人参皂苷Rg1调控胰岛素抵抗肝脏葡萄糖输出的分子机制研究

Insulin resistance plays an important role in the occurrence and development of type 2 diabetes and its complications. Insulin resistance is a notable feature and pathological basis in type 2 diabetes. Liver, fat and skeletal muscles are the major tissues/organs responsible for the development of insulin resistance. Previous studies have suggested that Ginsenoside Rg1 , one of the major Ginsenosides found in Panax pseudoginseng and ginseng, is the important active ingredient that can inhibit inflammatory response and oxidative stress. It can also inhibit the phosphatidylinositol-3 kinase /Akt (PI3K/Akt) signal pathway in the adipose tissue and skeletal muscle and promote glucose uptake, reducing consequently insulin resistance and achieve hypoglycemic pharmacological effects. However, it is not clear whether the Ginsenoside Rg1 affects glucose metabolism in the liver by inhibiting inflammatory response and oxidative stress. In the proposed study we seek to utilize both animal and cultured cell models to determine the role and molecular mechanism of action of Ginsenoside Rgl in insulin resistance by detecting the contents of inflammation and oxidative stress- associated factors in response to stimulation with different concentrations of Ginsenoside Rg1 for different periods of time. Meanwhile, we will investigate the changes in the expression levels of NADPH oxidase3 (NOX3), nuclear factor-κB (NF-κB) and the relevant factors in the p38 mitogen-activated protein kinase (MAPK) and c-Jun Nterminal kinase (JNK) signal pathways, which affect glucose output from hepatocytes. Moreover, experiments will be also carried out to examine the alterations in key regulatory factors of Akt such as tribbles3. The ultimate goal of this study is to elucidate whether Ginsenoside Rg1 decreases glucose output from liver by suppressing inflammatory response and oxidative stress, thus preventing insulin resistance. The fundamental objective of our study is to seek a novel and effective treatment for the life-threatening diabetes. Our proposed study will promote the development and utilization of Panax pseudoginseng and its extracts in Yunnan.

胰岛素抵抗（IR）在2型糖尿病及其并发症的发生和发展中起着重要作用，是2型糖尿病的显著特点和病理学基础。肝脏、脂肪和骨骼肌是引起IR的主要组织器官。研究表明，三七和人参中重要的活性成分人参皂苷Rg1（Rg1）可抑制炎症反应和氧化应激；Rg1也可通过抑制脂肪和骨骼肌PI3K/Akt信号通路，促进葡萄糖的摄取、减轻IR而发挥降血糖药理作用 。但在肝脏组织细胞中，Rg1是否通过抑制炎症反应和氧化应激，影响糖代谢的分子机制不清楚。本研究利用Rg1作用于IR的动物和细胞模型，检测炎症反应和氧化应激相关因子的含量，探讨肝细胞中NOX3、NF-κB和影响葡萄糖输出的p38MAPK和JNK信号通路的相关因子及调节Akt磷酸化的TRB3改变，最终揭示Rg1是否通过抑制炎症反应和氧化应激，进一步降低肝脏葡萄糖输出，从而抑制IR。该研究将为Rg1治疗糖尿病提供科学依据，促进云南三七及其提取物的开发和利用。

糖尿病是威胁人类健康的主要疾病，2型糖尿病占90%以上，胰岛素抵抗是该型疾病的主要诱因。在胰岛素抵抗中，肝脏、脂肪和骨骼肌是导致其发生的主要器官，其中肝脏葡萄糖的输出是诱发胰岛素抵抗（insulin resistance,IR)的主要因素。人参皂苷Rg1是三七和人参中重要的活性成分。研究表明，人参皂苷Rg1可抑制促炎性因子的表达和氧化应激，也能降低血糖，抑制IR。人参皂苷Rg1是否抑制炎症反应和氧化应激，影响肝脏的葡萄糖输出，缓解IR，其机制不完全清楚。. 本研究在高糖高脂诱导的IR动物模型中，检测血糖、胰岛素和计算胰岛素抵抗指数；检测血脂、炎性因子、氧化抗氧化指标。检测NOX3和p38 MAPK、P-p38 MAPK、Akt、P-Akt、JNK、P-JNK、PEPCK、 G6p、GSK等因子的表达。检测 Rg1干预后NOX3和影响肝细胞葡萄糖输出的p38 MAPK途径及JNK途径相关因子的改变，从体内研究探讨Rg1对肝脏葡萄糖输出的影响。. 在IR细胞模型中，确定胰岛素抵抗Hepg2细胞模型的优化条件。检测人参皂苷Rg1对HepG2细胞增殖的影响；人参皂苷Rg1对胰岛素抵抗HepG2细胞葡萄糖消耗量的影响。检测NOX3、p38MAPK、Akt和GSK-3β的表达。检测NOX3、JNK、Akt、PEPCK和G6p的表达。检测Rg1处理后对的糖原累积、NOX3和HepG2细胞葡萄糖输出的p38 MAPK途径和JNK途径相关因子的改变，观察Rg1对p38 MAPK途径和JNK途径相关因子的改变。从体外研究探讨Rg1对HepG2细胞IR模型的葡萄糖输出的影响和可能作用的位点。. 通过在本研究的基础上，探讨人参皂苷Rg1对2型糖尿病大鼠肝脏细胞凋亡的调控以及EGCG调控骨骼肌组织TRB3表达改善胰岛素抵抗的分子机制研究，研究胰岛素的纳米释放等内容，目前由该基金资助发表的相关研究论文10篇，其中SCI收录3篇。培养研究生4名。