肉苁蓉总苷改善阿尔兹海默病学习认知功能障碍的机制及信号通路研究

Alzheimer's disease (AD) is closely related to autophagy, autophagy dysfunction can lead to scavenge disorders of Aβ and Tau protein, then caused cognitive dysfunction, so autophagy is considered to be a treatment target for cognitive dysfunction of AD. Our previous study demonstrated that Glycosides of cistanche (GCs) can inhibit the deposition of Aβ, improve cognitive function of AD and synaptic plasticity, as well as have an androgen-like pharmacodynamic effect, while the exact pharmacodynamic mechanism of GCs still needs to further study. Whether GCs improve cognitive dysfunction of AD via autophagy and related signaling pathway, as well as mediate by the specific androgen receptor (AR) has not been reported at home and abroad. In this subject, senescence accelerated mice prone 8 (SAMP8) were used as the AD model animals, primary hippocampal neurons incubated by soluble Aβ1-42 oligomers as the AD model cells, animals and cells were administered GCs, agonist or inhibitor of AMPK/mTOR autophagic signaling pathway and androgen receptor antagonist (flutamide). Research on autophagic signaling pathway will be conducted by using experimental techniques of behavior, morphology, neuroelectrophysiology and molecular biology, to explore the molecular mechanism and signaling pathway of GCs improving cognitive dysfunction of AD, to provide theoretical and experimental basis for research and development of Herha Cistanches and targeted therapy for AD.

阿尔兹海默病（AD）与自噬密切相关，自噬功能紊乱可导致Aβ与Tau蛋白清除障碍，进而引起学习认知功能障碍，故自噬被认为是治疗AD学习认知功能障碍的作用靶点。我们的前期研究证明肉苁蓉总苷（GCs）能抑制Aβ的沉积，改善AD学习认知功能及突触可塑性，且具有类雄激素样药效作用，但其确切的药效机制尚需深入研究。GCs是否通过自噬及相关信号通路改善AD学习认知功能障碍，该过程是否依赖特异性雄激素受体（AR）介导，国内外未见报道。本课题采用SAMP8小鼠为AD动物模型，原代海马神经元Aβ1-42寡聚体孵育制备AD细胞模型，模型动物及细胞给予GCs、AMPK/mTOR自噬通路诱导剂、抑制剂及AR拮抗剂（氟他胺）干预。采用行为学、形态学、神经电生理及分子生物学等技术，围绕自噬调控信号通路展开研究，探讨GCs改善AD学习认知功能障碍的分子机制及信号通路，为GCs靶向治疗AD及肉苁蓉的研发提供理论及实验依据。

既往证明，自噬功能紊乱导致Aβ与Tau蛋白清除障碍，进而引起阿尔兹海默病（AD）学习认知功能障碍，故自噬被认为是治疗AD学习认知功能障碍的作用靶点。本课题采用了SAMP8小鼠为AD动物模型，原代海马神经元Aβ1-42寡聚体孵育制备AD细胞模型，通过量效实验和时效实验确定了肉苁蓉总苷（GCs）的最佳给药剂量（在体实验和体外实验），并在此基础上模型动物及细胞给予GCs、AMPK/mTOR自噬通路抑制剂（自噬抑制剂：3-Ma、AMPK抑制剂：Compound C）及AR拮抗剂（氟他胺）进行干预。采用Morris行为学分析系统评价动物学习认知功能，尼氏染色观察了大脑皮层及海马区锥体细胞的形态，高尔基染色及透射电镜等形态学方法检测了突触形态可塑性的变化，分子生物学技术检测突触相关标志物、AMPK/mTOR自噬通路相关标志物表达量的变化，评价GCs对突触及自噬功能的影响。我们的研究结果证明，GCs能有效抑制Aβ的沉积，改善AD学习认知功能及突触可塑性。此外，GCs可以显著提高动物血清睾酮含量，且与给药剂量呈正相关，具有类雄激素样药效作用。实验结果表明，GCs可显著改善AD模型动物突触可塑性，其可能的机制为GCs通过调控AMPK/mTOR信号通路抑制机体过渡自噬，进而改善AD学习认知功能障碍。此外，GCs通过特异性介导AR改善AD模型动物突触可塑性和认知功能障碍。该实验结果的取得，将为GCs靶向治疗AD及肉苁蓉的研发提供理论及实验依据。