injection of pilocarpine, brain tissues were collected at 1 day, 5 days, 7 days, 3 weeks and 4 weeks. The extractions from hippocampal tissues were used to detect the expression of Sema3A by western blotting. Meanwhile, neo Timm silver staining of the hippocampus was used to observe MFS. Results Comparing with datas from the control group, the protein levels of Sema3A were increased significantly at 7 days in seizure group. However at 1 day, 5 days, 3 weeks and 4 weeks, there was no expression of Sema3A. In the seizure group, there was no MFS at 1 day and 5 days. A small amount of MFS was observed in the inner molecular layer of the dentate gyrus at 7 days. MFS was in the molecular layer of the dentate gyrus after 3 weeks in seizure group. Timm scores of the seizure group were higher than control group （χ^2 = 12. 675, P = 0. 013）. Conclusions Change of Sema3A with MFS may be an important factor in the pathogenesis of epilepsy.