Background Oxidative injury to the endothelial cells plays an important role in development of atherosclero-sis.Investigation of the mechanisms of oxidative endothelial injury is of great importance.Our previous report has demonstrated that Sirtuin 3(SIRT3)protect cardiomyocytes from oxidative stress-mediated cell death via acti-vating the nuclear factor kappa-B(NF-κB)signaling pathway.However,the role and exact mechanisms of SIRT3 signaling in endothelial hypoxia injury are largely unknown.The present study aimed to investigate the expres-sion of SIRT3,hypoxia-inducible factor 1α(HIF-1α),and NF-KB/TNF-α(tumor necrosis factor-α)in human um-bilical vein endothelial cells(HUVECs)treated by hypoxia.Methods Hypoxia model was established by anox-ic tank and randomly divided into 3 groups:control group,lh hypoxia group,and 3h hypoxia group.3-(4,5-dime-trylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)detected the cell viability under hypoxia condition,and the intracellular reactive oxygen species(ROS)generation was determined by 2',7'-Dichlorodihydrofluorescein diacetate(DCFH-DA).The expression of mRNA and protein of the SIRT3 signaling were detected by real-time quantitative polymerase chain reaction(qPCR)and western blot analysis,respectively.Results Hypoxia treat-ment time-dependently decreased the cell viability,especially in the first hour.ROS production significantly in-creased in the first hour of hypoxia compared with those in the second and the third hour.Hypoxic stimuli signifi-cantly elevated SIRT3 mRNA and protein expression.Furthermore,real-time qPCR results showed that elevated SIRT3 significantly increased the mRNA expression of HIF-1α and NF-KB/TNF-α in lh hypoxia group.Western blot results also showed that elevated SIRT3 significantly increased the protein expression of NF-κB in the lh hy-poxia group.Conclusions The present study indicated that hypoxic stimuli promoted the expression of SIRT3,HIF-1α,and NF-KB/TNF-α,and suggested that SIRT3 signaling pathway may participate in the physiological process of acute ischemic hypoxia stress in human endothelial cells.