基于冰片可逆开放血脑屏障对MSCs-NGF抗阿尔茨海默病的作用机制研究

Senile Dementia is a neurodegenerative disease, posing a serious threat to public health in the older people. Among Senile Dementia, the incidence of Alzheimer's disease (AD) is the highest. AD is mainly characterized by brain pathological damage and severe cognitive impairment. Mesenchymal stem cells (MSCs) is a kind of adult stem cells which can be induced into neuron-like cells to promote repairment of damaged brain. Nerve growth factor (NGF) is a neurotrophic factor which plays an important role in the growth and development of neurons and neurotransmitter synthesis, also plays a strong role in brain protection together with MSCs. We hypothesize that MSCs, transfected with heterozygous AAV2/1 vector containing NGF gene construct and implanted in AD brains, would be a positive and effective measures to prevent the development of AD. The project intends to use borneol’s reversible open nature of blood brain barrier to promote MCSs-NGF implanted intransvenously into the AD brain based on the preliminary. Obtain MCSs-NGF biological informations of anti-AD by detecting the brain tissue morphology、changing of TrkA/Ras pathway related molecules and learning and memory function. Combine with cultured brain slices experiments to explore the effects of MCSs-NGF on hippocampal neuronal survival and differentiation, and to explore MCSs-NGF’s intervention and specific mechanisms, and to provide new ideas for effective treatment strategy of AD.

老年痴呆症是一种严重危害老年群体健康的神经退行性疾病，其中以阿尔茨海默病(AD)发病占首位，AD主要特征为脑病理损害和严重认知障碍。骨髓间质干细胞(MSCs) 是一种成体干细胞，可被诱导为神经元样细胞促进受损脑的修复。神经生长因子(NGF)是神经元发育生长、递质合成的重要营养因子，与MSCs共同发挥强大的脑保护作用。我们推测构建载有NGF基因的杂合型AAV2/1载体转染MSCs植入AD模型鼠脑内,将是阻止AD发生发展的积极有效措施。本项目在前期基础上采用早中期AD鼠经静脉植入MCSs-NGF，并以冰片可逆开放血脑屏障，促使MCSs-NGF进入AD脑内。通过脑组织形态结构与TrkA/Ras通路等相关分子改变和认知功能变化，获取MCSs-NGF抗AD的生物学信息。结合培养的脑片实验，探讨干预对脑内神经元存活与分化的影响，阐明MCSs-NGF作用及具体机制，为临床有效治疗AD的策略提供新思路。

阿尔茨海默病（Alzheimer's disease，AD）是一种进行性发展的神经退行性疾病，占老年痴呆症发病率的50%～75%，生存期一般为5～10年，严重危害老年人的身心健康。目前国内外学者普遍倾向于Aβ毒性学说，因此清除脑内异常增多聚集的Aβ成为治疗AD的一种有效方法。但目前清除Aβ的策略仍具有血脑屏障通过率低、靶向性差、副作用强等弊端。骨髓间质干细胞(MSCs) 是一种成体干细胞，可被诱导为神经元样细胞促进受损脑的修复。神经生长因子(NGF)是神经元发育生长、递质合成的重要营养因子，与MSCs共同发挥强大的脑保护作用。前期我们构建了载有NGF基因的杂合型腺相关病毒（AAV2/1）载体，转染MSCs并使其高表达NGF，通过尾静脉注射MCSs-NGF到早中期AD鼠，同时利用中药冰片可逆开放血脑屏障，促使MCSs-NGF进入AD脑内。AAV2/1可以高效转染MSCs，并呈现明显高表达。冰片开放血脑屏障具有可逆性和时效性，在灌胃后1-2h开放血脑屏障最佳。与未应用冰片组相比，冰片明显促进了MCSs-NGF在脑内的定植。经应用冰片和MCSs-NGF后，AD鼠的行为学指标表明认知功能得到明显改善。通过高通量测序技术，获取了MCSs-NGF抗AD的生物学信息。通过脑组织形态结构与相关信号通路分子的检测发现，高表达的NGF通过TrkA/Ras信号通路的改变，促进了脑内神经元存活与分化，这也为临床有效治疗AD的策略提供新思路。