Arrio B, Bonnefont-Rousselot D, Catudioc J D, Packer L
Laboratoire Membranaire Bioénergétique, Université de Paris-Sud, Orsay, France.
Biochem Mol Biol Int. 1993 Aug;30(6):1101-14.
Laser Doppler Electrophoresis was used to detect changes in the surface charge of low density lipoprotein populations exposed to oxidative stress. Before oxidative stress, low density lipoprotein suspensions exhibited homogenous populations of net negative charge but after exposure to hydroxyl and superoxide radicals, peroxyl radicals, or by Cu2+ generated oxidants they exhibited Laser Doppler Electrophoresis changes. The major population of low density lipoprotein became more negatively charged, in agreement with agarose gel electrophoresis. However, Laser Doppler Electrophoresis detected greater heterogeneity of low density lipoprotein, compared to agarose gel electrophoresis. Partially oxidized low density lipoprotein exhibited a less negatively charged subpopulation of particles compared to control samples. This has not been reported previously. Hence, Laser Doppler Electrophoresis is a sensitive method for detecting the appearance of subpopulations of differing surface charge density in oxidatively modified low density lipoprotein. beta-carotene protected low density lipoprotein against oxidative modification even when endogenous vitamin E levels are low. Vitamin E-deficient low density lipoprotein pretreated with beta-carotene exhibited a more narrow negative population when oxidized with peroxyl radicals, compared to control. Native low density lipoprotein pretreated with a mixture of all-trans- and cis-beta-carotene was also protected.
激光多普勒电泳用于检测暴露于氧化应激下的低密度脂蛋白群体表面电荷的变化。在氧化应激之前，低密度脂蛋白悬浮液呈现出净负电荷的均匀群体，但在暴露于羟基和超氧自由基、过氧自由基或由Cu2+产生的氧化剂后，它们呈现出激光多普勒电泳变化。与琼脂糖凝胶电泳一致，低密度脂蛋白的主要群体带负电荷更多。然而，与琼脂糖凝胶电泳相比，激光多普勒电泳检测到低密度脂蛋白的异质性更高。与对照样品相比，部分氧化的低密度脂蛋白表现出带负电荷较少的颗粒亚群。这以前尚未见报道。因此，激光多普勒电泳是检测氧化修饰的低密度脂蛋白中不同表面电荷密度亚群出现的一种灵敏方法。即使内源性维生素E水平较低，β-胡萝卜素也能保护低密度脂蛋白免受氧化修饰。与对照相比，用β-胡萝卜素预处理的维生素E缺乏的低密度脂蛋白在用过氧自由基氧化时表现出更窄的负电荷群体。用全反式和顺式β-胡萝卜素混合物预处理的天然低密度脂蛋白也受到了保护。
