针刺通过SIRT1调控肠道微生物群—肠—脑轴改善胰岛素抵抗肥胖的机制研究

The role of gut microbiota in the energy balance of obesity is more and more concerned. The changes of gut microbiota induce impairments in intestinal immune homeostasis and the mucosal barrier with increased activation of the inflammatory pathways, which are closely related with the development of insulin resistance (IR). Previous studies have found that acupuncture can activate skeletal muscle and hypothalamic SIRT1, and reduce serum and hypothalamic inflammatory factor expression, leading to improvement of insulin resistance and energy metabolism of obesity, but the central SIRT1 inhibitor can not completely block the effect of acupuncture. The aim of this study is to establish the insulin resistance obese rat model, intervened by electro-acupuncture. The changes of SIRT1-mediated anti-inflammatory pathways and their downstream proinflammatory genes will be observed. The metagenome technique is used to detect the structure and function of gut microbiota based on high-throughput sequencing. The differences of genes and their metabolic functions will be analyzed. The gastrointestinal motility, barrier function and secretion function are tested to evaluate the effects of acupoints on the gastrointestinal dysfunction. SIRT1 inhibitor is applied to investigate the mechanism of acupuncture in regulating the gut microbiota-gut-brain axis through SIRT1 activation, thereby improving the energy balance disorders and insulin sensitivity. Moreover, microbiota after acupuncture intervention will be transplanted into the IR obesity rats to evaluate the potential effect and value. This study will provide effective theoretical and experimental basis for the clinical use of acupuncture to prevent obesity.

肠道微生物群在肥胖能量平衡中发挥的作用越来越受关注，其变化导致肠免疫内稳态失常及炎症活化导致的肠粘膜障碍与胰岛素抵抗（IR）的发展密切相关。前期研究发现针刺可激活骨骼肌和下丘脑SIRT1，并降低炎症因子表达，改善肥胖IR和能量代谢，但中枢SIRT1抑制剂并不能完全阻断针刺的效应。本项目拟以电针干预IR肥胖大鼠模型，观察肠道SIRT1介导的抗炎通路分子及其下游促炎基因的转录和表达变化，运用基于高通量测序的宏基因组技术检测肠微生物群结构和功能变化，分析差异基因及其代谢功能；以胃肠动力、屏障功能和分泌功能评价针刺对肥胖所致的胃肠功能紊乱的影响；运用SIRT1特异性抑制剂，阐释针刺可能通过SIRT1调控肠道微生物群—肠—脑轴，从而改善能量平衡和胰岛素敏感性的机制；拟用菌群移植技术，将针刺干预后的菌群移植到大鼠肠道，探讨针刺后肠道微生物群的潜在应用价值。本研究将为临床运用针刺防治肥胖提供实验依据。

肠道微生物群在肥胖能量平衡中发挥的作用越来越受关注，其变化导致肠免疫内稳态失常及炎症活化导致的肠粘膜障碍与胰岛素抵抗（IR）的发展密切相关。前期研究发现针刺可激活骨骼肌和下丘脑SIRT1，并降低炎症因子表达，改善肥胖IR和能量代谢，但中枢SIRT1抑制剂并不能完全阻断针刺的效应。在此基础上，本项目提出“标本配穴”针刺可以通过肠道微生物群-肠-脑轴调节肥胖IR模型肠道微生物群结构和功能、炎症状态和胃肠功能，针刺改善能量代谢和胰岛素敏感性的机制可能与肠道SIRT1介导的抗炎通路的调控参与有关，且针刺干预后的肠道微生物群移植可能改善肥胖IR大鼠的能量代谢与胰岛素敏感性。围绕这一假说，本研究以高脂饲料诱导的大鼠作为肥胖胰岛素抵抗模型，观察到“标本配穴”针刺对肥胖IR大鼠糖脂代谢和胰岛素敏感性的整体调节作用，电针与SIRT1激动剂一样，能够降低血清总胆固醇、甘油三酯和游离脂肪酸的水平，提高大鼠胰岛素敏感性，且这一作用能被SIRT1抑制剂部分阻断；电针与SIRT1激动剂能够降低肥胖IR大鼠胃与小肠肌电振幅和频率，纠正胃肠动力紊乱，且该作用能被SIRT1特异性抑制剂阻断；电针介导的SIRT1激活可上调IR肥胖大鼠小肠组织SIRT1蛋白及基因的表达水平，从而下调TLR4蛋白和基因的表达，降低NF-κB乙酰化作用，降低其转录活性，从而下调NF-κB下游的炎症因子基因表达，最终达到抗炎的作用；电针能够提高脑肠肽中枢敏感性并改善肥胖IR大鼠肠道微生物群结构及功能，且这一良性效应能够通过肠道微生物群移植继续得到发挥；针刺干预后的肠道微生物群移植能够改善肥胖IR大鼠能量代谢与胰岛素敏感性，并通过修复肠道屏障功能改善肠道内环境稳态。本研究将为临床运用针灸腧穴配伍防治肥胖胰岛素抵抗及相关疾病提供实验依据。