Résumé
Aim To investigate the protective effects of sphingosine 1-phosphate ( S1 P ) postconditioning on hypoxia/reoxygenation( H/R) injury in human umbili-cal vein endothelial cells ( HUVEC ) and its mecha-nisms. Methods HUVECs cells were divided into five groups: normal ( control) group, S1P low concentra-tion group ( L ) , S1 P medium concentration group (M), S1P high concentration group ( H) and H/R group. MTT method was used to measure cell survival. Using flow cytometric analysis, the rate of cell apopto-sis was determined. The activities of total superoxide dismutase ( T-SOD) , copper/zinc superoxide dismuta-se ( CuZn-SOD ) , manganese superoxide dismutase ( Mn-SOD) activity, nitric oxide ( NO) and malondial-dehyde ( MDA ) content in cell culture medium were measured with colorimetry. Mitochondrial membrane potential in cells was observed with fluorescence micro-scope. Bax/Bcl-2, eNOS protein expression levels in HUVECs cells were observed with Western blot. Re-sults Compared with H/R group, S1P low, medium and high concentrations in the intervention group could significantly increase the cell survival rate after H/R injury, and increase activity of T-SOD, CuZn-SOD, Mn-SOD and decrease content of MDA. Moreover, S1 P could significantly increase NO content and in-crease eNOS protein expression, decrease apoptosis rate and inhibit the reduction of mitochondrial mem-brane potential. Conclusions S1P can decrease cell apoptosis rate of HUVECs after H/R injury with a cer-tain concentration dependence. The protection of S1P for cell apoptosis of HUVECs after H/R injury may be related to decreasing the intracellular MDA content and improving intracellular SOD activity, increasing mito-chondrial membrane potential and enhancing expres-sion of Bcl-2, anti-apoptotic protein.