颞叶癫痫大鼠学习记忆障碍与海马区PSD-95表达的关系

Relationship between deficits for learning memory in temporal lobe rats and expressions of PSD-95 in hippocampus

目的研究颞叶癫痫大鼠在Morris水迷宫中学习、记忆能力与大鼠海马区PSD-95表达变化的关系。方法随机将40只W istar大鼠分为海人酸(KA)组(28只)和对照组(12只)。KA组采用KA腹腔注射制作颞叶癫痫大鼠模型,根据是否出现自发性再发作(SRS)分SRS组(A组)、无SRS组(B组);对照组(C组)注射生理盐水。通过Morris水迷宫测验观察各组大鼠注射KA或生理盐水2、6周时的空间学习、记忆能力,采用HE染色观察大鼠海马的组织病理学变化,免疫组化法检测大鼠海马CA1、CA3区PSD-95的表达。结果A组大鼠注射KA或生理盐水6周时海马区未见广泛神经元丢失及胶质增生,偶见局部神经元丢失及胶质增生;B、C组大鼠未见神经元丢失及胶质增生。与A组2周时及B、C组在2、6周时相比,A组6周时的学习、记忆能力明显下降(P<0.01),相应海马CA1、CA3区PSD-95表达均明显降低(P<0.05)。结论颞叶癫痫长期反复发作时海马区PSD-95表达的减少,可能是导致颞叶癫痫大鼠学习、记忆障碍的机制之一。

Objective To investigate the abilities of the learning and memory in temporal lobe epileptic rats and its relationship with the expression of PSD-95. Methods Forty male Wistar rats were divided randomly into kainie acid （KA） group and control group. The KA group was made by KA through intrapefitoneal injection and the control group by normal saline （NS）. According to developing spontaneous recurrent seizure （ SRS）, the KA group was divided into KA ＋ SRS group （grotlp A） and KA-SRS group （group B）. The control group＇was group C. Then the learning and memory abili- ties of rats were tested by water maze training at 2 and 6 weeks after using KA or NS. The histopathology of hippoeampus of different groups were observed by HE staining. The expression levels of PSD-95 in hippoeampus of the rats of different groups were compared by immunohistochemieal staining. Results No extensive neuronal cell loss and gliosis were noted, and areas of neuronal cell loss and gliosis were occasionally seen in hippocampus at 6 weeks after using KA. No neuronal cell loss and gliosis were noted in hippocampus at 6 weeks after using NS. Compared with those of group A at 2 weeks, and of group B, C at 2 and 6 weeks, the learning and memory abilities of group A at 6 weeks were obviously impaired （P 〈 0.01 ）, and the expression of PSD-95 of group A in hippocampus decreased （ P 〈 0.05 ）. Conclusions The decrease of expression of PSD-95 in hippocampus might result in impairments of learning and memory abilities of temporal lobe epileptic rats.