荧光金逆行示踪观察匹罗卡品致痫大鼠CA1区锥体细胞突触联系变化的研究

Changes of synaptic connections among pyramidal cells in the CA1 area of pilocarpine-induced epileptic rats observed by fluorogold

目的通过荧光金（FG）逆行示踪观察氯化锂-匹罗卡品致痫模型大鼠慢性自发发作期海马CA1区锥体细胞之间的突触联系变化。方法 SD大鼠2 0只随机分为实验组和对照组。癫痫持续状态后6 0 d左右,利用立体定位仪在活体内注射逆行性示踪剂FG至海马CA1区,术后常规喂养5~7 d后灌注取材。激光扫描共聚焦显微镜下观察FG的分布。结果 7只实验组大鼠中有5只可见有FG标记的锥体细胞,对照组未见。实验组中有2只大鼠在海马下托亦可见有FG标记的锥体细胞,而对照组未见。结论颞叶癫痫大鼠海马CA1区锥体细胞之间和下托至CA1区有异常兴奋性突触联系,其可能是构成异常兴奋性回路的解剖学基础。

Objective In this study,we used fluorogold（FG） to observe the synaptic connections among pyramidal cells in the CA1 area of the hippocampus in pilocarpine-induced epileptic rats at the chronic phase.Methods Twenty SD rats were randomly divided into epilepsy（n=10） and control（n=10） groups.The models of epilepsy were established by intraperitoneal injections of pilocarpine and lithium.The controls were injected with normal saline.About 60 days after status epilepticus（SE）,retrograde tracer FG was injected into the CA1 area of the hippocampus in vivo by using the stereotaxic apparatus.After surgery,animals were allowed to survive for 5-7 days before perfusion-fixation.Confocal microscopy was used to observe the distribution of FG.Results Additional FG-labeled pyramidal cells were seen remote from the zone of dye spread in the CA1 area in five rats of the epilepsy group,and also additional FG-labeled pyramidal cells were seen in the subiculum in two experimental rats;additional FG-labeled pyramidal cells were not seen in the control group.Conclusions Aberrant synaptic connections among pyramidal cells in CA1 area and aberrant connections of pyramidal cells between CA1 area and subiculum in the hippocampus might be an anatomy basis forming the aberrant excitatory circuit in rats with temporal lobe epilepsy.