15Lipoxygenase Activity: Involve In The Pathway Of Endothelial Function Improvement By Atorvastatin

Aims: The aim of this study is to test whether15-lipoxygenase (15LO)is involved in the improvement of endothelial function caused byatorvastatin.Method: A model of oxidized low-density lipoprotein(ox-LDL)-induced injury in human umbilical vein endothelial cells wasestablished to evaluate the protective role of atorvastatin. Experiments wereperformed on human umbilical vein endothelial cells treated with andwithout lentiviral siRNA-15-lipoxygenase-1(siRNA-15LO), lentiviral15-lipoxygenase-1(Lv-15LO) or lentiviral green fluorescence protein(Lv-GFP). The efficacy of gene transfer was assessed with flow cytometry at48h after transfection. Expression of15LO was determined with Westernblotting. Cells were divided into6groups according to treatments: control,ox-LDL, ox-LDL mixed with atorvastatin, Lv-GFP with ox-LDL andatorvastatin, siRNA-15LO with ox-LDL and atorvastatin, and Lv-15LO withox-LDL and atorvastatin. Nitric oxide production was measured by Griess method. Endothelial nitric oxide synthase and intracellular adhesionmolecule-1protein expression levels were measured with Western blotting.Result: Compared with the control group, endothelial nitric oxidesynthase protein levels and nitric oxide production in ox-LDL group weredecreased significantly,（0.41±0.03vs1.00, P<0.01），（0.28±0.22vs1.60±0.13, P<0.01），while intracellular adhesion molecule-1proteinlevels in ox-LDL group were increased significantly（4.45±0.23vs1.00,P<0.01）,（1.79±0.28vs0.56±0.07, P<0.01）. Endothelial nitric oxidesynthase expression levels in the group of ox-LDL mixed with atorvastatinwere significantly lower than that in the group of siRNA-15LO with ox-LDLand atorvastatin（1.67±0.59vs3.43±0.91, P<0.05），（1.07±0.06vs1.95±0.09, P<0.05）, but higher than that in the group of Lv-15LO withox-LDL and atorvastatin（1.67±0.59vs0.59±0.15,P<0.05），（1.07±0.06vs0.27±0.12, P<0.05）; Nitric oxide productionin the group of ox-LDL mixed with atorvastatin was significantly lower thanthat in the group of ox-LDL mixed with atorvastatin（2.73±0.17vs4.40±0.54, P<0.01）, but higher than that in the group of Lv-15LO withox-LDL and atorvastatin（2.73±0.17vs1.55±0.06, P<0.01）; ICAM-1levels in the group of atorvastatin with ox-LDL and atorvastatin weresignificantly lower than that in the group of Lv-15LO with ox-LDL andatorvastatin（0.71±0.01vs1.61±0.06, P<0.05），（0.88±0.08vs2.01±0.50, P<0.05）, but higher than that in the group of siRNA-15LO with ox-LDL and atorvastatin（0.71±0.01vs0.25±0.05,P<0.05），（0.88±0.08vs0.32±0.05, P<0.05）.Conclusion: Our data showed that atorvastatin significantly rescuedthe decrease in endothelial nitric oxide synthase expression, promoted nitricoxide production, and increased ICAM-1levels which were reduced byox-LDL. Knockdown of15LO expression enhanced the protective effect ofatorvastatin, but the overexpression of15LO reduced the protective role.Our results demonstrated that the expression of15-lipoxygenase might beinvolved in the effect of atorvastatin on endothelial function.