Mm. Mahfouz et al., EFFECT OF CHOLESTEROL-RICH DIETS WITH AND WITHOUT ADDED VITAMIN-E ANDVITAMIN-C ON THE SEVERITY OF ATHEROSCLEROSIS IN RABBITS, The American journal of clinical nutrition, 66(5), 1997, pp. 1240-1249
Oxysterols as oxidation products of cholesterol are considered an athe
rogenic factor in the development of atherosclerosis in the arteries o
f cholesterol-fed rabbits. We compared the atherogenic effects of diet
s enriched either with 0.5% oxidized cholesterol (OC; characterized by
high amounts of oxysterols) or with pure cholesterol (PC). The effect
s of antioxidant vitamins E and C added to the PC diet were also evalu
ated in view of their antioxidative properties for lipoproteins and ch
olesterol and how this could affect the severity of atherosclerosis. F
our groups of rabbits were fed the following for 11 wk: 1) a nonpurifi
ed stock diet, 2) this stock diet plus 0.5% OC, 3) the stock diet plus
0.5% PC, and 4) the stock diet plus 0.5% PC and 1000 mg vitamin E and
500 mg vitamin C/kg diet (PC + antioxidants). The OC and PC diets wer
e equally hyperlipidemic and hypercholesterolemic. The severity of ath
erosclerotic lesions was highest with the OC diet and lowest with the
PC + antioxidants diet. The plasma oxysterol concentration was proport
ional to the severity of atherosclerosis in all three groups of choles
terol-fed rabbits. beta-Very-low-density-lipoprotein modification was
minimized by vitamins E and C as indicated by its polyacrylamide gel e
lectrophoretic pattern and its increased binding to the rabbit liver m
embrane in vitro. This study indicated that OC and PC were equally ath
erogenic but that the addition of antioxidants to the PC diet signific
antly reduced its severity, even when hypercholesterolemia persisted.
This indicated that atherogenesis can result from an excessive accumul
ation of oxidation products of cholesterol in the plasma.