黄精多糖对阿尔茨海默病模型小鼠学习记忆力影响及作用机制研究

目的 探讨黄精多糖对实验性阿尔茨海默病(AD)小鼠的疗效及作用机制.方法 26只淀粉样前体蛋白(amyloid precursor protein,APP)转基因AD小鼠随机分为高剂量组9只、低剂量组9只和模型组8只,每天分别采用16%及4%的黄精多糖溶液1 ml和饮用自来水1 ml灌胃1次,连续45 d;采用Morris水迷宫法测试小鼠的主动学习记忆能力,光镜观察小鼠大脑海马结构,免疫组织化学染色检测海马组织β淀粉样蛋白(Ap)含量和乙酰胆碱转移酶(CHAT)活性.结果 高剂量组、低剂量组与模型组比较:(1)逃避潜伏期缩短,第7天分别为(26.0±9.4)s、(31.2±8.7)s和(39.3±10.9)s,P＜0.05;(2)120 s内穿越隐匿平台位置的次数增多,分别为(5.28±0.76)次、(3.00 ±0.77)次和(1.00±0.63)次,差异有统计学意义(P＜0.01);(3)120 s内在目标象限(第4象限)游泳时间明显延长,分别为(75.50±8.39)s、(51.39±11.99)s和(36.87±1.25)s,差异有统计学意K(P＜0.05),且高剂量均优于低剂量(P＜0.05);(4)治疗组海马组织中ChAT活性增高,Aβ含量减少(P＜0.01),且高剂量组优于低剂量组(P＜0.05);(5)高剂量组、低剂量组神经元数目较多、细胞改变不明显、分布规则;模型组神经元数目明显减少,且可见部分神经元细胞核有固缩状态、细胞变性、凋亡.结论 黄精多糖可减少AD小鼠大脑海马组织中Aβ沉积和增加ChAT的活性,显著改善AD小鼠的学习记忆能力,是治疗实验性AD的有效药物.

Effect of polygona-polysaccharose on learning and memorizing ability and its possible mechanism in Alzheimer disease mice

Objective To investigate the effect of polygona-polysaccharose on experimental Alzheimer Disease(AD)mice and its possible mechanism. Methods Twenty-six amyloid precursor protein(APP)transgenic mice were randomly divided into high dosage group(HDG),low dosage group(LDG)and model group(MG)which consisted of 9,9 and 8 mice respectively.1 ml of 16%,4% polygona-polysaccharose solution and 1 ml of drinkable tap water were infused into the mouse stomach in HDG,LDG and MG respectively once a day for 45 days.Morris water maze was used to test the mice's proactive learning and memorizing ability.The morphology of cerebral hippocampus was observed by microscope.The content of amyloid-β-protein(Aβ)and the activity of choline acetyltransferase(ChAT)in the cerebral hippocampus were examined by immunochemical staining method. Results Comparisons among treatment groups(including HDG and LDG)and MG showed:(1)Escape delitescence was shortened[at seventh day:(26.0±9.4)s,(31.2±8.7)s and (39.3±10.9)s,P＜0.05];(2)The frequency of finding the hidden platform within 120 seconds was inereased(5.28±0.76)times,(3.00±0.77)times and(1.00±0.63)times,(P＜0.01);(3)The duration of swimming in objective quadrant(the forth quadrant)within 120 seconds was prolonged [(75.50±8.39)s,(51.39±11.9)s and(36.87±1.25)s,(P＜0.05)].HDG provided better results than those in LDG(all P＜0.05);(4)The activity of ChAT was enhanced and Aβ concentration was decreased for which results mice in HDG showed better than in LDG(all P＜0.05);(5)Morphological study in MG showed the sign of neuron apoptosis such as the reduced number of neuron.the shrinking neuron nuclei,the nucleic membrane being irregular and slightly thickened.However.the neuron in treatment groups were more in number,less transformed and more regularly distrIbuted. Conclusions Polygona-polysaccharose can reduce the accumulation of Aβ in the cerebral hippocampus of AD mice and enhance the activity of ChAT.It can significantly improve the learning and memorizing ability of AD mice and thus proves to be an effective experimental drug for treating AD.