以“肠道菌-胆汁酸-脑”对话关系为核心探讨滋补脾阴法防治糖尿病认知功能障碍的生物学机制

The therapeutic effect of nourishing Spleen-Yin method on diabetes-associated cognitive decline (DACD) is remarkable. Base on the nourishing Yin and invigorating spleen, eliminating phlegm and removing blood stasis characteristics of ZiBuPiYin recipe (ZBPYR) and according to our previous research and advanced information, we propose a hypothesis that ZBPYR could reduce the level of cytotoxic bile acid in blood and brain tissue, alleviate neuron cell damage and improve the symptoms of DACD by regulating the gut microbiota and bile acid metabolism disorder. The metabolic profiles of bile acids in DACD mice were constructed by high-throughput target metabolomics technology and the gut microbiota feature of DACD mice was evaluated by metagenomics. The data model of “gut microbiota-bile acid metabolism-pharmacodynamics” was constructed by multivariate statistical analysis to reveal the internal relationship of gut microbiota, bile acid and brain and the biological mechanism was validated by molecular biology technology. According to the strategy, we could discover and clarify the new biological mechanism of ZBPYR in preventing and treating DACD, and provide a theoretical basis for more suitable clinical utilization of traditional Chinese medicine for the prevention and treatment of DACD in clinic.

滋补脾阴法防治糖尿病认知功能障碍（Diabetes-Associated Cognitive Decline, DACD）临床疗效显著。申请人结合前期相关研究积累及有关前沿信息，立足于滋补脾阴法“滋阴补脾，祛痰化瘀”的防治特点，提出假说：滋补脾阴方药通过调控肠道菌群结构及胆汁酸代谢紊乱，降低血液及脑组织中具有细胞毒性的胆汁酸水平，减轻神经元细胞损伤，改善DACD。本项目拟在药效学评价的基础上，运用高通量靶标代谢组学技术构建DACD小鼠胆汁酸代谢轮廓，采用宏基因组学技术建立DACD小鼠肠道菌谱。运用多元统计分析方法构建“肠道菌-胆汁酸代谢-药效”相关性数据模型来揭示“肠道菌-胆汁酸-脑”之间的内在联系，并利用现代分子生物学技术进行机制验证，以此来发现和阐明滋补脾阴法防治DACD新的生物学机制，为临床制定更为契合的中医药防治DACD的方案提供理论依据。

本研究基于滋补脾阴法对于糖尿病认知功能障碍有确切临床疗效的基础上，认为糖尿病认知功能障碍的核心病机为“脾气阴虚，痰瘀蒙阻清窍”。结合前期对糖尿病认知功能障碍患者的非靶标代谢组学的宏观分析结果以及相关领域的前沿研究报道，将研究聚焦在糖尿病认知功能障碍患者胆汁酸代谢的微观调控上。我们认为糖尿病引起了肠道菌群结构和胆汁酸代谢轮廓的改变，某些异常改变的胆汁酸分子作为传导信号影响了中枢神经系统，导致认知功能障碍。基于此假说，提出从“肠道菌-胆汁酸-脑”对话关系出发探讨滋补脾阴法防治糖尿病认知功能障碍生物学机制的研究思路。项目通过体内外相关实验，得出以下结论：糖尿病认知功能障碍小鼠体内肠道菌群结构失调，某些参与胆汁酸代谢的肠道菌如狄氏副拟杆菌、梭菌梭状芽胞杆菌等丰度升高，导致体内胆汁酸代谢异常。异常改变的LCA、TDCA、GDCA、CDCA等具有神经毒性的胆汁酸等使肠道与脑组织的胆汁酸转运体ASBT活性升高，致使胆汁酸重吸收增加，导致脑内毒性胆汁酸含量升高，于此同时，脑组织内具有神经保护作用的胆汁酸如UDCA、TUDCA等含量降低，使神经元细胞失去保护，神经元发生损伤，导致认知功能障碍的发生。滋补脾阴方药具有较好的控制血糖、改善胰岛素抵抗的作用，并且对糖尿病认知功能障碍小鼠的神经元损伤具有保护和修复作用，能够提升糖尿病认知功能障碍小鼠的学习记忆能力，改善小鼠的认知功能。其防治糖尿病认知功能障碍的潜在生物学机制为：滋补脾阴方药能够调控糖尿病认知功能障碍小鼠肠道菌群结构，改变胆汁酸的代谢与重吸收，降低脑内神经毒性胆汁酸的水平，提升脑内具有神经保护作用的胆汁酸水平，改善神经元损伤，从而提升学习记忆能力，改善认知功能障碍。