人参皂苷Rb1对阿尔茨海默病模型小鼠术后认知功能、海马内突触后致密蛋白-95及尼氏体表达的影响

Effects of Ginsenoside Rb1 on Postoperative Cognitive Function,Expression of PSD-95 and Nissl Body in Hippocampus of Alzheimer′s Disease Model Mice

目的观察人参皂苷Rb1对APPswe/PS1dE9双转基因阿尔茨海默病(AD)模型小鼠肝叶部分切除术后认知功能及海马内突触后致密蛋白-95(postsynaptic density protein-95,PSD-95)、神经元尼氏体表达的影响。方法将3月龄AD模型小鼠120只随机分为3组,手术组(S组)于麻醉后行肝叶部分切除术;人参皂苷Rb1组(Rb1组)于手术前5 d腹腔注射人参皂苷Rb160 mg/kg;对照组(N组)于手术前5 d腹腔注射同体积的生理盐水。以上各组随机抽取8只小鼠采用水迷宫连续训练5 d并检测术后1 d、3 d、7 d、14 d、21 d、28 d的学习记忆能力,余小鼠术后3 d、7 d、14 d、21 d、28 d取标本,行尼氏染色并检测海马内PSD-95的表达。结果与Rb1组比较,S组和N组术后3 d、7 d、14 d、21 d、28 d平均逃避潜伏期延长(P<0.05);Rb1组术后目的象限时间百分比较S组和N组升高(P<0.05)。与Rb1组比较,S组和N组术后3 d、7 d、14 d、21 d、28 d PSD-95蛋白表达逐渐减少(P<0.05)。尼氏染色显示:Rb1组术后海马CA1区神经细胞排列密集、整齐,胞浆中尼氏体丰富;与Rb1组比较,S组和N组术后21 d、28 d神经元尼氏体减少(P<0.05)。结论人参皂苷Rb1可以提高AD模型小鼠肝叶部分切除术后的学习记忆能力,其机制可能与其改善突触相关蛋白PSD-95及神经元尼氏体的表达相关。

Objective To observe the effects of Ginsenoside Rb1 on cognitive function,expression of postsynaptic density protein-95(PSD-95)and nissl body in hippocampus of APPswe/PS1dE9 double transgenic Alzheimer′s disease(AD)model mice after partial liver lobectomy.Methods One hundred and twenty 3-month-old APPswe/PS1dE9 double transgenic AD model mice were randomly divided into three groups:surgical group(S group):partial liver lobectomy after anesthesia;Ginsenoside Rb1 group(Rb1 group):intraperitoneal injection of ginsenoside Rb160 mg/kg in the morning 5 days before surgery;control group(N):intraperitoneal injection of the same volume of normal saline in the morning 5 days before surgery.Eight mice were randomly selected from the above groups for continuous training with morris water maze for 5 d and their learning and memory ability were detected at 1 d,3 d,7 d,14 d,21 d,and 28 d after surgery.Specimens were taken from the remaining mice at 3 d,7 d,14 d,21 d,and 28 d after surgery,and the expression of PSD-95 in hippocampus was detected by Nissl staining.Results Compared with Rb1 group,the average latency of escape was prolonged at postoperative 3 d,7 d,14 d,21 d,and 28 d in group S and group N(P<0.05).The percentage of postoperative objective quadrant time in group Rb1 was wore than that in group S and group N(P<0.05).Compared with Rb1 group,PSD-95 protein expression in group S and group N was decreased gradually at 3 d,7 d,14 d,21 d,and 28 d after surgery(P<0.05).Nissl′s staining showed that nerve cells in the hippocampal CA1 region of Rb1 group were arranged densely and neatly,and there were abundant nissl bodies in the cytoplasm.Compared with Rb1 group,the number of neurons in group S and group N was decreased at 21 and 28 days after surgery(P<0.05).Conclusion Ginsenoside Rb1 can improve the learning and memory ability of AD model mice after partial liver lobectomy,and the specific mechanism may be related to the improvement of the expression of synapse related protein PSD-95 and nissl body.