细叶远志皂苷对阿尔茨海默病大鼠海马低密度脂蛋白受体相关蛋白1水平的影响

Effect of Tenuigenin on low density lipoprotein receptor-related protein 1 level changes of Alzheimer's disease rat in hippocampus

目的探讨细叶远志皂苷（TEN）对阿尔茨海默病（AD）大鼠海马低密度脂蛋白受体相关蛋白1（LRP1）水平的影响。方法 60只SD大鼠随机分组,采用脑立体定位技术将β-淀粉样蛋白（Aβ）1~40注入大鼠右侧海马CA1区制备AD模型并给予细叶远志皂苷治疗4周。术后分别采用Morris水迷宫、Real-time PCR和Western blotting检测大鼠学习记忆能力及海马内LRP1 mRNA及蛋白的表达变化,并行免疫荧光检测海马区LRP1阳性神经元的变化。结果 1.Morris水迷宫：模型组大鼠学习记忆能力较正常组相比明显降低（P〈0.01）,经TEN灌胃治疗后,TEN各剂量组逃逸潜伏期均不同程度缩短、游泳路程缩小、穿越虚拟平台次数增加,中、高剂量组差异具有统计学意义（P〈0.05,P〈0.01）;2.Real-time PCR和Western blotting：模型组LRP1mRNA和蛋白的相对表达量均明显低于正常对照组（P〈0.01）,给予TEN治疗后,治疗组LRP1mRNA和蛋白相对表达量随着TEN给药剂量的增加逐步升高,低剂量组差异不明显（P〉0.05）,中、高剂量组与模型组之间的差异有统计学意义（P〈0.01）;3.免疫荧光检测结果显示,海马区模型组LRP1阳性细胞明显减少,与正常组差异有统计学意义（P〈0.01）;高剂量组LRP1阳性细胞数量增加明显,与正常组差异没有统计学意义（P〉0.05）。结论细叶远志皂苷可能通过提高脑内LRP1的含量,从而改善Aβ1~40诱导的AD大鼠的学习记忆能力。

Objective To observe the effect of Tenuigenin（ TEN） on low density lipoprotein receptor-related protein 1（ LRP1） level in Alzheimer’s disease（ AD） rat hippocampus. Methods Sixty SD rats were randomly divided into groups respectively. β-Amyloid protein（ Aβ）1-40 was injected into hippocampus CA1 region to establish AD model by brain stereotactic technique and then rats were treated with intragastric TEN for four weeks. Learning and memory abilities were assessed by Morris water maze and the Real-time PCR and Western blotting were used to analysis the expression of LRP1 mRNA and protein. The changes of LRP1 positive neurons were checked by immunofluorescence staining. Results1. Morris water maze： the learning and memory ability of the AD group was significantly decreased than that of the normal group（ P 〈 0. 01）. After TEN gastric lavage treatment,the escape latency was shortened,the swimming distance was reduced,and the frequency of the virtual platform was increased in every TEN treatment group,there were a statistically significant difference in middle and high dose group（ P 〈 0. 05 or P 〈 0. 01）. 2. Real-time PCR and Western blotting： the relative expression levels of LRP1 mRNA and protein in AD group were significantly lower than that in normal control group（ P 〈 0. 01）. After TEN treatments,the relative expression of LRP1 mRNA and protein in the treatment group increasedgradually with the increase of the dosage of TEN. The effect of low dose group was not significant（ P 〉 0. 05）,but there were a significant difference between middle and high dose groups（ P 〈 0. 01）. 3. Compared with normal group,the number of LRP1 positive cells in the AD group decreased significantly（ P 〈 0. 01）,but in the high dose group increased significantly（ P 〉 0. 05）. Conclusion TEN may improve the learning and memory ability of Aβ1-40 induced AD rats by increasing the content of LRP1 in the brain.