Comparative study on the effect of low-dose vitamin E and probucol on the susceptibility of LDL to oxidation and the progression of atherosclerosis in Watanabe heritable hyperlipidemic rabbits.

Publisher Website
Google Scholar
Abstract
The diet of Watanabe heritable hyperlipidemic (WHHL) rabbits was supplemented with a low dose (0.025% [wt/wt]) of the antioxidant vitamin E or probucol. The effect of 6 months of treatment on the susceptibility of low-density lipoproteins (LDLs) to oxidative modification and on established atherosclerotic lesions was studied. Vitamin E administration had no effect on plasma lipid levels; probucol supplementation decreased plasma total cholesterol. Vitamin E levels in plasma and LDL increased threefold in the course of treatment with this antioxidant. Six months of treatment with vitamin E and probucol increased the lag time of conjugated-diene formation of LDL subjected to in vitro oxidation by 54% (P < .001) and 51% (P = .019), respectively. In this LDL-oxidizability assay, only vitamin E reduced the maximal rate of conjugated-diene production (-24%, P < .001). Neither vitamin E treatment nor probucol therapy reduced the amount of thiobarbituric acid-reactive substances in plasma. Vitamin E treatment reduced the specific LDL apolipoprotein B-100 fluorescence (-10%, P = .035) compared with controls. Probucol was without effect on this index of in vivo LDL oxidation. At the end of the 6-month study, the mean +/- SD percentage area of aorta covered with plaques was 58.7 +/- 10.1% in control animals, 62.7 +/- 12.0% in the probucol-treated animals, and 48.9 +/- 13.8% in the animals treated with vitamin E; these differences were not significant. This study demonstrates that at this low dosage, vitamin E is a more effective antioxidant than probucol.