Objectives 15-Lipoxygenase-1(15-LO) oxidises polyunsaturated fatty acids to a rich spectrum of biologically active metabolites, and its deregulation has been reported involved in the development of atherosclerosis. A series of studies demonstrated atorvastatin attenuates endothelial dysfunction. But the relationship between 15-LO and atorvastatin has not been fully investigated. The goal of our study was to evaluate whether 15-LO involved in the improvement of endothelial function by atorvastatin.
Methods A model of oxidised low-density lipoprotein (ox-LDL)-induced injury human umbilical vein endothelial cells (HUVECs) was established to evaluate the protective role of atorvastatin. Experiments were performed by using HUVECs treated with and without lentiviral SiRNA-15-lipoxygenase-1(Len-SiRNA-15LO) or lentiviral-15-lipoxygenase-1 (Len-15-LO) or lentiviral-green fluorescence protein (Len-GFP), the efficacy of gene transefer was assessed with flow cytometry (FCM) at 48h after transfection. Expression of 15-LO was determined with western blot. Cells were dived into 6 groups: control, oxidised low-density lipoprotein (ox-LDL), ox-LDL mixed with atorvastatin, Len-GFP with ox-LDL and atorvastatin, Len-SiRNA-15LO with ox-LDL and atorvastatin, Len-15-LO with ox-LDL and atorvastatin. Nitric oxide (NO) production was measured by griess method. Nitric oxide synthase3 (eNOS) and intracellular adehension molecule-1 (ICAM-1) protein expression levels were observed with western blot.
Results 15-LO expression levels (0.712 ± 0.081 vs1.006 ± 0.023, P < 0.01) were decreased significantly in ox-LDL mixed with atorvastatin group, when compared with ox-LDL group. When compared with normoxic cultures, transfection with Len-SiRNA-15LO knocked down protein expression (0.193 ± 0.135 vs 1.415 ± 0.178, P < 0.01), while Len15-LO significantly upregulated 15-LO protein expression (2.632 ± 0.430 vs 0.255 ± 0.188, P < 0.01). Comparing with control group eNOS protein levels (0.280 ± 0.221 vs 1.597 ± 0.130, P < 0.01) and NO production (1.713 ± 0.175 vs 4.787 ± 0.240, P < 0.01) were decreased significantly in ox-LDL group and ICAM-1 (1.790 ± 0.284 vs 0.560 ± 0.069, P < 0.01) were increased significantly. In comparison with ox-LDL mixed with atorvastatin group, eNOS expression levels (1.950 ± 0.085 vs 1.070 ± 0.056, P < 0.01) were increased significantly in Len-SiRNA-15LO with ox-LDL and atorvastatin group,but lower than that in Len-15LO with ox-LDL and atorvastatin group (0.270 ± 0.121vs1.070 ± 0.056, P < 0.01), NO production (4.397 ± 0.539 vs 2.733 ± 0.170, P < 0.01) were increased significantly in Len-SiRNA-15LO with ox-LDL and atorvastatin group, but lower than that in Len-15LO with ox-LDL and atorvastatin group (1.553 ± 0.059 vs 2.733 ± 0.170, P < 0.01); ICAM-1(0.320 ± 0.053 vs0.877 ± 0.081, P < 0.05) were decreased significantly in Len-SiRNA-15LO with ox-LDL and atorvastatin group, but higher than that in Len-15LO with ox-LDL and atorvastatin group (2.007 ± 0.500 vs 0.877 ± 0.081, P < 0.01). It was showed that atorvastatin significantly restored the decrease in eNOS expression levels, NO production and the increased 15-LO, ICAM-1 levels induced by ox-LDL. Knockdown the 15-LO expression enhanced atorvastatin’s protective affects but the over expression of 15-LO reduced the protective role.
Conclusions Our results demonstrated that low expression of 15-Lipoxygenase-1 may be involved in atorvastatin’s benefits on endothelial function.