Objective:To investigate whether ginsenoside Rb1 (Rb1) can protect human umbilical vein endothelial cells (HUVECs) against high glucose-induced apoptosis and examine the underlying mechanism.Methods:HUVECs were divided into 5 groups:control group (5.5 mmol/L glucose),high glucose (HG,40 mmol/L) treatment group,Rb1 (50 μ mol/L) treatment group,Rb1 plus HG treatment group,and Rb1 and 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP,16 μ mol/L) plus HG treatment group.Cell viability was evaluated by cell counting kit-8 assay.Mitochondrial and intracellular reactive oxygen species were detected by MitoSox Red mitochondrial superoxide indicator and dichloro-dihydro-fluorescein diacetate assay,respectively.Annexin V/propidium iodide staining and fluorescent dye staining were used to measure the apoptosis and the mitochondrial membrane potential of HUVECs,respectively.The protein expressions of apoptosis-related proteins[Bcl-2,Bax,cleaved caspase-3 and cytochrome c (Cyt-c)],mitochondrial biogenesis-related proteins[proliferator-activated receptor gamma coactivator 1-alpha,nuclear respiratory factor-1 and mitochondrial transcription factor A)],acetylation levels of forkhead box O3a and SOD2,and sirtuin-3 (SIRT3) signalling pathway were measured by immunoblotting and immunoprecipitation.Results:Rb1 ameliorated survival in cells in which apoptosis was induced by high glucose (P＜0.05 or P＜0.01).Upon the addition of Rb1,mitochondrial and intracellular reactive oxygen species generation and malondialdehyde levels were decreased(P＜0.01),while the activities of antioxidant enzymes were increased (P＜0.05 or P＜0.01).Rb1 preserved the mitochondrial membrane potentialand reduced the release of Cyt-c from the mitochondria into the cytosol(P＜0.01).In addition,Rb1 upregulated mitochondrial biogenesis-associated proteins (P＜0.01).Notably,the cytoprotective effects of Rb1 were correlated with SIRT3 signalling pathway activation (P＜0.01).The effect of Rb1 against high glucose-induced mitochondria-related apoptosis was restrained by 3-TYP (P＜0.05 or P＜0.01).Conclusion:Rb1 could protect HUVECs from high glucose-induced apoptosis by promoting mitochondrial function and suppressing oxidative stress through the SIRT3 signalling pathway.