Effects of resveratrol on NO secretion stimulated by insulin and its dependence on SIRT1 in high glucose cultured endothelial cells

To investigate the effects of resveratrol on the secretion of NO induced by insulin in high glucose cultured primary human umbilical vein endothelial cells (HUVEC). HUVEC were treated with 1 mu mol/l resveratrol for 24 h before cultured in high glucose medium for 48 h, then all cells were stimulated by 100 nmol/l insulin for 30 min. Method based on nitric acid reductase was used to analyze the NO contents in the supernatant. Cells were collected to analyze the expression of eNOS, endothelin-1, E-selectin, and SIRT1. In order to investigate the dependence of resveratrol on SIRT1, the effects of resveratrol on cells treated by SIRT1 siRNA were also examined. Compared with control cells, high glucose decreased the secretion of NO induced by insulin. Resveratrol treatment increased the expression of SIRT1 and the secretion of NO. After interfering the expression of SIRT1 using SIRT1 siRNA, the effects of resveratrol on the NO secretion induced by insulin was impaired. Resveratrol also counteracted other pro-atherosclerotic effects of high glucose, including the up-regulating roles of high glucose on the expression of endothelin-1 mRNA and E-selectin mRNA, and the down-regulating roles of high glucose on the expression of eNOS mRNA and the basal NO secretion without the stimulating of insulin. Resveratrol can improve the NO stimulating function of insulin in high glucose cultured HUVEC in SIRT1-dependent manner. Thus, our results imply that resveratrol may have the preventive roles of atherosclerosis in diabetic patients.