基于TGR5-mTOR信号通路的半夏-黄连调节肠道GLP-1分泌防治糖尿病胃轻瘫机制研究

The disorder of gastrointestinal hormone GLP-1 secretion is closely associated with diabetic gastroparesis. Low GLP-1 secretion presents under hyperglycemic conditions and high GLP-1 secretion appears under hypoglycemic conditions result in the delayed gastric emptying, which may be a new mechanism in the pathogenesis of diabetic gastroparesis. Banxia-Huanglian was a representative drug pair in effective formula in treatment and prevention of DGP. The preliminary study found that Banxia-Huanglian could promote GLP-1 secretion under hyperglycemic conditions and inhibit GLP-1 secretion under hypoglycemic conditions. With TGR5-mTOR signaling pathway as the key point in regulating intestinal GLP-1 secretion, we further propose a hypothesis that Banxia-Huanglian regulates intestinal GLP-1 secretion under different conditions based on TGR5-mTOR signaling pathway in the prevention and treatment of diabetic gastroparesis. Combining the overall effect with the molecular mechanism, this research intends to investigate the effects of Banxia-Huanglian on the delayed gastric emptying of DGP, the GLP-1 secretion, and the TGR5-mTOR signaling pathway through the use of WB, RT-PCR, ELISA and other technologies. Moreover, this study will use the specific inhibitor strategy to demonstrate the participation of the TGR5-mTOR signaling pathway in GLP-1 secretion. To clarify the mechanisms for the improvement of Banxia-Huanglian for preventing and treating DGP, which would supply scientific evidence for the traditional Chinese medicine in the prevention and treatment of DGP.

胃肠激素GLP-1紊乱与糖尿病胃轻瘫的密切相关，高血糖状态下低GLP-1分泌，低血糖状态下高GLP-1分泌，导致胃排空延迟可能是糖尿病胃轻瘫的新机制。半夏-黄连是临床有效防治糖尿病胃轻瘫的代表药对，前期基础表明半夏-黄连能够促进高血糖状态下GLP-1分泌，抑制低血糖状态下GLP-1分泌。基于TGR5-mTOR信号通路对GLP-1调控的重要作用，进一步提出假设：半夏-黄连通过TGR5-mTOR信号通路调控不同血糖状态下的肠道GLP-1分泌，发挥防治糖尿病胃轻瘫的效应。拟应用WB、RT-PCR、ELISA等技术，整体效应与分子机制相结合，研究半夏-黄连对高血糖状态和低血糖状态的DGP的效应及对肠道L细胞GLP-1及TGR5-mTOR信号通路的影响；并利用特异性抑制剂，反证作用环节和靶分子。阐明半夏-黄防治糖尿病胃轻瘫的作用机制，为中医药防治糖尿病胃轻瘫提供科学依据。

半夏-黄连是临床有效防治糖尿病胃轻瘫的代表药对，胃肠激素GLP-1紊乱导致胃排空延迟是糖尿病胃轻瘫的新机制。本课题利用糖尿病胃轻瘫大鼠（高血糖和低血糖）模型，发现半夏-黄连药能显著抑制糖尿病胃轻瘫模型的大鼠空腹血糖、胃排空、肠推进，改善MLT，VIP，SS等胃肠激素水平。半夏-黄连还能够调节糖尿病胃轻瘫状态下的高血糖和低血糖水平下的GLP-1水平，提示半夏-黄连药对在高血糖时具有降糖作用，同时还能防止糖尿病胃轻瘫状态下的急性低血糖的发生，该作用与GLP-1的水平密切相关。基于TGR5-mTOR信号通路，分别研究半夏-黄连对高葡萄糖和低葡萄糖刺激条件下的肠道L细胞GLP-1分泌影响和相关蛋白及基因表达，显示半夏-黄连对不同葡萄糖刺激下的STC-1细胞GLP-1分泌的效应与TGR5-mTOR信号通路密切相关。成分分析和效应研究发现小檗碱可能是其中的有效成分之一。通过对半夏-黄连在糖尿病胃轻瘫中的效应及相关机制研究，更好的阐述中医药在临床防治糖尿病胃轻瘫的特色和优势。