Oxidative modification of lipoproteins in hypertriglyceridemic patients and hypercholesterolemic rabbits in vivo

Many lines of evidence suggest that LDL is oxidized in vivo and that Ox-LDL is present in the artery wall. But the oxidation of VLDL and HDL in vivo h as not yet been reported. In this study, the oxidative modification of seru m LDL, VLDL, and HDL in patients with endogenous hypertriglyceridemia (HTG) and in serum of rabbits fed on high cholesterol diet were made. The serum LDL, VLDL and HDL were isolated by the density gradient ultracentrifugation . The oxidative modification of LDL, VLDL and HDL were identified by agaros e eletrophoresis, absorbance at 234 nm and fluorescence of TBARS. The resul ts showed that serum TC, TG and TBARS in the HTG group (n = 25) and in rabb its fed with a high fat diet (for 12 weeks, n = 8) were significantly highe r than those of the corresponding control groups (normal subjects, n = 25; rabbits fed with a normal diet, n = 8; p < 0.01). The electrophoretic mobil ities of LDL, VLDL and HDL were increased when compared with the controls, and absorbance at 234 nm and TBARS of LDL, VLDL and HDL in the HTG group an d in the high fat diet rabbits were significantly higher than those of the controls (p < 0.01). These results suggest that not only LDL but also VLDL and HDL were oxidatively modified in vivo in the patients with HTG and in t he rabbits fed with a high cholesterol diet.