匹罗卡品致痫大鼠的海马PV中间神经元数目变化及其轴突出芽☆

Quantitative changes and axonal sprouting of PV positive interneurons in the hippocampus of epileptic rats induced by pilocarpine

目的探讨PV(parvalbumin,微清蛋白)中间神经元在颞叶癫痫的发生和痫性损伤后脑组织的自我修复中的作用。方法建立匹罗卡品致痫模型。免疫组化方法检测各时间点海马不同区域PV中间神经元的数目变化及其轴突出芽情况;结合FJB(Fluoro-Jade B)行免疫荧光双标特异性检测SE(status epilepticus,癫痫持续状态)后60 d海马不同区域PV中间神经元及其轴树突的变性情况。结果实验组海马门区及CA区域PV阳性神经元数目在SE后早期均无明显变化(P>0.05)。门区PV神经元在SE后15 d时数目下降(对照组17.1±2.67,实验组15.0±3.06,P<0.05),在SE后60 d明显下降(对照组16.6±2.75,实验组9.7±2.88,P<0.01)。海马CA1区PV中间神经元数目在SE后60 d明显增多(对照组4.1±0.86,实验组6.0±1.18,P<0.01),可见相应增多的PV阳性纤维。海马CA3区PV阳性神经元数目在SE后60d明显增多(对照组4.6±0.89,实验组6.1±1.64,P<0.01),并可见相应增多的PV阳性纤维。各亚区均未见明显亦被FJB标记的PV中间神经元。结论海马PV中间神经元的数目变化及其轴突出芽可能在颞叶癫痫的发生和痫性损伤后脑组织的自我修复中起重要作用,PV中间神经元的缺失可能与细胞变性死亡无关。

Objective To investigate the roles of PV positive interneurons in the generation of temporal lobe epilepsy and the compensation of the brain tissue after seisures. Methods Pilocarpine-induced animal model was founded. Immunohistochemistry method was used to detect number changes and axonal sprouting of PV positive interneurons in different domains of the hippoeampus at different time points. Degeneration of PV positive interneurons and their neurophils on 60d after epileptic status（SE） was detected by the technique of double immunofluoreseence combined with FJB. Results No significant changes of PV-IR neurons was present in the hilus and CA regions in the acute and resting phase（P 〉 0. 05）. The number of hilar PV-IR neurons decreased at 15days post-SE （ control 17.1 ± 2. 67, post-SE 15.0 ± 3.06, P 〈 0. 05 ） , and decreased significantly at 60days post-SE（ control 16. 6 ± 2. 75,post-SE 9.7 ± 2. 88 ,P 〈 0. 01 ）. PV-IR neurons in CA1 region increased significantly at 60days post-SE（ control 4. 1 ±0. 86,post-SE 6. 0± 1.18, P 〈 0. 01 ）, and increased PV-IR fibers were also observed. PV-IR neurons in CA3 region increased significantly at 60days post-SE （ control 4. 6 ± 0. 89,post- SE 6. 1 ± 1.64,P 〈0. 01 ） , with correspondingly increased PV-IR fibers also seen. We examined PV-IR and FJB doublestaining in serial sections at 60d post-SE. Double-immunofluorescenee revealed there were no neurons double-labeled for Fluoro-Jade B and PV in each subfield. Conclusions Quantitative changes of PV interneurons and their axonal sprouting may play an important role in the generation of temporal lobe epilepsy and the compensation of the brain tissue after seizures, loss of PV interneurons may be not due to the cell＇s degeneration and death.