engleski

Inhibition of low density lipoprotein oxidation by gangliosides

Amphipathic gangliosides (sialic acid-containing glycosphingolipids) are normal constituents of lipoproteins. Most of gangliosides in plasma lipoproteins are associated with LDL. Alterations in the concnetration or pattern of lipoprotein-associated gangliosides could be implicated in the development of atherosclerosis. Aim of this study wa to examine the possible antioxidant capacity of exogenous gangliosides on LDL oxidation in vitro. LDL was isolated by ultracentrifugation from blood of five healthy human donors. LDL (100 micrograms protein/ml) was incubated with 5 micromoles copper sulphate in 0.01 PBS buffer, pH 7.4 at 30 C for 300 minutes. The reaction mixture was incubated without and with gangliosides (Sigma, St. Louis, USA) composed of 21% GM1, 40% GD1A, 16% GD1B and 19% GT1B. Conjugated diene formation was measured by monitoring the absorbance at 234 nm. The kinetics analysis of conjugated diene production revealed that 100 micromoles of gangliosides prolonged the lag time of conjugated diene formation (from 184.0+109.2 to 238+101.8 min.)The oxidation propagation rate (change in absorption/min) was significantly decreased (from 104.0+24.1 to 62.0+8.4 Abs.10/min; p<0.05). These results demonstrate that gangliosides may reduce copper-induced LDL oxidation in vitro.

low density lipoprotein; oxidation; ganglioside

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