【作者】 孙雯雯；

【导师】 刘昕；

【作者基本信息】 兰州大学 ， 病理学与病理生理学， 2012， 硕士

【摘要】 目的：观察高胆固醇血症在阿尔茨海默病(AD)发生中的作用及藏药柳茶提取物的治疗效应。方法：依数字表法将SD大鼠随机分为4组：Ⅰ为正常对照组、Ⅱ为AD模型组、Ⅲ为高胆固醇并AD组、Ⅳ为柳茶治疗组。观察各组大鼠精神、皮毛、饮食及活动等一般状况；生化法检测血和脑总胆固醇含量；Bielschowsky染色观察海马神经原纤维缠结,HE染色观察大脑皮层及海马淀粉样蛋白沉积及神经元损伤状况；实时荧光定量法检测海马及皮层组织中胆固醇代谢相关基因APOE、CYP46的表达；Western-blot法检测Tau蛋白在ser396位点磷酸化水平。结果：与Ⅰ组相比,Ⅱ、Ⅲ组动物精神萎靡,食欲欠佳,皮毛粗糙,尤以Ⅲ组为甚,Ⅳ组精神好转,食欲增加,皮毛较顺滑。与Ⅰ组比较,Ⅱ组血胆固醇含量无显著差异,Ⅲ组明显高于Ⅱ组(P<0.05)；Ⅳ组含量均低于Ⅱ、Ⅲ组。与Ⅰ组相比Ⅱ、Ⅲ组脑胆固醇含量显著升高,Ⅲ组更为明显；柳茶治疗后Ⅳ组脑胆固醇水平下降,与Ⅲ组相比有显著性差异(P<0.05)。Ⅱ、Ⅲ组大鼠海马及皮层组织可见核深染、固缩,神经元丢失,并出现神经纤维缠结及淀粉样蛋白沉积等典型AD病理形态学变化,其中Ⅲ组大鼠变化更严重。与Ⅱ、Ⅲ组相比,Ⅳ组海马及皮层组织神经元排列相对整齐、紧密,极少见到神经纤维缠结和淀粉样蛋白沉积。与Ⅰ组相比,Ⅱ、Ⅲ组APOE mRNA表达量均增加(P<0.01),且Ⅲ组APOE mRNA表达量高于Ⅱ组(P<0.01),Ⅳ组表达量明显下降至接近Ⅰ组水平(P<0.01)；与Ⅰ组相比,Ⅱ、Ⅲ组CYP46mRNA表达量均减少(P<0.01),而Ⅳ组则明显呈高表达(P<0.01)。与Ⅰ组相比Ⅱ、Ⅲ组磷酸化的Tau蛋白表达量升高,且Ⅲ组更为明显,Ⅳ组磷酸化的Tau蛋白表达量显著下降。结论：高胆固醇血症不仅能够促进淀粉样蛋白沉积形成老年斑,还能通过调节脑内胆固醇代谢关键基因APOE和CYP46的表达加剧Tau蛋白磷酸化形成神经纤维缠结,加重神经元丢失等AD病理学变化。柳茶提取物因有效降低了动物血和脑中胆固醇含量,故使AD大鼠脑组织中神经元丢失、淀粉样蛋白沉积以及神经纤维缠结等病理学变化得以改善,其作用机制可能与调节APOE和CYP46mRNA的表达有关。更多还原

【Abstract】 Objective:To explore the role of Hypercholesterolemia in the outbreak of Alzheimer’s disease (AD) and the treatment effect of liucha extract..Methods:Divide the SD rats into four groups according to Figure Table, namely, normal rates for group Ⅰ, rats with Alzheimer’s disease for group Ⅱ, rates with hypercholesterolemia and Alzheimer’s disease for group Ⅲ, and rates treated with liucha for group Ⅳ. Then the general conditions, including spirit conditions, furs, diets and activities of the rats are observed. Biochemical methods are adopted to detect the blood and brain total cholesterol content; Bielschowsky tainting are used for observation of hippocampal neurons fiber tangles, while HE tainting are for observation of the cerebral cortex and the hippocampus dyeing amyloid deposition and neurons damage condition; Real-time quantitative fluorescence method is to detect the hippocampus and cortex in organization of cholesterol metabolism, CYP46and APOE gene expression; Western-blot method is used to detect Tau protein in ser396site phosphorylation level.Results:Compared with group Ⅰ, group Ⅱ and Ⅲ show signs of sluggishness, poor appetite, fur roughness, which is more severe for group Ⅲ. However, Group Ⅳ is better in spirit and appetite with smooth furs. Compared with normal blood cholesterol content, group Ⅱ had no significant difference, and group Ⅲ was significantly higher than the group Ⅱ (P<0.05); group Ⅳ content are lower than group Ⅱ, Ⅲ. Compared with group Ⅰ, brain cholesterol of group Ⅱ and Ⅲ is significantly increased, with more obvious increasing in group Ⅲ; for rates treated with Liucha, brain cholesterol levels of group Ⅳ dropped, showing significant difference (P<0.05) from group Ⅲ. Rats of group Ⅱ and Ⅲshows signs of hippocampal and cortex tissue visible hyperchromatic nuclei, solid shrinkage, loss of neurons, and the emergence of nerve fibers and tangles amyloid deposition pathological morphology typical AD change, especially for group Ⅲ. Compared with group Ⅱ and Ⅲ, cortical neurons in the hippocampus organization in group Ⅳ are neat, relatively close with rare nerve fiber tangles and amyloid deposition. Compared with group Ⅰ, group Ⅱ, Ⅲ APOE mRNA express quantity increased (P<0.01), and group Ⅲ APOE mRNA express quantity is higher than group Ⅱ (P<0.01), group IV express evidently decreased to the level nearly equivalent with group Ⅰ (P<0.01); Compared with the normal group, both group Ⅱ and Ⅲ have experienced drop of CYP46mRNA express (P<0.01), while group Ⅳ see obviously high expression (P<0.01). Compared with group Ⅰ, the phosphorylated Tau protein expression volume increased for group Ⅱ and Ⅲ, while the increase in group Ⅲ is more apparent. In group Ⅳ, the phosphorylated Tau protein expression has significantly dropped.Conclusion:Hypercholesterolemia can not only promote the amyloid deposition senile plaques form, but also adjust the brain cholesterol metabolism key genes and the expression of the CYP46and APOE, increase Tau protein formed phosphorylation entangled nerve fibers, and worsen neurons lost etc. In conclusion, it speeds up the pathological changes of the AD. The extracts of liucha reduce the cholesterol content in the blood and brain of the animals, thus improve the pathological changes for AD rats, including loss of neurons in the brain tissues, amyloid deposition and nerve fiber tangles. The mechanism has something to do with the content adjustment of the mRNA expression of CYP46and APOE.更多还原