低密度脂蛋白体外氧化修饰过程中几种产物变化的动力学研究

Studies on Kinetic Changes of Several Products Produced During Oxidative Modification of Low Density Lipoprotein in vitro

用Ｃｕ￣（２＋）引发低密度脂蛋白的氧化修饰，研究了低密度脂蛋白氧化修饰过程中脂氢过无化物、共轭二烯烃、硫代巴比妥酸反应物质、琼脂糖凝胶电泳迁移率和荧光物质含量变化的动力学。结果发现：硫代巴比妥酸反应物质、琼脂糖凝胶电泳迁移率和荧光物质含量随修饰时间的延长呈增加趋势，它们含量的高低可以反映低密度脂蛋白的修饰程度。而脂氢过氧化物和共轭二烯烃的变化则不同，它们的动力学变化呈现三个时相：延迟期、扩增期和降解期，它们的高低不能反应低密度脂蛋白的修饰程度，但可通过观察延迟期的时间长短，研究不同来源低密度脂蛋白氧化修饰的难易程度及抗氧化剂对低密度脂蛋白氧化修饰的抑制作用。

Aim Oxidative modification of low density lipoprotein(LDL)has been proved to play a crucial.role in atherogenesis,In this paper,we studied the kinetic changes of several products produced during oxidative modification of LDL in vitro. Methods Oxidative modification of LDL was initiated by Cu2+ and kinetic changes of lipid hydroperoxides(LOOH),conjugated diene(CD),thiobarbrturic acid reactive substances(TBARS),relative electrophoretic mobility(REM) and fluorescence of LDL were determined. Results The content of TBARS,fluorescence in LDL and REM of LDL increased with the modification time,but the changes of LOOH and CD were different.Their kinetic changes showed three different phases:lag, propagation and decomposition. Conclusions The values of TBARS,REM and fluorescence of LDL could denote the extent of modification,but that of LOOH and CD cold not.By comparing the lag time,the susceptibility to the oxidative modification of LDL from different donors and the inhibitory effect of antioxidants on the oxidative modification could be studied.