不同水平维生素E和β—胡萝卜素对Cu^2＋氧化修饰低密度脂蛋白的影响

研究不同浓度的维生素Ｅ（ＶＥ）和β－胡萝卜素（βＣ）对Ｃｕ＾２＋诱导的氧化修饰低密度脂蛋白（ＬＤＬ）作用的影响，通过测定硫代巴比妥酸反应物质（ＴＢＡＲＳ）、ＬＤＬ的电泳迁移率（Ｒｆ?以及荧光物质（Ｌｉｐｏｆｕｓｉｎ）扫描，反映ＬＤＬ的氧化修饰程度。结果表明：ＶＥ、βＣ均可减少ＴＢＡＲＳ的产生、减小ＬＤＬ的Ｒｆ，并且具有剂量－效应关系，随浓度增加，ＶＥ抑制作用加强而βＣ抑制作用减弱，而且ＶＥ对ＴＢＡ

Effects of alpha-tocopherol and beta-carotene on the oxidized low density lipoprotein induced by Cu2+]

The effects of different concentrations of alpha-tocopherol and beta-carotene on low density lipoprotein(LDL) oxidation were examined. LDL was oxidized by Cu2+ in a cell-free(10 mumol/L Cu2+ in PBS) system. The results showed that alpha-tocopherol and beta-carotene inhibited the oxidative modification of LDL in this system as evidenced by a concentration-dependent decrease in lipid peroxide(thiobarbituric-acid-reasting substances activity, TBARS) and the electrophoretic mobility of LDL. The effect of alpha-tocopherol on the generation of TBARS was stronger, while on the electrophoretic mobility was weaker than that of beta-carotene. Both alpha-tocopherol and beta-carotene slightly but not significantly reduced lipofusin. It suggested that the mechanisms were different. Thus, beta-carotene, as well as alpha-tocopherol, inhibit LDL oxidation and might play important roles in reducing the generation of oxidized LDL.