加减薯蓣丸对血管性痴呆大鼠海马突触再生和可塑性影响的研究

The Research on Synaptic Regeneration and Plasticity in Hippocampus Interfered by Modified Dioscorea Pills in VD Rats

[目的]探讨加减薯蓣丸(Modified Dioscorea Pills,MDP)对血管性痴呆(vascular dementia,VD)大鼠学习记忆功能及海马突触再生与突触可塑性的影响。[方法]40只SD大鼠按照随机数字表分为手术组28只及假手术组12只。手术组采用改良双血管阻断(2-vessels occlusion,2-VO)法建立VD模型,术后按随机数字表再分为药物组12只、模型组11只,假手术组仅分离颈总动脉,不结扎。药物组用MDP浓缩汤剂(10g/kg·d)灌胃45d,模型组和假手术组以0.9%氯化钠溶液灌胃,剂量、疗程同药物组。采用水迷宫行为学实验评价各组大鼠智能差异,免疫组化测定海马CA1区突触素(synaptophysin,SYP)、突触后密度蛋白-95(postsynaptic density protein-95,PSD-95)及微管相关蛋白-2(microtubule associated protein-2,MAP-2)表达;透射电镜观察突触超微结构的改变。[结果]与模型组比较,药物组大鼠水迷宫行为学表现明显改善;药物组大鼠海马CA1区SYP、PSD-95、MAP-2蛋白表达明显升高,与模型组及假手术组比较均有统计学差异(P<0.01);电镜下可见模型组大鼠海马CA1区突触间隙模糊,突触前后膜肿胀、空化,难以区分突触前后膜;突触小泡减少,线粒体固缩,内质网脱颗粒。药物组突触数量丰富,结构基本完整,线粒体正常、突触小泡较为丰富。[结论]MDP通过上调突触相关蛋白的表达保护缺血条件下的神经突触,并增强突触可塑性,促进突触再生,从而改善突触的信息传递,是其治疗VD取得临床良效的机制之一。

[Objective] Exploring the influence of learning and memory ability, regeneration and plasticity of synapses in VD rats interfered by Modified Dioscorea Pill（MDP）. [Methods]Forty rats were randomly classified into operated group（including 28 rats） and sham-operated group（including 12 rats）according to random number table. Rats in operated group was subjected to modified 2-vessels occlusion（2-VO） operation to set up VD models,bilateral common carotid arteries of rats in sham-operated group were isolated but not ligated. Rats in operated group were furtherly categorized into drug-treated group（including 12 rats） and model group（including 11 rats） according to random number table. Rats in drug-treated group were gavaged with MDP concentrated decoction（10 g/kg·d） for 45 days, rats in model group and sham-operated group were gavaged with 0.9%Na Cl in same dosage and course. The Morris Water Maze（MWM） behavior experiment was used to evaluate the rats＇ intelligence. The expression of synaptophysin（SYP）, postsynaptic density protein-95（PSD-95） and microtubule associated protein-2（MAP-2） in hippocampus CA1 zone were detected by immunohistochemistry; the synaptic ultrastructural changes were observed with transmission electron microscope（TEM）. [Results] Compared with model group, rats in drug-treated group achieved much better behavior performance than the counterparts in model group. The expression of SYP, PSD-95 and MAP-2 up-regulated in drug-treated group. Compared with model group and sham-operated group, the results of drug-treated group were statistically different（ P〈0.01, P〈0.01）. Observed from TEM, the synaptic gaps in model group were blurred, the anterior and posterior membranes were swelling and cavitating. It was difficult to distinguish between presynaptic and postsynaptic membrane. The number of synaptic vesicles decreased, mitochondrions were pyknosis and got less. Endoplasmic reticulums degranulated. Whereas in drug-treated group, synaptic ultrastructural was basicly integrity, the mitochondria was normal and synaptic vesicles were abundant. [Conclusion] MDP can protect the synapse in ischemic condition and promote synaptic regeneration and plasticity through up-regulating the synapse related protein, improve the synaptic information conduction which underlies its good clinic effect.