Barja G, Cadenas S, Rojas C, Pérez-Campo R, López-Torres M, Prat J, Pamplona R
Department of Animal Biology II (Animal Physiology), Faculty of Biology, Complutense University, Madrid, Spain.
Lipids. 1996 Sep;31(9):963-70. doi: 10.1007/BF02522690.
Guinea pigs were fed for five weeks with three diets containing different levels of vitamin E: LOW (but nondeficient, 15 mg of vitamin E/kg diet), MEDIUM (150 mg/kg diet), and HIGH (1,500 mg/kg diet). Dietary vitamin E supplementation did not change oxidative stress indicators in the hydrophilic compartment but increased liver alpha-tocopherol in a dose-dependent way and strongly decreased sensitivity to nonenzymatic in vitro liver lipid peroxidation. This last effect was already observed in group MEDIUM, and no further decrease in in vitro lipid peroxidation occurred from group MEDIUM to group HIGH. The protective effect of vitamin E against in vitro lipid peroxidation was observed even though an optimum dietary concentration of vitamin C for this animal model was present in the three different vitamin E diets. Both HIGH and LOW vitamin E decreased percentage fatty acid unsaturation in all phospholipid fractions from membrane origin in relation to group MEDIUM. The results, together with previous information, show that both vitamin E and vitamin C at intermediate concentrations are needed for optimal protection against lipid peroxidation and loss of fatty acid unsaturation even in normal nonstressful conditions. These protective concentrations are higher than those needed to avoid deficiency syndromes.
给豚鼠喂食三种含有不同水平维生素E的日粮，为期五周：低剂量组（但不缺乏，日粮中维生素E含量为15毫克/千克）、中剂量组（日粮中维生素E含量为150毫克/千克）和高剂量组（日粮中维生素E含量为1500毫克/千克）。日粮中补充维生素E并未改变亲水区的氧化应激指标，但肝脏α-生育酚以剂量依赖的方式增加，并且对体外肝脏非酶脂质过氧化的敏感性显著降低。在中剂量组就已观察到最后这种效应，从中剂量组到高剂量组，体外脂质过氧化没有进一步降低。尽管在三种不同维生素E日粮中都存在该动物模型的最佳日粮维生素C浓度，但仍观察到维生素E对体外脂质过氧化的保护作用。相对于中剂量组，高剂量组和低剂量组的维生素E均降低了膜来源的所有磷脂组分中脂肪酸不饱和度的百分比。这些结果与先前的信息一起表明，即使在正常无应激条件下，中等浓度的维生素E和维生素C对于最佳保护免受脂质过氧化和脂肪酸不饱和度损失都是必需的。这些保护浓度高于避免缺乏综合征所需的浓度。
