engleski

Inhibitory effect of gangliosides on copper-induced oxidation of human LDL and VLDL

Majority of serum gangliosides is from the liver origin and associated with lipoproteins. Their role in atherogenesis has been proposed, but the mechanism is still not well elucidated. We have demonstrated that exogenous gangliosides are capable to protect erythrocyte filterability impairment induced by calcium loading. The aim of this study was to establish the possible influence of exogenous gangliosides on the Cu-induced oxidation of LDL and VLDL lipoproteins in vitro. LDL and VLDL were isolated by ultracentrifugation from blood of the healthy donors. Oxidation was performed using 100 micrograms LDL protein/ml and 5 mikromoles of copper sulphate, or 25 micrograms VLDL protein/ml and 17 micromoles copper sulphate in 0.01M PBS, pH 7.4, at 30 C during 300 minutes. Lipoprotein samples were incubated without and with the presence of gangliosides (Type III or GD1A ; Sigma), at the concnetration of 10 and 100 mocromoles. Formation of conjugated dienes were measured at 234 nm. By the analysis of the diene formation kinetics, it was demonstrated that gangliosides protect LDL and VLDL against peroxidation. Lag time duration was prolonged, whereas rate of diene formation was decreased by the presence of gangliosides both in LDL and VLDL oxidation. Present data demonstrate the protective effect of gangliosides agains copper- induced peroxidative modification of LDL and VLDL in vitro.

gangliosides; induced oxidation; LDL; VLDL

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