托吡酯对癫痫大鼠海马神经元超微结构及bcl-2表达的影响

目的观察托吡酯对癫痫大鼠海马神经元超微结构及bcl-2表达的影响,以探讨托吡酯可能的神经保护机制。方法将大鼠随机分为正常对照组、海人酸组(KA)和托吡酯预处理组(TPM)。采用海人酸腹膜腔注射制作癫痫持续状态(SE)模型。在SE模型制作前,TPM组大鼠用TPM(18mg/(kg·d))灌胃15d,同时用等量生理盐水给KA组大鼠灌胃。正常对照组大鼠不作任何处理。在痫性发作终止后6、24、48h取海马,电镜观察神经元的超微结构,免疫组化方法检测bcl-2的表达。结果KA组神经元呈凋亡特征。TPM组神经元结构大致正常,但出现核仁边聚和细胞器增多现象,亦观察到少量凋亡神经元。KA组于SE后6h观察到bcl-2表达增高(与对照组相比,P<0.05),于24h开始减弱,48h仅有微弱表达。TPM组在24h点有bcl-2的强表达(P<0.001),并持续至48h。结论托吡酯预处理能减轻癫痫大鼠神经元的损伤,其神经保护作用可能与bcl-2蛋白的表达上调有关。

Effects of Topiramate on neuronal ultrastructure and bcl-2 expression in hippocampus of epileptic rats

Objective To observe the effects of Topiramate (TPM) on the neuronal ultrastructure and bcl-2 expression in hippocampus of epileptic rats, in order to explore possible mechanisms of neuroprotective effect of Topiramate.Methods Forty-two SD rats were randomly assigned into three groups: blank control group (n=6), kanic acid (KA) group and TPM group (n=18 each). A model of status epilepticus (SE) was induced by intraperitoneal injection of KA (10 mg/kg). Before preparation of the model, the TPM group received intragastric administration of TPM (18 mg/kg daily) for 15 days; normal saline of equal volume was administered to the KA group. The blank control group did not received any treatment. 6, 24 and 48 hrs after SE, the rats were sacrificed and the hippocampus were removed. The neuronal ultrastructure was observed under an electron microscope, and immunohistochemical staining was used to examine the protein level of bcl-2.Results The neurons of the KA group showed characteristics of apoptosis. The neuronal ultrastructures of the rats from the TPM group were nearly normal, nucleole margination and increment of both Golgi body and lysosome were observed. Few apoptotic neurons were noted in the TPM group. In the KA group, the expression of bcl-2 increased 6 hrs after SE (compared with the blank control group, P<0.05), but began to decrease at 24 hrs, and only a weak expression was detected at 48 hrs. The expression of bcl-2 in the TPM group increased at 6 hrs, peaked at 24 hrs and remained a higher level until 48 hrs.Conclusions Pretreatment with TPM could reduce neuronal injury in epileptic rats. The neuroprotection might be related to the up-regulation of bcl-2 expression.