Dietary vitamin E increases the resistance to lipoprotein oxidation and attenuates endothelial dysfunction in the cholesterol-fed rabbit.
This study was conducted to determine if vitamin E could reverse or attenuate endothelial dysfunction following an atherogenic diet. Rabbits were initially fed 1% cholesterol for 4 weeks to induce endothelial dysfunction. During the next 4 weeks the rabbits were fed either 1% cholesterol +0.2% vitamin E or 1% cholesterol alone, and were then killed. Endothelium-dependent responses to acetylcholine, calcium ionophore A23187 and sodium nitroprusside (SNP) were studied in the preconstricted perfused rabbit ear. Dietary vitamin E partially reversed the impaired endothelium-dependent responses to acetylcholine associated with cholesterol feeding. The maximum decrease in perfusion pressure in response to acetylcholine was 77.8% +/- 3.6% in control animals, 35.3% +/- 2.6% in cholesterol-fed animals, and 49.1% +/- 4.7% in cholesterol+vitamin E treated animals. The response to A23187 or sodium nitroprusside did not differ between the groups. The susceptibility of rabbit beta-VLDL to oxidation was markedly decreased in the vitamin E treated animals as assessed by the formation of conjugated dienes. The formation of lipid peroxidation products were also significantly inhibited by vitamin E. These data suggest that dietary vitamin E is beneficial in reducing the oxidative injury that may lead to the impairment of nitric oxide (NO)-mediated responses in early hypercholesterolaemia.
William Harvey Research Institute, St. Bartholomew's Hospital Medical College, London, UK.
J
J
Matz
T L
TL
Andersson
G A
GA
Ferns
E E
EE
Anggård
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002784:Cholesterol / Q000097:blood; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology*; D015227:Lipid Peroxidation; D008079:Lipoproteins, VLDL / Q000378:metabolism*; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D011817:Rabbits; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014810:Vitamin E / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology
D002791:Cholesterol, Dietary; D008079:Lipoproteins, VLDL; D014810:Vitamin E; D009599:Nitroprusside; D000001:Calcimycin; D002784:Cholesterol; D000109:Acetylcholine