Ang-(1-7)与Mas结合促进NIT细胞分泌胰岛素

The binding of Ang-(1-7) and Mas stimulates insulin secretion in NIT cell

目的体外研究Ang-(1-7)对NIT细胞胰岛素分泌的影响及其潜在机制。方法将NIT细胞在不同浓度Ang-(1-7)(10-8～10-3mol/L)培养24 h,ELISA法检测NIT细胞对葡萄糖刺激的胰岛素分泌功能。用RT-PCR法,从NIT细胞中扩增Mas、GLUT-2和TGF-β1基因的全长cDNA序列。将NIT细胞在10-5mol/L Ang-(1-7)条件下培养48 h,QRT-PCR方法检测NIT细胞Mas、GLUT-2及TGF-β1的mRNA表达,Western印迹方法测定NIT细胞Mas、GLUT-2及TGF-β1的蛋白表达。结果 NIT细胞系随着细胞外Ang-(1-7)浓度(10-8～10-3mol/L)的增加胰岛素分泌增加,10-5mol/L Ang-(1-7)组胰岛素分泌量为(8.86±0.53)mIU/L,显著高于对照组(8.06±0.39)mIU/L(P<0.05)。与对照组相比,经10-5mol/L Ang-(1-7)预处理的NIT细胞Mas及GLUT-2的mRNA和蛋白表达上调(P<0.05);相反,经10-5mol/L Ang-(1-7)预处理的NIT细胞TGF-β1的mRNA和蛋白表达水平下降(P<0.05)。结论Ang-(1-7)与Mas结合能够促进NIT细胞分泌胰岛素,这可能与提高NIT细胞摄取葡萄糖的能力、抑制纤维化进程等相关。

Objective To investigate the effects of Ang- （ 1-7 ） and Mas receptor on insulin secretion in NIT cell and their potential mechanism. Methods NIT cells were exposed to Ang-（1-7） of different concentrations （10^-8 - 10^-3 tool/L） for 24 hours. Glucose stimulated insulin secretion by NIT cells was detected with ELISA. The full eDNA sequence of Mas, GLUT-2 and TGF-β1were obtained from NIT cell line using RT-PCR. After NIT cells were exposed to 10^-5 mol/L Ang-（1-7） for 48 hours, Mas, GLUT-2 and TGF-β 1 mRNA expression were estimated by real-time PCR; Meantime, the protein levels of the afore variables were detected by Western blot analysis. Results NIT islet cell line responded to extracellular Ang-（1-7） （ 10^ -8- 10^-3 tool/L） with increased insulin secretion in a concentration dependent manner. The insulin secretion increased significantly in the presence of 10^-5mol/L Ang-（1-7） （8.86±0.53）mIU/L compared to control group （8.06±0. 39）mIU/L） （P 〈0. 05）. In the experiments, compared to control group, the cells preincubated with 10^-5mol/L Ang-（1-7） were up-regulated in Mas gene and protein expression （P 〈 0. 05 ）, and caused a significant stimulation of mRNA and protein expres-sion of GLUT-2 （P 〈0. 05 ）. On the contrary, the result showed a reduction in TGF-β1 mRNA and protein expression （ P 〈 0. 05 ）. ConcLusions The binding of Ang- （1-7） and Mas can stimulate the NIT cells to secrete insulin, probably through its enhancing the ability to intake glucose and inhibit the Droaression of fibrosis.