匹罗卡品致痫大鼠慢性期海马神经元突触重建的实验研究

Neuronal synaptic reconstruction in hippocampus in chronic phase of pilocarpine-treated rats

目的 探讨颞叶癫痫海马的异常兴奋性与抑制性突触联系变化.方法 建立匹罗卡品致痫大鼠模型,在致痫后60 d左右,利用立体定位仪在活体内注射逆行性示踪剂荧光金（FG）至海马CAI、CA3区,免疫组化方法观察海马异常兴奋性突触联系,免疫荧光双标记法检测NPY中间神经元与FG的共表达,观察海马异常抑制性突触联系.结果 FG注人大鼠海马CA1区,实验组远离注射部位的CA1区、海马CA3区、下托可见FG标记的锥体细胞,实验组CA1区远离注射部位处、CA3区、门区均有FG标记的NPY中问神经元,对照组未见.FG注入大鼠海马CA3区,对照组及实验组CA3区全层、门区锥体细胞均可见大量FG标记,实验组中CA1区部分锥体细胞被FG标记,门区可见双标记的NPY中间神经元,对照组未见.结论 颞叶癫痫大鼠海马慢性期存在异常的兴奋性和抑制性回路重组,包括CAl区锥体细胞之间、下托-CA1区、CA1-CA3区异常的兴奋性联系,以及CA1区中间神经元之间、CA3-CA1区、门区-CA1区、门区-CA3区异常的抑制性神经网络.神经元网络的异常重组町能在颞叶癫痫慢性期的自发发作中起重要作用.

Objective To explore the aberrant formation of excitatory and inhibitory circuit rearrangements of hippoeampus in temporal lobe epilepsy.Methods Pilocarpine-induced animal model was established.At around Day 60 post-modeling,retrograde tracer fluorogold（FG）was injected in vivo into CA1 and CA3 areas of hippocampus by stereotaxic apparatus.Immunohistochemistry of FG was used to observe the aberrant excitatory circuit rearrangements.Double immunofluorescence with NPY（neuropeptide Y）and FG was performed to observe the aberrant inhibitory circuit rearrangements.Results After an iniection of FG into CA1 area.the FG-labeled pyramidal cells could be observed distantly from the zone of dye soread in CA1 area.CA3 area and subiculm.And the FG-labeled non-principal neurons could be seen in stratum oriens of CA1 and hilus in experimental group.Double immunofluorescence revealed that the FG-labeled NPY interneurons were located distantly from the zone of dye spread in CA1 area.CA3 area and hilus in experimental rats.When injection was administered in CA3 area.the FG-labeled pyramidal cells were visible in the whole CA3 area and hilus in both groups.Some pyramidal cells were present in CA1 in experimental group.Also some FG-labeled non-principle cells were foand in hilus and distantly from the zone of dve spread in CA1 area,And the FG-labeled NPY neurons could be seen in hilus in experimental rats.Conclusion Aberrant excitatory and inhibitory synaptic reconstruction exist in hippocampus in chronic phase of temporal lobe epilepsy,including excitatory synaptic connections among pyramidal cells in CA1 area.pyramidal cells between CAl and subiculum and pyramidal cells between CA1 and CA3,inhibitory synaptie connections among dendritie intemeurons in CA1 area,CA3 to CA1,hilus to CA1 and hilus to CA3area,These circuit arrangements may play an important role in the pathogenesis of epilepsy.