高浓度葡萄糖对体外培养小鼠胰岛细胞NF-κB的表达及细胞凋亡的影响

目的:探讨核因子κB（NF-κB）在高浓度葡萄糖诱导胰岛细胞凋亡中的作用。方法：对分离纯化的小鼠胰腺胰岛细胞进行体外培养，按DMEM培养液里葡萄糖浓度不同，分为6组：G1组（5.6 mmol?L^-1葡萄糖）、G2组（7.8 mmol?L^-1）、G3组（11.1 mmol?L^-1）、G4组（16.7 mmol?L^-1）、 G5组(22.2 mmol?L^-1)及G6组（27.6 mmol?L^-1）。采用放射免疫法检测各组胰岛细胞胰岛素分泌水平；免疫组织化学染色法检测NF-κB活性；免疫荧光法检测细胞色素C释放和细胞核染色检测细胞凋亡。结果：当葡萄糖浓度5.6～11.1 mmol?L^-1时，随着葡萄糖浓度升高，胰岛细胞胰岛素分泌逐渐增加（P<0.05)，NF-κB的活性逐渐增加（P<0.05)，但此时细胞凋亡未见显著的变化（P>0.05)，细胞色素C释放的组间比较差异无显著性（P>0.05)。当葡萄糖浓度≥16.7 mmol?L^-1时，与葡萄糖浓度≤11.1mmol?L^-1各组比较， NF-κB表达明显增加，细胞色素C的释放也逐渐增强（P<0.05)，胰岛细胞凋亡百分率同时也呈明显增加趋势（P<0.05）。结论：高浓度葡萄糖可以诱导胰岛细胞NF-κB表达增加，细胞色素C释放增强，同时诱导胰岛细胞凋亡，提示NF-κB的激活与胰岛细胞凋亡可能存在必然的联系，抑制NF-κB活性可能对于保护胰岛细胞有重要作用。

Effects of high glucose on expression of NF-kB in mouse islet cells and apoptosis in vitro

Objective To study the role of NF-kappaB( NF-κB) on islet cell apoptosis in high concentration glucose in vitro.Methods Pancreatic islet cells were isolated from Kunming mice and these cells were cultivated in medium with different concerntrations of glucose: G1 (5.6 mmol·L-1),G2(7.8 mmol·L-1),G3(11.1 mmol·L-1),G4(16.7 mmol·L-1),G5(22.2 mmol·L-1),G6(27.6 mmol·L-1).After the islet cells were cultivated for 72 h,insulin secretion was evaluated by radio-immunity technique.The NF-κB expression was detected by immunocytochemistry and cytochrome C(Cyt.C) release was detected by immunofluorescence technique.Apoptosis of islet cells was determined by Hoechst33342 assay. Results Insulin secretion was enhanced and NF-κB activity was increased(P<0.05)when the concentrations of glucose were 5.6-11.1 mmol·L-1,but Cyt.C release and apoptosis didn’t change. When the concentration of glucose exceeded 16.7 mmol·L-1,the apoptotic percentages of islet cells were increased signficantly accompanying with the glucose concentration elevation compared with G1,G2 and G3 groups(P<0.05),the NF-κB activity and Cyt.C relesae were significantly increased (P<0.05).Conclusion High glucose can induce the apoptosis of islet cells and decrease insulin secretion,enhance the activity of NF-κB and Cyt C release.It suggests that the activation of NF-κB may be related to apoptosis of islet cells,and the inhibition of NF-κB may protect islet cells.