Dwight J F, Hendry B M
Department of Cardiology, Southmead Hospital, Bristol, UK.
Clin Chim Acta. 1996 May 30;249(1-2):167-81. doi: 10.1016/0009-8981(96)06286-9.
The oxidising actions of tert-butyl hydroperoxide (tBH) (0-3 mmol/l) on human erythrocyte membrane ion transport have been studied using measurements of 86Rb+ influx. Ouabain and bumetanide were used to distinguish Rb+ flux via the sodium pump (Na,K-ATPase), Na,K,2Cl cotransporter and through residual membrane permeability. The protective actions of antioxidants and related molecules (vitamin E, vitamin E acetate, Trolox, butylated hydroxytoluene (BHT) and dithioerythritol (DTE) were studied. The effects of tBH were concentration dependent and the mean residual (ouabain and bumetanide insensitive) Rb+ permeability was increased by a factor of 8.5 (S.E.M. 2.2, n = 15) by a 5-min exposure to 2 mmol/l tBH. This action was almost completely prevented by co-incubation with Trolox or BHT, and partially prevented by the presence of vitamin E or DTE. Incubation with 2 mmol/l tBH for 5 min increased intracellular Na+ by a factor of 1.8 (S.E.M. 0.1, n = 8) and reduced intracellular K+ by a factor of 0.93 (S.E.M. 0.03, n = 8). These effects were prevented by Trolox and partially prevented by vitamin E, whereas DTE and vitamin E acetate were ineffective. Incubation with 2 mmol/l tBH for 5 min reduced the mean apparent sodium pump Vmax by 43% (S.E.M. 4, n = 8). This effect was completely prevented by Trolox and partially prevented by vitamin E. Vitamin E acetate had no effect. The mean bumetanide-sensitive Rb+ influx via the Na,K,2Cl cotransporter was reduced by 30% (S.E.M. 8.7, n = 25) by a 5-min exposure to 2 mmol/l tBH. This action was variable and no significant actions of the antioxidants studied could be demonstrated. This study suggests that tBH-mediated oxidative damage occurs from a hydrophilic site and involves increased non-selective membrane cation permeability and inhibition of specific transport systems.
通过测量⁸⁶Rb⁺流入量，研究了叔丁基过氧化氢（tBH）（0 - 3 mmol/L）对人红细胞膜离子转运的氧化作用。使用哇巴因和布美他尼来区分通过钠泵（Na，K - ATP酶）、Na，K，2Cl协同转运体以及残余膜通透性的Rb⁺通量。研究了抗氧化剂及相关分子（维生素E、维生素E醋酸酯、Trolox、丁基羟基甲苯（BHT）和二硫赤藓糖醇（DTE））的保护作用。tBH的作用呈浓度依赖性，在2 mmol/L tBH中暴露5分钟，平均残余（对哇巴因和布美他尼不敏感）Rb⁺通透性增加了8.5倍（标准误2.2，n = 15）。与Trolox或BHT共同孵育几乎完全阻止了这种作用，维生素E或DTE的存在部分阻止了这种作用。在2 mmol/L tBH中孵育5分钟，细胞内Na⁺增加了1.8倍（标准误0.1，n = 8），细胞内K⁺减少了0.93倍（标准误0.03，n = 8）。Trolox阻止了这些作用，维生素E部分阻止了这些作用，而DTE和维生素E醋酸酯无效。在2 mmol/L tBH中孵育5分钟，平均表观钠泵Vmax降低了43%（标准误4，n = 8）。这种作用被Trolox完全阻止，被维生素E部分阻止。维生素E醋酸酯没有作用。在2 mmol/L tBH中暴露5分钟，通过Na，K，2Cl协同转运体的平均布美他尼敏感的Rb⁺流入量减少了30%（标准误8.7，n = 25）。这种作用是可变的，所研究的抗氧化剂没有显示出显著作用。这项研究表明，tBH介导的氧化损伤发生于一个亲水位点，涉及非选择性膜阳离子通透性增加和特定转运系统的抑制。
