几种抗氧化剂抑制低密度脂蛋白氧化修饰能力的比较研究

COMPARATIVE STUDIES OF INHIBITORY CAPACITY OF SEVERAL ANTIOXIDANTS ON THE OXIDATIVE MODIFICATION OF LOW DENSITY LIPOPROTEIN

用ＦＯＸ（Ｆｅｒｒｏｕｓｉｏｎｏｘｉｄａｔｉｏｎｉｎｐｒｅｓｅｎｃｅｏｆｆｅｒｒｉｃｉｏｎｉｎｄｉｃａｔｏｒｘｙｌｅｎｏｌｏｒａｎｇｅｆｏｒｍｅａｓｕｒｅｍｅｎｔｏｆｈｙｄｒｏｐｅｒｏｘｉｄｅｓ）法直接测定脂氢过氧化物（ＬＯＯＨ），观察了低密度脂蛋白（ＬＤＬ）氧化修饰过程中ＬＯＯＨ变化的动力学，研究了抗氧化剂ｐｒｏｂｕｃｏｌ、ＢＨＴ、ＶＥ、ＶＣ和β－胡萝卜素对ＬＤＬ氧化修饰的抑制作用，并比较了它们抑制能力的大小。结果显示：ＬＤＬ氧化修饰过程中ＬＯＯＨ的变化呈现三个时相：第一为延迟期，ＬＯＯＨ几乎没有变化；第二为扩增期，ＬＯＯＨ急剧增加；第三为降解期，ＬＯＯＨ达到最大值并开始出现下降趋势。抗氧化剂可以使延迟期的时间延长，延长的时间长短与抗氧化剂的浓度成正比。以ＶＥ或ＶＣ为标准，求出不同浓度各种抗氧化剂延长延迟期的时间及其相应的ＶＥ或ＶＣ浓度，计算出其浓度与相对的ＶＥ或ＶＣ间的倍数，通过比较倍数的大小，得出其抑制ＬＤＬ氧化修饰能力的大小顺序为：ＢＨＴ＞Ｐｒｏｂｕｃｏｌ＞ＶＥ＞ＶＣ＞β－胡萝卜素。

Kinetic changes of lipid hydroperoxides (LOOH) during oxidative modification of LDL induced by Cu2+ was observed and inhibitory capacity of antioxidants: probucol,BHT, VE, VC and β- carotenee was compared by direct determination of LOOH using FOX method. The results showed that the changes of LOOH during oxidative modification could be divided into three stages. At first, there was a lag stage during which LOOH did not change, then followed by a drastic increase (propagation stage).Finally, LOOH reached the maximum value and had a tendency to decrease (decomposition stage). The addition of antioxidants could prolong the lag time and the prolonged time was proportional to the concentration of VE or VC. The concentration of VE or VC equivalent to that of an antioxidant in the prolonged lag time could be determined and calculated. By comparing the equivalency, the sequence of the inhibitory capacity of antioxidants was as follows: BHT> probucol> VE> VC> β-carotene.