探讨法尼酯X受体通过调控胰岛B细胞TRPA1及钙通道参与RYGB促胰岛素分泌的作用

发布时间：2018-04-24 23:14

本文选题：胃旁路手术 + 法尼酯X受体　；参考：《深圳大学》2017年硕士论文

【摘要】：胰岛B细胞分泌的胰岛素是机体降低血糖的唯一激素,胰岛B细胞功能障碍所致的胰岛素水平降低直接导致糖尿病的发生发展。B细胞分泌胰岛素是一个精确而复杂的调控过程,葡萄糖是体内促进胰岛素分泌的主要因素,它通过胰岛B细胞膜转运体GLUT2转入细胞,在线粒体代谢产生ATP,提高胞浆ATP/ADP比值,关闭细胞膜ATP敏感的钾通道(KATP通道),导致细胞内带正电荷的钾离子增多,细胞膜去极化,开发电压门控钙通道,钙离子内流使细胞内钙离子浓度升高,诱发胰岛素囊泡的出胞。临床和基础研究发现胃旁路手术(RYGB)能显著纠正2型糖尿病高血糖症状,其效应与增加胰岛素分泌相关。我们课题组的前期工作发现RYGB增加胰岛素分泌的同时,伴有胰岛B细胞法尼酯X受体(Farnesoid X receptor,FXR)的升高。FXR是胆汁酸受体。作为核受体,FXR在糖脂代谢的调解中发挥重要作用。本论文利用全细胞电生理技术,在胰岛B细胞中记录了葡萄糖诱发的动作电位和膜电位,且研究了胰岛B细胞上钙电流的大小。利用Q-PCR检测和western blot等技术检测了胰岛中钙通道和TRPA1通道在mRNA和蛋白质水平的表达。利用ELASA技术检测了INS-1E细胞系和小鼠胰岛在葡萄糖刺激下的胰岛素分泌能力。通过以上这些实验技术,我们主要得到了以下研究结果:(1)FXR通过增进胰岛B细胞TRPA1的表达,提高B细胞对葡萄糖刺激的敏感性,继而增进糖刺激的胰岛素分泌;(2)FXR通过增进胰岛B细胞L-型钙通道转录水平,提高B细胞钙通道的表达,增大糖刺激所致的钙电流,导致胰岛素分泌增大。以上结果阐明RYGB增进胰岛素分泌的机制,为临床治疗糖尿病提供新的科学依据及新的治疗靶点。
[Abstract]:Insulin secreted by islet B cells is the only hormone that reduces blood glucose. The decrease of insulin level caused by islet B cell dysfunction directly leads to the occurrence and development of diabetes. B cells secrete insulin is a precise and complex regulatory process. Glucose is the main factor that promotes insulin secretion in vivo. It is transferred into cells through islet B cell membrane transporter GLUT2, which produces ATP in mitochondria metabolism and enhances the ratio of cytoplasmic ATP/ADP. Closing the K + channel sensitive to ATP leads to the increase of positively charged potassium ions in the cell membrane, depolarization of cell membrane, development of voltage-gated calcium channel, and the increase of intracellular calcium ion concentration by calcium ion influx, which induces the release of insulin vesicle. Clinical and basic studies showed that RYGBcan significantly correct hyperglycemia in type 2 diabetes mellitus, and its effect is related to the increase of insulin secretion. Our previous work found that RYGB increased insulin secretion accompanied by the increase of Farnesoid X receptor FXR. FXR was a bile acid receptor. As a nuclear receptor, FXR plays an important role in the regulation of glucose and lipid metabolism. In this paper, the action potential and membrane potential induced by glucose in islet B cells were recorded by whole-cell electrophysiological technique, and the magnitude of calcium current on islet B cells was studied. The expression of calcium channel and TRPA1 channel in pancreatic islets at the level of mRNA and protein were detected by Q-PCR detection and western blot techniques. The insulin secretion ability of INS-1E cell line and islet of mice stimulated by glucose was detected by ELASA technique. Through these experimental techniques, we have obtained the following results: 1. FXR enhances the sensitivity of B cells to glucose stimulation by enhancing the expression of TRPA1 in islet B cells. The insulin secretion induced by glucose stimulation was increased by increasing the transcription level of L- type calcium channel, increasing the expression of calcium channel and increasing the calcium current induced by glucose stimulation, which led to the increase of insulin secretion. These results indicate that RYGB enhances insulin secretion and provides a new scientific basis and new therapeutic target for the clinical treatment of diabetes mellitus.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R587.1

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