Effect of Ubiquinol-10 on the Affinity of LDL to Its Receptor: A Model for Prevention of Atherogenesis

The affinity of low density lipoprotein(LDL) to its receptor is very important, because most of LDL-uptake pathway is done by the LDL receptor and the change in size of LDL particle and the modification in its components may affect the LDL affinity for its receptor. In this study, the effects of a powerful lipid-soluble antioxidant “ubiquinol-10” have been investigated on the affinity of LDL to its receptor. LDL receptor was purified of bovine adrenal tissue. LDL was isolated by sequential density ultracentrifugation from normolipidemic human plasma. Then, LDL was labeled with fluoresein isothiocyanate (FITC) at 4°C for 24 h. Native LDL was incubated with various concentrations of ubiquinol-10 for 2 h. Finally, native LDL(treated with ubiquinol-10) was incubatd with the LDL receptor in the presence of labeled-LDL at 37°C for 30 min. After incubation, the medium was centrifuged at 4000×g for 20 min and the fluorescence intensity(FI) of supernatant from each sample was determined at excitation=495 nm and emission=515 nm. The elevation of FI in each fraction demonstrates increasing the affinity of non-labeled-LDL to its receptor. Our results showed that ubiquinol-10 increased the affinity of LDL to its receptor, and at the concentration of 200 µM it had the greatest effect. These finding raise the possibility that ubiquinol-10 may decrease the effect of LDL in formation of atherosclerotic lesions.