慢性心衰导致AD发病中Aβ代谢异常的机制及芪苈强心胶囊的干预研究

As "cardiogenic dementia" is proposed, more attention has been paid to the field of disciplines which links heart and brain. Alzheimer's disease, which is represented by the β-amyloid deposits in the brain, has been proved closely related with chronic heart failure. Though ACEI have a positive effect on the patients suffering from chronic heart failure with cognitive impairments and Alzheimer's disease, but to our knowledge, no investigations have explored the relationships between AngII, blood brain barrier and β-amyloid based on heart failure. In our present study, we have established heart failure with cognitive impairment rat model and proved the dysfunction of blood brain barrier. In this study, starting from the theory of Aβ sourcing from blood and in the core of BBB, we will establish heart failure after MI rat model,and brain microvascular endothelial cell and astrocytes will be isolated and purified respectively in vitro BBB model. We will use transmission electron microscope,flow cytometry, immunofluorescent double staining method and molecular biology method to observe the tight junction of BBB, the activation of ROS and the expression of Aβ transport protein. Based on this, we sought to explain that AngII induces oxidative stress and disorders of energy metabolism, which leads to BBB injured and abnormality of Aβ transport protein and results in an increase of Aβ in the brain. At the same time, the study will try to explore the effect of reducing intracerebral Aβ of QiliQiangxin capsule via Boosting Qi and Yang Warming, Promoting Blood Circulation and Draining Collateral Method, providing the theoretical basis for the treatment of heart and brain under the guidance of disease theory.

随着“心源性痴呆”的提出，人们更多关注心脏和大脑相互关联的学科领域。以β-淀粉样蛋白（Aβ）脑内沉积为标志的阿尔茨海默病（AD）被证实与慢性心衰密切相关，虽然ACEI治疗心衰后认知障碍或AD患者有较好效果，但心衰背景下AngII、血脑屏障（BBB）、Aβ之间的关系还不清楚。我们前期实验成功复制出心衰后认知障碍大鼠，并证实其BBB屏障功能受损。本研究从Aβ血源学说出发，以BBB为核心，采用心梗后心衰大鼠模型、脑微血管内皮细胞和星形胶质细胞共培养BBB体外模型，运用电镜、流式细胞仪、免疫双标及分子生物学等方法，观察ROS的激活、BBB紧密连接和Aβ转运蛋白表达等，以阐明AngII诱导氧化应激和能量代谢障碍，导致BBB破坏和Aβ转运异常，引起脑内Aβ增加的机制；同时，探索芪苈强心胶囊通过益气温阳，活血通络稳定BBB微环境，减少脑内Aβ的疗效机制，为在病络理论指导下的心脑同治提供理论依据。

阿尔兹海默病（AD）与慢性心衰密切相关，但心衰背景下AngII、血脑屏障（BBB）、Aβ之间的关系还不清楚。本研究成功复制出心衰后认知障碍大鼠，以脑微血管内皮细胞建立BBB体外模型，分别从体内和体外探讨AngII诱导氧化应激和能量代谢障碍，导致BBB破坏和Aβ转运异常，引起脑内Aβ增加的机制；深入探讨经AngII触发ROS--ERK1/2-NF-κB信号通路激活与Aβ相关转运蛋白表达之间的相互关系。并以芪苈强心胶囊进行干预，观察药物对BBB转运Aβ的影响及可能的作用机制。. 结果显示心衰后认知障碍大鼠血浆及海马组织中Ang II显著升高（P＜0.01），海马组织Aβ42 浓度显著升高（P＜0.05），芪苈强心胶囊能够显著降低血浆中Ang II（P＜0.01）、海马组织中Ang II（P＜0.05）及海马组织中Aβ42 浓度（P＜0.05）；此外，芪苈强心能够显著减少模型大鼠海马区ROS水平，保护AD大鼠海马区神经细胞形态结构的完整性；模型大鼠海马区，AT1R蛋白表达量显著增加（P＜0.01），转运蛋白LRP1表达减少（P＜0.05），连接蛋白Occludin和claudin-5显著减少（P＜0.01），芪苈强心能够抑制AT1R蛋白表达（P＜0.05），促进连接蛋白Occludin（P＜0.01）和claudin-5（P＜0.05）表达；RT-PCR发现芪苈强心胶囊能够降低Mapk1、Mapk3及Nfkb1基因转录水平。采用培养小鼠脑微血管内皮细胞bEnd3，成功建立了体外BBB模型。芪苈强心胶囊可以减少AngII刺激小鼠脑微血管内皮细胞后增多的ROS，保护线粒体结构，调控细胞功能，提高细胞生存率。. 通过本研究结果证实，慢性心衰认知功能障碍大鼠脑内Aβ水平增加与BBB屏障功能受损及Aβ受体转运蛋白表达失衡有关。芪苈强心胶囊能够保持BBB的结构的完整性，抑制Aβ的透过，这主要与抑制AngII诱导BBB氧化应激及能量代谢障碍有关，其中是否通过影响ROS--ERK1/2--NF-κB信号参与调控还需进一步确认。本研究结果为病络理论指导下慢性心衰AD的中医药防治提供科学依据。