黄精多糖对慢性脑缺血大鼠学习记忆能力及脑组织超微结构影响

Effects of Polygonatum Polysaccharides on Learning and Memory and Ultrastructure Changes of Brain Tissue in Rats with Chronic Cerebral Ischemia

目的:通过观察黄精多糖对慢性脑缺血大鼠学习记忆能力及脑组织超微结构影响,评价黄精的抗衰老作用并探讨其机制。方法:雄性SD大鼠32只,按随机数表随机分为4组:假手术对照组、模型组、黄精多糖组、阳性药物对照组,每组8只。采用二血管闭塞法制备脑缺血模型,假手术组、模型组:灌胃生理盐水,黄精多糖组:造模术后24 h开始灌胃黄精多糖2 mL/kg·d^(-1),阳性药物对照组:灌胃尼莫地平按10 mg/kg,均1次/日,连续灌胃8周。第8周,Morris水迷宫检测大鼠学习记忆能力;尼氏染色检测海马神经元损伤;电镜观察脑组织超微结构变化。结果:1)Morris水迷宫实验结果:黄精多糖组较模型组平均逃避潜伏期明显缩短(P<0.05),穿台次数增多(P<0.05),黄精多糖组和阳性对照组之间差异无显著性差异(P>0.05)。2)尼氏染色显示:模型组前额皮质和海马区神经元内尼氏体阳性神经元明显减少,染色较浅,黄精多糖组较模型组尼氏体阳性神经元数目明显增多,与阳性对照组比较无显著性差异(P>0.05)。3)电镜观察结果:模型组大鼠大脑皮层、海马CA1区神经细胞肿胀,线粒体嵴断裂,细胞轮廓模糊,细胞核固缩,核膜内陷,锯齿样变;黄精多糖组胞浆内细胞器丰富,仅偶见内质网肿胀,毛细血管壁稍有肿胀,偶见少量染色质凝集,高尔基体丰富;阳性对照组电镜下观察与黄精多糖组相似,表现线粒体肿胀轻微,线粒体嵴断裂更加少见,未见有核膜内陷。结论:黄精多糖可改善慢性脑缺血大鼠学习记忆能力,减轻大脑超微结构损伤。

Objective：To observe the effects of Polygonatum Polysaccharides on learning and memory and brain tissue ultrastructure changes in rats with chronic cerebral ischemia,evaluate the anti - aging mechanisms of Polygonatum Polysaccharides.Methods：32 male SD rats were randomly divided into 4 groups,sham operated group,chronic cerebral ischemia group,Polygonatum Polysaccharides group and Nimodipine group,models were built by ligation of common carotid artery.Sham operated group and chronic cerebral ischemia group：were Ig 0.5 mL normal saline; Polygonatum Polysaccharides group：twenty - four hours after operation,2 mL/kg ＆#183; d - 1 Polygonatum Polysaccharides dissolved in 0.5 mL normal saline was administered orally once daily; Nimodipine group：twenty- four hours after operation,Nimodipine was administered orally 10 mg/kg for once daily,each group was given the corresponding medicine or saline for 8 weeks.Morris water maze was used to detect the learning and memory ability of rats,and the damage of hippocampal neurons was detected by Nissl staining.The ultrastructure changes of brain tissue was observed by electron microscope.Results：1 ） The average escape latency of rats in Polygonatum Polysaccharides group was significantly shorter than that of the model group （ P 〈 0.05）,and there was no significant difference between Nimodipine group and Polygonatum Polysaccharides group.2） Positive neurons decreased significantly in the prefrontal cortex and hippocampus in model group and increased in Polygonatum Polysaccharides group,and there was no difference between the Polygonatum Polysaccharides group and Nimodipine group.3）Cell swelling,mitochondrial crest fracture,cell contour,nuclear condensation and nuclear membrane invagination were seen by electron microscopy in model group,however,rich cell organelle,few endoplasmic reticulum swelling,capillary wall swollen,chromatin agglutination were seen in Polygonatum Polysaccharides group;the images of Nimodipine group were similar to Polygonatum Polysaccharides group.Conclusion：Polygonatum Polysaccharides could improve the ability of learning and memory by reducing the damage of neuron of rats.