Tadolini B, Cabrini L, Menna C, Pinna G G, Hakim G
Istituto di Chimica Biologica, Università di Sassari, Italy.
Free Radic Res. 1997 Dec;27(6):563-76. doi: 10.3109/10715769709097860.
In an experimental system where both Fe2+ autoxidation and generation of reactive oxygen species is negligible, the effect of FeCl2 and FeCl3 on the peroxidation of phosphatidylcholine (PC) liposomes containing different amounts of lipid hydroperoxides (LOOH) was studied; Fe2+ oxidation, oxygen consumption and oxidation index of the liposomes were measured. No peroxidation was observed at variable FeCl2/FeCl3 ratio when PC liposomes deprived of LOOH by triphenylphosphine treatment were utilized. By contrast, LOOH containing liposomes were peroxidized by FeCl2. The FeCl2 concentration at which Fe2+ oxidation was maximal, defined as critical Fe2+ concentration [Fe2+], depended on the LOOH concentration and not on the amount of PC liposomes in the assay. The LOOH-dependent lipid peroxidation was stimulated by FeCl3 addition; the oxidized form of the metal increased the average length of radical chains, shifted to higher values the [Fe2+] and shortened the latent period. The iron chelator KSCN exerted effects opposite to those exerted by FeCl3 addition. The experimental data obtained indicate the kinetics of LOOH-dependent lipid peroxidation depends on the Fe2+/Fe3+ ratio at each moment during the time course of lipid peroxidation. The results confirm that exogenously added FeCl3 does not affect the LOOH-independent but the LOOH-dependent lipid peroxidation; and suggest that the Fe3+ endogenously generated exerts a major role in the control of the LOOH-dependent lipid peroxidation.
在一个亚铁离子（Fe2+）自氧化和活性氧生成均可忽略不计的实验系统中，研究了氯化亚铁（FeCl2）和氯化铁（FeCl3）对含有不同量脂质氢过氧化物（LOOH）的磷脂酰胆碱（PC）脂质体过氧化的影响；测定了脂质体的Fe2+氧化、耗氧量和氧化指数。当使用经三苯基膦处理去除LOOH的PC脂质体时，在不同的FeCl2/FeCl3比例下均未观察到过氧化现象。相比之下，含有LOOH的脂质体被FeCl2过氧化。将Fe2+氧化达到最大值时的FeCl2浓度定义为临界Fe2+浓度[Fe2+]*，它取决于LOOH浓度，而不取决于测定中PC脂质体的量。添加FeCl3可刺激依赖LOOH的脂质过氧化；金属的氧化形式增加了自由基链的平均长度，使[Fe2+]*向更高值移动并缩短了潜伏期。铁螯合剂硫氰酸钾（KSCN）产生的作用与添加FeCl3产生的作用相反。获得的实验数据表明，依赖LOOH的脂质过氧化动力学在脂质过氧化过程中的每个时刻都取决于Fe2+/Fe3+比例。结果证实，外源添加的FeCl3不影响不依赖LOOH的脂质过氧化，但影响依赖LOOH的脂质过氧化；并表明内源性生成的Fe3+在控制依赖LOOH的脂质过氧化中起主要作用。
