脂质过氧化对人红细胞膜脂流动性的影响

EFFECT OF LIPID PEROXIDATION ON FLUIDITY OF HUMAN ERYTHROCYTE MEMBRANE

研究枯稀过氧化氢/高铁血红素体系所产生的烷基过氧自由基对红细胞的损伤。测定了脂质过氧化的产物——丙二脂的生成,并证明阿魏酸钠对脂质过氧化的抑制。荧光偏振的结果指出,膜脂过氧化以后降低了膜脂的流动性。人红细胞用5DSA和16DSA标记并用ESR检测膜脂流动性,结果表明,序参数S几乎没有发生变化,旋转相关时间τ值的增加证明膜脂过氧化以后,疏水尾部的物理状态发生了改变。经脂质过氧化以后,红细胞膜中的不饱和脂防酸的减少,可能是降低膜脂流动性的原因之一。

We described the damage from free radicals produced by cumene hydro-peroxide/he mia system to erythrocyte membrane. The malonaldehyde-measured following lipid peroxidation indicated that the lipid peroxidation can be inhibited by sodium ferulate, a free radical scavenger.Following cumene hydroperoxide/he min peroxidation,we examined the effect of lipid peroxidation on erythrocyte membrane fluidity. The fluorescence polarization results showed that lipid peroxidation resulted in significant decrease of membrane fluidity. To characterize the alteration in membrane molecular dynamics caused by oxygen radical, human erythrocyte membranes were spin labeled with 5-doxyl-stearic acid and 16-doxyl-stearic acid respectively. and alterations in membrane fluidity were quantified by electron spin resonance spectrometry, The ESR results indicated that thh order parameter value measured with 5DSA incorporation remains almost unchanged, but with 16DSA, quite different from 5DSA, is shown by a significant decrease of membrane fluidity (increase Value). These findings indicated that lipid peroxidation leads to an alteration of transbilayer fluidity gradient. Erythrocyte membrane contains a large proportion of polyunsaturated fatty acids susceptible to lipid peroxidation, the loss of unsaturation in this region of the bilayer as a result of lipid peroxidation may account for the decreased fluidity.