当归芍药散改善痴呆动物脑微血管内皮细胞功能障碍及调节血脑屏障Aβ转运机制的研究

According to recent study, dysfunction of brain vascular endothelial cells may be the common cause of both AD (Alzheimer's Disease) and VD (Vascular Dementia) in the elderly population. Abnormal expression of Amyloid-β receptors which mediate Aβ transport from the brain to the blood may result in Aβ accumulation and aggregation, such as a reduction of LRP-1 expression and an overexpression of RAGE in the brain microvascular endothelial cells (BMEC). So far, there is still no effective medicine to reduce the production of Aβ or prevent it from accumulation. So looking for a new therapy to improve the transport of Aβ becomes popular. The pathogenesis of Chinese medicine for the dementia was considered as "deficiency in origin and excess in superficiality". "Deficiency in origin" means kidney essence deficiency and insufficiency of Qi-Blood, while "Excess in superficiality" means phlegm retention in head and Qi Blood stasis. The Danggui-Shaoyao-San（DSS,the Chinese medicine） has effects on "reinforce insufficiency and reduce excessiveness". Preceding studies indicated its effects on both AD and VD. Our study aims to investigate the effects of DSS and its decomposed recipes on improving the function of BMEC on dementia animal model and the mechanism on Aβ transport across blood brain barrier. To imitate AD and VD animal model, the APP/PS1 transgenic mice and the models of rats caused by ligation of bilateral commoncarotid arteries were used, while cultured BMEC in an oxygen deficit condition was also employed. We hope to provide some new evidences of DSS in treatment with AD and VD.

研究发现，老年人群中痴呆的主要类型AD和VD有着共同的脑血管内皮损伤机制；患者脑微血管内皮细胞膜上介导Aβ转运的LRP-l表达降低及RAGE表达增加，导致血脑屏障Aβ转运机制异常，从而发生Aβ沉积。临床上至今尚无一种能有效抑制Aβ生成和沉积的治疗痴呆方法，而从患者脑中清除Aβ则成为新的研究热点。痴呆的中医病机为本虚标实，本虚为肾精亏损和气血不足，标实为痰浊阻窍和气滞血瘀，目前对AD和VD都有临床疗效的经方当归芍药散则具有补本虚、祛标实特点。本课题从当归芍药散改善痴呆动物脑微血管内皮细胞功能障碍及调节血脑屏障Aβ转运机制入手，用APP/PS1转基因小鼠和结扎大鼠双侧颈总动脉分别模拟AD和VD的病理和学习记忆行为学特征，并用糖氧剥夺的脑微血管内皮细胞作为培养材料，从体内和体外实验两方面探讨当归芍药散及拆方（活血养血药和健脾利湿药）治疗AD和VD的共同作用机制，为其临床应用提供新的实验依据。

本项目从当归芍药散改善痴呆动物脑微血管内皮细胞功能障碍及调节血脑屏障Aβ转运机制入手，用APP/PS1转基因小鼠和结扎大鼠双侧颈总动脉分别模拟阿尔茨海默病（AD）和血管性痴呆（VD）的病理和学习记忆行为学特征，并用糖氧剥夺的脑微血管内皮细胞作为培养材料，从体内和体外实验两方面探讨当归芍药散及拆方（活血养血药和健脾利湿药）治疗AD和VD的共同作用机制。.研究结果主要如下：.①当归芍药散全方及2个拆方均能在一定程度上改善APP/PS1转基因小鼠模型的学习记忆能力、明显减少APP/PS1小鼠脑内的老年斑沉积及降低Aβ1-42的水平。其减少APP/PS1小鼠脑内Aβ1-42的水平可能与其上调血脑屏障上的Aβ转运受体LRP1，下调RAGE有关。②当归芍药散高剂量组及其拆方FBZ（健脾利湿组）均能在一定程度上改善VD大鼠模型的学习记忆能力，但对VD大鼠Aβ转运机制的作用不明显，其神经保护作用机制可能与提高脑中LRP1表达、保护大脑中的神经元细胞以及抑制氧化应激反应有关。③当归芍药散全方含药血清对OGD诱导的内皮细胞损害具有一定保护作用，当归芍药散的拆方DSC（活血养血）水提液对OGD诱导损伤的内皮细胞有保护作用；当归芍药散及两个拆方水提液对Aβ损伤的内皮细胞模型均具有保护作用。.本项目初步揭示当归芍药散治疗AD和VD的共同作用机制（清除脑内的Aβ为主），为其临床应用和和新药开发提供了进一步的实验依据；验证了当归芍药散通过调节血脑屏障Aβ转运机制来提高痴呆模型动物认知功能的假说；通过对当归芍药散药物功效的拆方研究，发现当归芍药散活血养血拆方DCS与健脾利湿拆方FBZ能协同防治AD与VD，但以治痰为重的FBZ药效优于以治瘀为重的DCS，为进一步阐明当归芍药散复方配伍机制提供了的实验依据。