基于肠道菌群及SCFAs/FFAR/肠促胰岛素信号轴探索清胃降浊中药调节糖脂代谢紊乱的机制研究

JiangTangTiaoZhi Formula (JTTZF) has been proved in lowering blood glucose, regulating lipids, reducing weight and improving insulin resistance in clinical practice and large-scale clinical trials. Previous study had showed that the mechanism of JTTZF is related to regulating gut microbiota, while the details of action remain to be explored. Researches have confirmed that gut microbiota could regulate glycolipid metabolism by incretin. And the incretin secretion is affected by short-chain fatty acids (SCFAs) and their receptors - free fatty acid receptors (FFAR). So the scientific hypothesis of this project is put forward: the imbalance of gut microbiota is the important pathogenesis of metabolic disorders, SCFAs/FFAR/incretin is the key signal axis for transmission, JTTZF could improve the metabolic disorders by regulating the signal axis of SCFAs/FFAR/incretin via gut microbiota. In this project, C57BL/6J model mice would be used to confirm the efficacy of JTTZF on glycolipid metabolism and gut microbiota, and to further reveal the mechanism of JTTZF is through regulating gut microbiota, SCFAs and their downstream receptors in two-way by fecal microbiota transplantation technology, in order to provide objective basis for regulating gut microbiota and improving metabolic disorders.

降糖调脂方经多年临床实践及前期大型临床研究证实，该药具有降糖、调脂、减轻体重、改善胰岛素抵抗的作用，其疗效机制与调节肠道微生态相关，但具体作用途径及靶点仍待阐释。现有研究证实，肠道菌群可通过短链脂肪酸(SCFAs)及其受体游离脂肪酸受体(FFAR)影响肠促胰岛素分泌，从而调节糖脂代谢。综上提出科学假说：肠道菌群失衡是糖脂代谢紊乱的重要发病机制，SCFAs/FFAR/肠促胰岛素是关键信号传导通路；降糖调脂方可基于肠道菌群调节SCFAs/FFAR/肠促胰岛素信号轴，发挥清胃降浊、改善糖脂代谢紊乱功效。本项目拟采用C57BL/6J模型小鼠验证降糖调脂方对糖脂代谢及肠道微生态的影响，进一步利用粪菌移植技术双向阐明降糖调脂方通过调控肠道菌群、SCFAs及其下游受体发挥糖脂同调的疗效机制，旨在为清胃降浊中药调节肠道微生态改善代谢紊乱提供科学依据。

本研究旨在探讨降糖调脂方(JTTZF)通过调节肠道微生态改善糖脂代谢紊乱的作用机制。采用HFD诱导C57BL/6J小鼠构建糖脂代谢紊乱模型，随机分为正常组、模型组、JTTZF高中低剂量组，结果显示JTTZF干预后显著改善小鼠FPG、OGTT及胰岛素抵抗状态，以高与中剂量组改善程度更显著；显著改善小鼠TC水平(p<0.01)，以中剂量组改善程度最显著。在组织病理学方面，模型组小鼠组织可见腺泡细胞与胞质空泡、上皮细胞脱落、结缔组织增生等病理改变，经干预后明显改善。肠道微生物组高通量测序分析提示，JTTZF干预后增加Bacteroidetes和Proteobacteria丰度，降低Firmicutes和Verrucomicrobia丰度；Bacteroides,Akkermansia,Odoribacter表达含量显著升高。相关分析提示TG与在JTTZF和正常组富含Odoribacter呈负相关，TC、葡萄糖和体重与Lactobacillus呈负相关，Parabacteroides与血糖血脂呈正相关。降糖调脂方可通过影响Akkermansia和Odoribacter表达发挥改善糖脂代谢紊乱作用。进一步结合KEGG与EggNOG数据库进行基因功能注释，表明JTTZF干预后缓解的代谢途径包括氨基酸、能量、碳水化合物、脂质和核苷酸的代谢、聚糖生物合成和代谢、信号转导等。研究通过粪菌移植验证JTTZF通过调节肠道菌群改善糖脂代谢，结果证实接受JTTZF干预的粪菌移植小鼠体重和血糖降低更显著，并改善模型小鼠的胰岛素抵抗状态；肠道菌群测序分析提示JTTZF干预后Bacteroides,Helicobacter,Akkermansia与Odoribacter表达丰度增加，而Parabacteroides经干预后表达降低，与前期测序分析结果一致。同时JTTZF可改善粪便Butyrate表达含量，促进SCFAs生成；JTTZF可调控血清及组织中FFAR及肠促胰岛素表达，下调血清FFAR2、FFAR3表达，上调血清GLP-1、GIP表达；调控回肠组织中FFAR与肠促胰岛素的表达，提示JTTZF基于肠道菌群调节Butyrate为代表的SCFAs代谢物表达，进一步调控FFAR及肠促胰岛素发挥改善糖脂代谢紊乱作用，研究为中医药通过肠道微生态影响宿主糖脂代谢提供科学证据。