短肽FLPNF对地塞米松诱导的胰岛细胞凋亡的保护作用

Protective Effect of Oligopeptide FLPNF on Dexamethasone-Induced Apoptosis of Islet Cells

目的探讨短肽FLPNF对地塞米松诱导的胰岛细胞凋亡的保护作用及对葡萄糖刺激胰岛素分泌功能的影响。方法用短肽FLPNF、地塞米松单独及联合处理大鼠胰岛INS-1细胞,CCK-8法检测各组INS-1细胞的增殖活性;ELISA法检测葡萄糖刺激胰岛素分泌功能;TUNEL法观察和评估细胞凋亡情况;流式细胞术检测各组的细胞凋亡率;Western blotting法检测凋亡相关蛋白及Glut2蛋白的表达情况。结果地塞米松抑制了INS-1细胞的生长,细胞损伤明显,可以观察到核皱缩破裂,凋亡率可达(40.6±2.4)%,凋亡相关蛋白Bcl-2的表达明显降低,Bax、caspase-3的表达明显升高,Glut2蛋白的表达明显降低。在联合应用短肽FLPNF后,胰岛细胞的凋亡率降低至(27.2±2.0)%(P <0.001),细胞形态明显改善,凋亡相关蛋白及Glut2的表达明显改善。结论FLPNF具有保护地塞米松诱导的胰岛细胞凋亡的作用,并且能够改善胰岛细胞的葡萄糖刺激胰岛素分泌功能。

Objective To investigate the protective effect of FLPNF and the improvement of glucose-stimulated insulin secretion against dexamethasone-induced apoptosis of islet cells. Methods INS-1 cells were treated with oligopeptide FLPNF and dexamethasone,either separately or in combination. Proliferation of INS-1 cells in each group was assessed with CCK-8 assay and the insulin secretion stimulated by glucose was detected by ELISA. The apoptotic condition of the cells was observed and assessed with TUNEL and the apoptosis rate of each group was detected using flow cytometry. The expression of major target protein molecules related to apoptosis and Glut2 was detected by Western blotting analysis. Results Dexamethasone inhibited the growth of INS-1 cells in the group treated with dexamethasone. Cell damage was obvious with observable nuclear shrinkage and nuclear rupture. In addition,apoptosis rate was found to be 40.6%±2.4%. The expression of the apoptosis-related protein Bcl-2 and Glut2 was significantly reduced,whereas that of Bax and caspase-3 was significantly increased. After the combined treatment of oligopeptide FLPNF and dexamethasone,the results were reversed,and the apoptosis rate declined to 27.2%±2.0%( P < 0.001),cell morphology was improved,and the expression of apoptosis-related protein molecules of islet cells and protein Glut2 was significantly improved. Conclusion FLPNF has the ability of protecting islet cells from dexamethasone-induced apoptosis and improving the glucose-stimulated insulin secretion of islet cells.