基于中枢胰岛素抵抗探讨自噬失调对肾虚阿尔茨海默的影响及机制研究

Deficiency of kidney essence is the key pathogenesis of AD. Modern Chinese medicine research has proved that kidney deficiency is closely related to the dysfunction of autophagy. Based on the abnormal autophagy of neurons, the mechanism and treatment of AD have become the focus of basic and clinical attention. The latest research has found that autophagy is closely related to insulin resistance, and the enhancement of autophagy reduces insulin resistance. Previous studies have confirmed that cell autophagy related gene Atg7 expression decreased in the AD model cell and endothelial, the insulin mediated IRS/PI3K/Akt signal pathway also inhibited, showing insulin resistance, which is an important mechanism of AD pathogenesis. The hypothesis is as follows: when the deficiency of kidney essence is deficient, the neuron's autophagy function is deficient, the expression of Atg7 is reduced, the IRS/PI3K/Akt signal pathway is inhibited, the central insulin resistance is produced, and the development of AD is induced. This study is intended to animal model and cell model as the research object, the IRS/PI3K/Akt signal pathway drived autophagy as a point, to observe the changes of neuronal autophagy deficiency under the condition of AD and its effects on insulin resistance and its mechanism, clarify the key way and molecular mechanism of autophagy, reveal the effect mechanism of tonifying kidney and essence method , and rich scientific connotation of “the Kidney Stores the Essence, Produces the Marrow ”.

肾精亏虚是AD发病的关键病机。现代中医学研究证明，肾虚与细胞自噬功能失调密切相关，基于神经细胞自噬异常探讨AD的机制及治疗已成为基础及临床关注的热点。最新研究发现，自噬失调与胰岛素抵抗关系密切，增强自噬可减轻胰岛素抵抗。课题组前期研究证实在AD模型细胞及血管内皮细胞自噬相关基因Atg7表达降低时，胰岛素介导的IRS/PI3K/Akt信号通路也出现了抑制，出现胰岛素抵抗，后者是AD发病的重要机制。由此提出如下假说：肾精亏虚时，神经元的自噬功能缺陷，Atg7表达降低，抑制IRS/PI3K/Akt信号通路，发生中枢胰岛素抵抗，导致AD的发生发展。本研究拟以小鼠模型及细胞模型为研究对象，以自噬驱动的IRS/PI3K/Akt信号通路为切入点，观察肾虚AD状态下神经元自噬的改变及其对胰岛素抵抗的影响及机制，阐明自噬影响AD的关键途径、环节及分子，揭示补肾填精法的效应机制，丰富“肾藏精生髓”的科学内涵。

阿尔茨海默病是最常见且发病率最高的痴呆类型，属于中医学“呆病”“健忘”等范畴，临床上表现为记忆减退、失语、失认、抽象思维和计算力损害等，严重影响日常生活能力。脑髓是神志活动的物质基础。肾藏精，精生髓，脑为髓海，肾精不足，髓海空虚，神思障碍，遂生痴呆。因此，肾精亏虚，髓海不足是AD发病的关键病机。现代中医学研究证明，肾虚与细胞自噬功能失调密切相关，正常的自噬功能是气化功能的微观体现。最新研究发现，自噬失调与胰岛素抵抗关系密切，增强自噬可减轻胰岛素抵抗。为了探讨AD的部分发病机制及补肾填精法的治疗机制，本研究在中医理论的指导下，基于中枢胰岛素抵抗揭示自噬异常对肾虚AD状态下神经细胞的影响及机制。. 本研究在小鼠侧脑室注射Aβ1-42建立小鼠AD模型，并利用皮下注射氢化可的松建立肾虚AD模型，以Aβ刺激SH-SY5Y细胞建立细胞模型，应用补肾填精中药六味地黄丸进行干预，通过形态学观察、分子生物学等技术，从整体和细胞两个层次，探讨自噬异常对神经细胞的影响及机制，以及补肾填精法的部分治疗机制。结果表明，自噬相关基因Atg7对SHSY-5Y细胞胰岛素依赖的IRβ/PI3K/AKT信号通路的具有显著的正向调节作用，AD状态下，神经细胞自噬相关基因表达下降，胰岛素信号通路出现障碍。补肾填精法可以显著促进AD状态下神经细胞的自噬，改善胰岛素抵抗，进而增强动物的识记能力，改善海马组织及SH-SY5Y细胞的形态结构。本项目有助于为中医“从肾论治”AD及相关神经退行性疾病提供科学依据，丰富“肾藏精，生髓”的理论科学内涵，同时为挖掘以自噬为有效靶点防治神经退行性疾病的补肾中药提供新的研究策略和实验依据。