High level of glucose induced apoptosis in human endothelial cells and its mechanism of JNK and AKT signaling pathways

Objective To investigate the signaling pathway of high level of glucose-induced apoptosis in human umbilical vein endothelial cells (HUVECs). Methods HUVECs were incubated with physiological concentration of glucose (5 mmol/L) (NG), high glucose (30 mmol/L)(HG) and high glucose combined with SP600125(HG+I) for 72 hours. Apoptosis of HUVECs was observed in a fluorescence microscope by Hoechst 33258 stain, and quantitied by flow cytometry using annexin V-FITC stain. The level of p-JNK, p-c-JUN and p-AKT was evaluated by western blot. Results Treatment of HUVECs with high glucose resulted in a significant increase in apoptotic cells comparing to a physiological concentration (13.31% vs 5.69%, P0.01). Incubation of HUVECs with high concentration of glucose for 72 hours increased the phosphorylation of JNK and c-JUN significantly (P0.05, vs NG), while decreased the level of p-AKT markedly(P0.01, vs NG). After treated with SP600125, the level of p-JNK and p-c-JUN (P0.05, vs HG) decreased, while the level of p-AKT increased (P0.01, vs HG),and the apoptosis of HUVECs induced by high glucose was inhibited (8.38%, P0.01, vs HG). Conclusion High concentration of glucose could induce HUVECs apoptosis, probably through increasing the activation of JNK, the downstream c-jun, and inhibition of the activation of AKT. The activation JNK could regulate AKT pathway.