Singh K, Chander R, Kapoor N K
Division of Biochemistry, Central Drug Research Institute, Lucknow, India.
Indian J Biochem Biophys. 1997 Jun;34(3):313-8.
It has been reported earlier that high density lipoprotein (HDL) is a scavenger of superoxide anions, hydroxyl radicals (OH-) and behaves like superoxide dismutase. In the present investigation, we have studied the effect of HDL subclasses: HDL2 and HDL3 on non enzymatically induced oxidation of low density lipoprotein (LDL) by Fe2+ and sodium ascorbate. Both HDL2 and HDL3 showed protection against the oxidative degradation of LDL-lipids, measured as thiobarbituric acid reactive substance, lipid hydroperoxide and conjugated diene. Oxidized LDL was more electronegative, as evidenced by the increase in relative electrophoretic mobility(REM) on agarose gel. HDL3 significantly protected LDL apoprotein as assessed by reversal of REM after oxidation. HDL2 and HDL3 significantly inhibited the generation of OH- in nonenzymic systems in vitro. However, HDL2 was more active against enzymic formation of OH- as compared to HDL3. Alpha-tocopherol could protect LDL lipids and apoprotein components by Fe2+ mediated oxidation but the effects were lower than HDL subclasses. Our findings suggest that HDL subclasses, the potent scavenger of oxygen derived free radicals, play an important role to prevent the oxidative modifications in LDL.
早前有报道称，高密度脂蛋白（HDL）是超氧阴离子、羟基自由基（OH-）的清除剂，其作用类似于超氧化物歧化酶。在本研究中，我们研究了HDL亚类HDL2和HDL3对Fe2+和抗坏血酸钠非酶诱导的低密度脂蛋白（LDL）氧化的影响。HDL2和HDL3均对LDL脂质的氧化降解具有保护作用，以硫代巴比妥酸反应物质、脂质氢过氧化物和共轭二烯来衡量。氧化型LDL的负电性更强，这在琼脂糖凝胶上相对电泳迁移率（REM）的增加中得到证实。通过氧化后REM的逆转评估，HDL3对LDL载脂蛋白具有显著的保护作用。HDL2和HDL3在体外非酶体系中显著抑制OH-的产生。然而，与HDL3相比，HDL2对酶促形成OH-的活性更高。α-生育酚可以保护LDL脂质和载脂蛋白成分免受Fe2+介导的氧化，但效果低于HDL亚类。我们的研究结果表明，HDL亚类作为氧衍生自由基的有效清除剂，在预防LDL的氧化修饰中发挥着重要作用。
