针刺通过AMPK信号通路改善肥胖大鼠瘦素抵抗的机制研究

Since leptin resistance is a remarkable character of diet-induced-obesity in clinical and experimental studies, how to increase leptin sensitivity is a key step in the treatment of obesity. AMPK is the important protein kinase in leptin signal transduction pathways. In the pre-test, we have confirmed that acupuncture could improve leptin resistance and promote AMPK expression in the obese and increase leptin sensitivity. The study is planned about the effects of acupuncture on AMPK signaling pathway (Leptin-leptin receptor-AMPK-ACC-CTP-1) in the liver, skeletal muscle and hypothalamus of rats with diet-induced-obesity. Combined with the modern molecular biotechnology, our works are as follows: (1) Observation of effect of acupuncture on leptin-mediated AMPK signaling pathway of the obese rats. (2) Evaluation of improvement of acupuncture on leptin resistance of the obese rats. We will explore the molecular mechanisms that acupuncture ameliorates leptin resistance and demonstrate the hypothesis that acupuncture would improve leptin resistance through the AMPK signaling pathway, which could enrich acupuncture theory and provide the experimental and theoretical basis for extension of clinical applications of acupuncture on obesity.

在临床和实验研究中发现瘦素抵抗是膳食性肥胖的显著特征，如何提高机体对瘦素的敏感性是解决肥胖症的一个关键步骤。AMPK是瘦素信号通路的一个重要蛋白激酶。我们在前期的试验中已证实了针刺具有改善瘦素抵抗，促进肥胖状态下异常的AMPK的表达，增加瘦素敏感性的作用。本项目拟于在食源性肥胖大鼠（DIO）模型上，研究设计了针刺对肝脏、骨骼肌和下丘脑中瘦素-瘦素受体-AMPK-ACC-CTP-1信号通路的相应指标的效应表现，结合运用现代分子生物研究方法，完成以下研究: （1）观察针刺对肥胖大鼠瘦素介导的AMPK信号通路的影响。（2）评价针刺对肥胖大鼠瘦素抵抗的改善作用。从分子水平阐明针刺改善肥胖瘦素抵抗的机制，论证针刺通过AMPK信号通路改善肥胖大鼠瘦素抵抗的假说。为丰富针灸学理论和推广针刺减肥的临床应用提供实验理论依据。

腺苷酸激活蛋白激酶(AMP-activated protein kinase，AMPK)是一种丝/苏氨酸蛋白激酶，受AMP/ATP比值调控，可准确的开启ATP的分解，关闭ATP的合成，是瘦素信号通路的一个重要靶分子。本研究通过建立食源性肥胖大鼠（DIO）模型，观察电针对肥胖大鼠/小鼠的肝脏、骨骼肌和下丘脑中瘦素-瘦素受体-AMPK-ACC-CTP-1 信号通路的影响，论证电针可通过AMPK 信号通路改善肥胖大鼠瘦素抵抗。结果发现，①电针可以明显降低肥胖大鼠升高的体重、体脂、血脂、瘦素，肝脏中甘油三酯与胆固醇的含量。②电针可以促进肝脏、肌肉、下丘脑中obr、AMPK、CPT-1 mRNA表达，抑制肝脏、肌肉、下丘脑中ACC mRNA表达。③电针可以促进肝脏、肌肉、下丘脑中pAMPKα、pACC蛋白磷酸化水平，激活AMPK信号通路。这些研究结果提示：AMPK信号通路是电针治疗肥胖，改善瘦素抵抗重要的细胞通路之一。电针通过激活AMPK 信号通路，实现改善肥胖大鼠瘦素抵抗与脂质沉积。