Ibrahim W, Lee U S, Yeh C C, Szabo J, Bruckner G, Chow C K
Department of Nutrition and Food Science, University of Kentucky, Lexington, KY 40506-0054, USA.
J Nutr. 1997 Jul;127(7):1401-6. doi: 10.1093/jn/127.7.1401.
The purpose of this study was to determine the effects of dietary fat, vitamin E and iron on oxidative damage and antioxidant status. Male Swiss-Webster mice (1 mo old) were fed a basal vitamin E-deficient diet that contained either 8% fish oil + 2% corn oil or 10% lard with or without 1 g dl-alpha-tocopheryl acetate. The diets without vitamin E contained either 0.21 or 0.95 g ferric citrate/kg. Diets were fed for 4 wk/kg diet. Compared with the vitamin E-supplemented groups, mice fed diets without vitamin E (with or without supplemental iron) had significantly (P < 0.05) higher hepatic levels of thiobarbituric acid-reactive substances (TBARS), conjugated dienes and protein carbonyls when they were fed fish oil, but not lard. The levels of TBARS were further increased by iron supplementation in the mice fed fish oil. Significantly lower concentrations of alpha-tocopherol and higher glutathione (GSH) were found in the liver of mice fed fish oil and vitamin E than in those fed lard and vitamin E (P < 0.05). The activities of superoxide dismutase and glucose-6-phosphate dehydrogenase were lower in the fish oil-fed mice than in those fed lard (P < 0.05). The activities of Se-GSH peroxidase, non-Se-GSH peroxidase, catalase, and glutathione reductase were not altered by dietary fat or vitamin E/iron. The results obtained provide experimental evidence of the prooxidative effects of high dietary fish oil and iron, and suggest that vitamin E protects not only lipid-soluble compounds, but also water-soluble constituents, against oxidative damage. Further, dietary lipid plays a key role in determining cellular susceptibility to oxidative stress.
本研究的目的是确定膳食脂肪、维生素E和铁对氧化损伤及抗氧化状态的影响。将1月龄的雄性瑞士韦伯斯特小鼠喂食基础维生素E缺乏饮食，该饮食含有8%鱼油 + 2%玉米油或10%猪油，添加或不添加1 g dl-α-生育酚乙酸酯。不含维生素E的饮食每千克含有0.21或0.95 g柠檬酸铁。以4周/千克饮食的量喂食这些饮食。与补充维生素E的组相比，喂食不含维生素E（添加或不添加铁）饮食的小鼠在喂食鱼油时，其肝脏中硫代巴比妥酸反应性物质（TBARS）、共轭二烯和蛋白质羰基水平显著（P < 0.05）升高，但喂食猪油时未出现这种情况。在喂食鱼油的小鼠中，补充铁会使TBARS水平进一步升高。与喂食猪油和维生素E的小鼠相比，喂食鱼油和维生素E的小鼠肝脏中α-生育酚浓度显著降低，谷胱甘肽（GSH）浓度更高（P < 0.05）。喂食鱼油的小鼠中超氧化物歧化酶和葡萄糖-6-磷酸脱氢酶的活性低于喂食猪油的小鼠（P < 0.05）。硒谷胱甘肽过氧化物酶、非硒谷胱甘肽过氧化物酶、过氧化氢酶和谷胱甘肽还原酶的活性不受膳食脂肪或维生素E/铁的影响。所获得的结果为高膳食鱼油和铁的促氧化作用提供了实验证据，并表明维生素E不仅能保护脂溶性化合物，还能保护水溶性成分免受氧化损伤。此外，膳食脂质在决定细胞对氧化应激的易感性方面起关键作用。
