Wiseman S A, Van den Boom M A, De Fouw N J, Wassink M G, Op den Kamp J A, Tijburg L B
Unilever Research Laboratory, Vlaardingen, The Netherlands.
Free Radic Biol Med. 1995 Nov;19(5):617-26. doi: 10.1016/0891-5849(95)00078-c.
This study has investigated the effect of dietary vitamin E on markers of antioxidant status. Four groups of rabbits received diets containing 30 energy percent (en%) total fat (7.8 en% contributed by linoleic acid) for 12 weeks. D,1-alpha tocopheryl acetate was added to the diets to obtain a range of vitamin E concentrations (49, 114, 179, or 775 tocopherol equivalents per kg diet). Increased vitamin E concentrations were demonstrated in plasma lipoproteins and erythrocyte membranes following supplementation, and dietary effects on lipid peroxidation were investigated by (i) monitoring a fluorescent parinaric acid probe incorporated into erythrocyte membranes in vivo, (ii) determination of malondialdehyde and oxysterols in plasma, and (iii) investigation of the susceptibility of low density lipoprotein (LDL) to copper-induced conjugated diene formation in vitro. No effects of vitamin E were observed on parinaric acid oxidation in vivo or on the accumulation of lipid peroxidation products in plasma, but the resistance of LDL to oxidation in vitro increased significantly as vitamin E was supplemented to the diets. Our results demonstrate that under these dietary conditions (7.8 en% linoleic acid) increasing the vitamin E content of plasma and erythrocytes approximately two-fold does not reduce the level of lipid peroxidation in vivo, indicating sufficient antioxidant capacity on the lowest vitamin E diet. In contrast, LDL became more resistant to an extreme oxidative stress applied in vitro. The relevance of these assays to currently proposed mechanisms of atherosclerosis is discussed.
本研究调查了膳食维生素E对抗氧化状态标志物的影响。四组兔子接受了含30能量百分比（en%）总脂肪（其中7.8 en%由亚油酸提供）的日粮，持续12周。向日粮中添加D-α-生育酚醋酸酯，以获得一系列维生素E浓度（每千克日粮中生育酚当量为49、114、179或775）。补充后血浆脂蛋白和红细胞膜中的维生素E浓度升高，通过以下方式研究日粮对脂质过氧化的影响：（i）监测体内掺入红细胞膜的荧光十八碳四烯酸探针；（ii）测定血浆中的丙二醛和氧化甾醇；（iii）研究低密度脂蛋白（LDL）在体外对铜诱导的共轭二烯形成的敏感性。未观察到维生素E对体内十八碳四烯酸氧化或血浆中脂质过氧化产物积累的影响，但随着日粮中补充维生素E，LDL在体外的抗氧化能力显著增强。我们的结果表明，在这些膳食条件下（7.8 en%亚油酸），将血浆和红细胞中的维生素E含量提高约两倍并不会降低体内脂质过氧化水平，这表明最低维生素E日粮具有足够的抗氧化能力。相比之下，LDL对体外施加的极端氧化应激更具抵抗力。讨论了这些测定方法与当前提出的动脉粥样硬化机制的相关性。
