Abstract: Objective To investigate the effect of oxidized low density lipoprotein on the expression of Rictor in cultured vascular endothelial cells. Methods Human umbilical vein endothelial cells were isolated and cultured and incubated with oxidized low density lipoprotein (10, 20, 40, 80mg/L) for 24h. RT-PCR and Western blot were employed to detect the expression of Rictor mRNA and protein. The phosphorylation of Akt and eNOS were analyzed with Western blot. The contents of NO2-/NO3- in the culture medium were measured by nitrate reductase assay. Results Oxidized low density lipoprotein significantly down-regulated expression of Rictor mRNA and protein in endothelial cells (P<0.01) and decreased the amount of rictor-mTOR complex. In endothelial cells transfected with Rictor, increased expression of Rictor enhanced the phosphorylation of Akt and eNOS, and restored endothelial NO production. Conclusions The inhibition of Rictor expression by oxidized low density lipoprotein may play an important role in promoting endothelial dysfunction.

Key words: vascular endothelial cells, oxidized low density lipoprotein, Rictor, eNOS