Nicorandil Alleviates The Oxidative Stress In Endothelial Cells By Regulating The Thioredoxin Expression

PartⅠ Establishment and evaluation of the H₂O₂-inducedoxidative stress model in HUVECsObjective: To establish and evaluate the cell model of H₂O₂-induced oxidativestress in HUVECs.Methods: HUVECs were divided into6groups. HUVECs were exposed to50μmol/L H₂O₂，100μmol/LH₂O₂，200μmol/LH₂O₂，400μmol/LH₂O₂for6hours，12hours，24hours. After incubation, HUVECs were washed, placed inphenol-red-free and serum-free DMEM. Intracellular ROS were visualized by usingan inverted fluorescence microscope （Leica RX-DA），cells were treated with theabove dye （DCFH-DA in HBSS） and were measured by FACS analysis，fluorescence intensity of the total culture was used as an indicator.Results: H₂O₂exposurment increased ROS formation in HUVECs， differentconcentrations along with different times induced different ROS formation inHUVECs. Treatment with100μmol/L H₂O₂for24h markedly increased intracellularROS levels in HUVECs under static culture conditions. And then, intracellular ROSlevels were decreased and the apoptosis of HUVECs were increased.Conclusion: Treatment with100μmol/L H₂O₂for24hours markedly increasedintracellular ROS levels in HUVECs under static culture conditions, and the cellmodel of oxidative stress in HUVECs were established. PartⅡ Nicorandil alleviates the oxidative stress in endothelialcells by regulating the thioredoxin expressionObjective: The purpose of this study was to estimate the influence of nicorandilin human umbilical vein endothelial cells oxidative stress induced by H₂O₂and theexpression of thioredoxin–one of the antioxidant systems in cells.Methods: Human umbilical vein endothelial cells were randomly allocated intofour groups:①control group;②oxidative stress cell model group;③oxidativestress cell model group with nicorandil;④oxidative stress cell model group withnicorandil as well as a KATPchannel blocker glibenclamide. HUVECs weremaintained in a humidified5%CO₂in air incubator at37℃. Oxidative stress wasassessed by the formation of ROS through Flow Cytometry（FCM）. ThioredoxinmRNA levels were measured by real-time PCR, thioredoxin expression was analyzedby western blot.Results: Nicorandil treatment significantly attenuated ROS formation of humanumbilical vein endothelial cells induced by H₂O₂, up-regulated the mRNA levels ofthioredoxin, and elevated the production of thioredoxin protein. Furthermore, theKATPchannel blocker glibenclamide abolished nicorandil-mediated reduction ofreactive oxygen species as well as mRNA level of thioredoxin.Conclusions: The present study has revealed that nicorandil attenuatesH₂O₂-induced ROS formation in human umbilical vein endothelial cells throughincreased the production of thioredoxin.