从益肾化浊法调控“Aβ自聚集毒性”效应链反应探讨老年性痴呆防治中“治未病”思想的现代生物学机制

Alzheimer’s disease (AD) is a common neurodegenerative disease, and its main pathogenesis is excessive formation and accumulation of Aβ toxicity leading to the loss of neurons in the brain. Previous studies have proved that tonifying kidney Chinese herbs can delay the progress of AD by the regulation of Aβtoxicity to promote the differentiation of neural stem cells for the supply of neuronal loss. Since AD is incurable, under the guidance of “prevention before the disease attack” in the preventive treatment theory in traditional Chinese medicine (TCM) combined with the correlation between the pathological changes of “Kidney deficiency- turbidity toxin-brain collaterals lesion” in TCM of AD and the process of Aβ accumulation to toxicity, this study focuses on the stage preceding the AD attack, targets at Aβself-assembly before its neurotoxicity, uses 3-month SAMP mice and primary neurons of SD fetal rats as the research object for the observation of curative effect in vivo and the mechanism in vitro by behavior, morphology and molecular biology to observe the effect of Yishen Huazhuo Method Chinese medicine on the learning and memory ability of mice, the morphology and amount of neurons and key protein and gene expression in the formation, assemblage and deposition of Aβmonomer, thus to preliminarily clarify the possible mechanism of this method for delaying and even preventing the occurrence of AD via the regulation of Aβself-assembly to toxicity, which will provide some experimental evidence for the explanation of modern biological basis to prevent and treat AD by TCM under the guidance of preventive treatment theory in TCM.

阿尔茨海默病（AD）是常见的中枢神经退行性疾病，脑内Aβ过量生成、聚集成毒导致神经元缺失是其主要发病机制。前期研究证实补肾中药可通过调控Aβ毒性干预后神经干细胞的分化补充神经元的缺失，从而延缓AD的进展。然而基于该病的不可治愈性，在中医治未病思想“未病先防”理论内涵的指导下，结合痴呆“肾虚-浊毒-病损脑络”的病机演变与Aβ聚集成毒过程的相关性，本项目着眼于AD发病前，以Aβ产生神经毒性前的自聚集效应为切入点，采用3月龄SAMP8小鼠和SD胎鼠神经元为研究对象，从体内疗效观察到体外机制研究逐步深入，借助行为学、形态学及分子生物学检测方法观察益肾化浊法中药对小鼠学习记忆能力、神经元形态数量及Aβ单体生成、聚集、沉积过程中关键蛋白和基因表达的影响，初步明晰该法通过调控Aβ自聚集毒性效应从而延缓乃至预防AD发生的可能作用机制，为阐释中医治未病思想指导该法防治AD的现代生物学基础提供部分实验依据。

阿尔茨海默病（AD）是常见的中枢神经退行性疾病，脑内Aβ过量生成、聚集成毒导致神经元缺失是其主要发病机制。前期研究证实补肾中药可通过调控Aβ毒性干预后神经干细胞的分化补充神经元的缺失，从而延缓AD的进展。然而基于该病的不可治愈性，在中医治未病思想“未病先防”理论内涵的指导下，结合痴呆“肾虚-浊毒-病损脑络”的病机演变与Aβ聚集成毒过程的相关性，本项目着眼于AD发病前，以Aβ产生神经毒性前的自聚集效应为切入点，采用3月龄SAMP8小鼠和SD大鼠原代神经元为研究对象。通过Morris水迷宫检测小鼠在益肾化浊法中药干预前后学习记忆能力的变化；通过尼氏染色和电镜观察该法对小鼠大脑海马区神经元数量及超微结构的影响；通过Elisa、免疫组化及Western blot观察该法对小鼠大脑海马区Aβ代谢过程中不同病理产物的影响。.通过以上研究工作得出以下结论：益肾化浊方可有效改善SAMP8小鼠早期学习记忆能力减退，延缓AD疾病进程，该作用与保护神经元形态结构、减轻神经元缺失及提高突触传递功能有关；益肾化浊方可减轻SAMP8小鼠海马神经元和突触功能缺损的可能机制在于通过调控Aβ自聚集毒性效应，下调BACE1的表达、促进APP逆转运，以减少Aβ生成，并抑制Aβ“自聚集”产生神经毒性，从而起到神经保护、防治AD的作用；同时益肾化浊方在体外也证实能有效减少神经元内Aβ的生成，提高细胞活力，发挥神经保护作用，与BACE1抑制剂相似，对于AD的防治具有一定作用，该结论充分验证了本项目的科学假说。.该项目初步明晰了益肾化浊法通过调控Aβ自聚集毒性效应从而延缓乃至预防AD发生的可能作用机制，为阐释中医治未病思想指导该法防治AD的现代生物学基础提供部分实验依据。