Probucol improves endothelial-dependent relaxation and decreases vascular superoxide production in cholesterol-fed rabbits.

Inoue N, Ohara Y, Fukai T, Harrison DG, Nishida K
Am J Med Sci. 1998 315 (4): 242-7

PMID: 9537638 · DOI:10.1097/00000441-199804000-00005

Recent data indicate that hypercholesterolemia increases endothelial superoxide anion (.O2-) production, and that this diminishes the bioactivity of nitric oxide produced in the endothelium. Probucol, a drug commonly employed for treatment of hypercholesterolemia, has antioxidant properties and inhibits oxidation of low density lipoproteins in vitro. We tested the hypothesis that probucol would decrease vascular .O2- production and improve endothelium-dependent relaxations in cholesterol-fed rabbits. Rabbits were divided into four groups: 1) a control group fed a standard diet; 2) a probucol group fed a standard diet containing 0.3% probucol; 3) a hypercholesterolemic group fed a diet containing 0.5% cholesterol; 4) a hypercholesterolemia-probucol group fed a diet containing 0.5% cholesterol and 0.3% probucol. The cholesterol-rich diet markedly increased plasma total cholesterol level and lipid peroxidation in the plasma, as reflected by thiobarbituric acid-reactive substances (TBARS). This concentration of probucol did not lower plasma cholesterol, but markedly reduced TBARS in the plasma of cholesterol-fed rabbits. Aortic segments from cholesterol-fed rabbits produced 1.8-fold more .O2- (assessed by lucigenin-enhanced chemiluminescence) and decreased endothelium-dependent vascular relaxations to acetylcholine compared to vessels from normal rabbits. In cholesterol-fed rabbits, probucol treatment normalized both .O2- production and endothelium-dependent relaxations to acetylcholine. In control rabbits, probucol had no effect on either of these parameters. We conclude that probucol treatment may prevent .O2(-)-induced inactivation of endothelium-derived nitric oxide and reduce vascular oxidant stress via reducing the level of .O2-.

MeSH Terms (12)

Animals Anticholesteremic Agents Body Weight Cholesterol, Dietary Endothelium, Vascular Hypercholesterolemia Lipid Peroxidation Lipids Probucol Rabbits Superoxides Vasodilation

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