Abstract: Objective To investigate whether exogenous hydrogen sulfide (H2S) inhibits the high-glucose (HG)-induced injury by modulating leptin/leptin receptor (LEPR) signal pathway in human umbilical vein endothelial cells (HUVECs). Methods HUVECs were treated with 40 mmol/L glucose for 3-24 h, and the cell viability was examined by CCK-8 assay. The changes of cell morphology and the number of apoptotic cells were assessed by Hoechst 33258 nuclear staining followed by photofluorography. The intracellular levels of reactive oxygen species (ROS) was detected by DCFH-DA staining followed by photofluorography. Mitochondrial membrane potential (MMP) was determined by Rhodamine 123 (Rh123) staining and photofluorography. The expression levels of leptin and LEPR protein were measured by Western blotting. Results The expression of leptin and LERP in HUVECs began to significantly increase at 3 h after HG exposure and reached the peak levels at 9 h (P<0.01). Pretreatment of HUVECs with 400 μmol/L sodium hydrosulfide (H2S donor) for 30 min inhibited HG-induced increase in leptin and leptin receptor expressions in HUVECs (P<0.01). Pretreatment of HUVECs with 400 μmol/L NaHS for 30 min or 50 ng/mL leptin antagonists (LA) for 1 h obviously alleviated HG-induced injury by increasing cell viability, decreasing cell apoptosis and lowering accumulation of intracellular ROS and MMP loss (P<0.01). Conclusion Exogenous H2S protects against HG-induced injury by inhibiting leptin/LEPR pathway in HUVECs.