GLP-1受体激动剂Exendin4对胰岛β细胞胰岛素和IAPP分泌模式的影响

Effect of GLP-1 receptor agonist Exendin4 on secretion pattern of insulin and islet amyloid polypeptide in islet beta cells

目的:探讨GLP-1受体激动剂(GLP-1RA)Exendin4作用下胰岛β细胞的胰岛素及胰淀粉样多肽(IAPP)的分泌模式。方法:观察小鼠胰岛瘤细胞系MIN6细胞在不同浓度Exendin4作用不同时间后的细胞形态的变化;利用MTT实验检测MIN6细胞在不同干预后的细胞活性的变化;采用葡萄糖刺激胰岛素分泌实验,检测MIN6细胞在不同干预后培养液上清中的胰岛素和IAPP分泌量的变化;采用荧光定量PCR(RT-PCR)检测各组MIN6细胞的胰岛素和IAPP m RNA表达水平的变化。结果:与正常对照组比较,Exendin4组的细胞数量增加,贴壁牢固,形态正常;细胞活性随Exendin4作用浓度以及作用时间的增加而显著增加,具有一定的浓度及时间依赖性;胰岛素和IAPP的分泌水平随Exendin4作用浓度以及作用时间的增加而显著增加,具有一定的浓度及时间依赖性,而IAPP/胰岛素的比值随作用浓度以及作用时间的增加而减小;胰岛素和IAPP m RNA水平均随Exendin4作用浓度以及作用时间的增加而上调,具有一定的浓度及时间依赖性,IAPP/胰岛素m RNA比值随作用浓度以及作用时间的增加而减小。结论:Exendin4作用于MIN6细胞可增加细胞数量和细胞活性,改善细胞状态,保护胰岛细胞功能;并且可引起胰岛素以及IAPP分泌水平增加,胰岛素和IAPP m RNA表达水平增加,而IAPP/胰岛素比值下降。

Objective： To explore the effect of GLP-1 receptor agonist （GLP-1RA） Exendin4 on insulin and islet amyloid polypeptide （IAPP） secretion pattern. Methods： Cell morphology of MIN6 cells was observed after treated with different concentrations of GLP-1 receptor agonist Exendin4 for different time periods. Cell viability of MIN6 cells was detected after different interventions respectively by MTT assay. Glucose-stimulated secre- tion levels of insulin and islet amyloid polypeptide were examined in culture supernatant of MIN6 cells and RT- PCR was used for detecting the expression levels of insulin mRNA and IAPP mRNA after different interventions respectively. Results： Compared with the control group, Exendin4 group exhibited much stronger adherence to the culture dish, with normal morphology and increasing cell numbers. There was a significant increase of cell vi- ability in MIN6 cells treated with Exendin4, which displayed dose- and time-dependent pattern. Insulin and islet amyloid peptide secretion levels increased accordingly, while the ratio of IAPP/insulin decreased. The mRNA expression levels of insulin and IAPP of MIN6 cells were increased with treatment of Exendin4, which also dis- played dose- and time-dependent pattern, while the ratio of IAPP/insulin mRNA correspondingly. Conclusion： Exendin4 increases the number and cell viability of M1N6 cells. Exposure to Exendin4 can increase insulin and IAPP secretion levels, and mRNA expression levels of insulin and IAPP as well, while the ratio of IAPP/insulin is deceased accordingly.