Metabolism of oxidative phospholipids in peroxidized human erythrocytes membranes

本项目的目的是研究不同种类的自由基过氧化生物膜中氧化磷脂的代谢，这些自由基包括AAPH产生的烷基自由基和黄质/黄质素氧化酶产生的羟基自由基。在与AAPH共同过氧化的红细胞膜中，有明显的CGP过氧化氢生成，在XO/XOD/Fe过氧化体系中没有明显的CGP过氧化氢生成，表明CGP氢过氧化氢在该体系中是不稳定的。在AAPH-过氧化红细胞膜中也检测到过氧化氢分解的次生产物--醛类CGP。AAPH主要将CGP氧化成过氧化氢和醛磷脂，硫代巴比妥酸反应物质(TBARS)的生成量相对较低。另一方面，XO/XOD/Fe的过氧化导致磷脂的潜在分解，消除了对照中的大量TBARS，生成了微量的氧化型磷脂。本研究表明，磷脂在生物膜中的过氧化过程与其结构和过氧化条件密切相关，并测定了幼年和老年大鼠不同组织中磷脂的氧化量。老年大鼠肝、脑、心、肾组织中的过氧化磷脂和醛类磷脂含量显著高于青年大鼠。本研究首次证实了氧化应激下生物样品中氧化磷脂的生成，尤其是醛类磷脂的生成。

The aim of this project was to examine the metabolism of oxidized phospholipids in biological membranes peroxidized with different kinds of radicals which were alkyl radical produced with AAPH and hydroxy radical with xanthin/xanthin oxidase. CGP hydroperoxide as a primary product of peroxidation significantly formed in RBC membrane peroxidized with AAPH.No consisitent generation of CGP hydroperoxide was evident in XO/XOD/Fe peroxidation, indicating that CGP hydroperoxide is instable in this system. Aldehydic CGP as a secondary product of hydroperoxide decomposition also detected in AAPH-peroxidized RBC membrane. AAPH mainly oxidized CGP to hydroperoxide and aldehydic phospholipids and the production of thiobarbityric acid-reactive substance (TBARS) was relatively low. On the other hand, XO/XOD/Fe peroxidation caused the potential decompositon of phospholipids to eliminate large amounts of TBARS in conrast to generate a trace amounts of oxidized phopholipids. The present study indicates that the process of peroxidation of phospholipids in biomembrane greatly depends on their strucure and the peroxidation condition.The amounts of oxidized phospholipids were also determined in various tissues of young and old rats. Phospholipid hydroperoxides and aldehydic phospholipids in liver, brain heart and kidney of old rats were significantly higher than those of young rats.The present studt demonstrated the productions of oxidazed phospholipids, especially aldehydic phospholipids in biological samples suffered with oxidative stress at the first time.