Chung S M, Lee J Y, Lee M Y, Bae O N, Chung J H
College of Pharmacy, Seoul National University, Korea.
J Toxicol Environ Health A. 2001 Aug 24;63(8):617-29. doi: 10.1080/152873901316857798.
Previous studies demonstrated that menadione, a representative quinone compound, reacts nonenzymatically with thiols in plasma, resulting in the generation of reactive oxygen species and potentiation of menadione-induced platelet damage. Because of the reported association of menadione with hemolytic anemia in vivo, investigations were undertaken to identify the free radicals generated from the interaction of menadione with plasma, and to assess the potential role of plasma-generated free-radical species in menadione-dependent erythrocyte toxicity. In rat plasma, menadione increased the rate of oxygen consumption and both luminol- and lucigenin-amplified chemiluminescence in a concentration-dependent manner. Superoxide dismutase (SOD) inhibited lucigenin-amplified chemiluminescence, suggesting formation of superoxide anion. Menadione also induced significant increases in chemiluminescence when erythrocytes were suspended in plasma, but not when cells were suspended in buffer. Consistent with these findings, menadione-dependent hemolysis of erythrocytes occurred only when the cells were suspended in plasma. Various free-radical inhibitors were tested for their ability to inhibit menadione-induced hemolysis. Catalase and mannitol each produced significant inhibition, including an additive effect when both compounds were present, while SOD had no marked effect. In addition, pretreatment with 3-amino-1,2,4-triazole, an intracellular catalase inhibitor, potentiated menadione-induced cytotoxicity in the presence of plasma. These results suggest that both hydrogen peroxide and hydroxyl radicals are involved in menadione-mediated plasma erythrocyte cytotoxicity; however, superoxide anion does not appear to play a direct role.
先前的研究表明，甲萘醌作为一种典型的醌类化合物，可在血浆中与硫醇发生非酶反应，导致活性氧的生成以及甲萘醌诱导的血小板损伤增强。鉴于甲萘醌在体内与溶血性贫血的报道关联，开展了相关研究以鉴定甲萘醌与血浆相互作用产生的自由基，并评估血浆产生的自由基在甲萘醌依赖性红细胞毒性中的潜在作用。在大鼠血浆中，甲萘醌以浓度依赖性方式增加耗氧率以及鲁米诺和光泽精增强的化学发光。超氧化物歧化酶（SOD）抑制光泽精增强的化学发光，提示超氧阴离子的形成。当红细胞悬浮于血浆中时，甲萘醌也会显著增加化学发光，但当细胞悬浮于缓冲液中时则不会。与这些发现一致，仅当细胞悬浮于血浆中时才会发生甲萘醌依赖性红细胞溶血。测试了各种自由基抑制剂抑制甲萘醌诱导溶血的能力。过氧化氢酶和甘露醇均产生显著抑制作用，当两种化合物同时存在时具有相加效应，而SOD没有明显作用。此外，用细胞内过氧化氢酶抑制剂3-氨基-1,2,4-三唑预处理，在有血浆存在的情况下增强了甲萘醌诱导的细胞毒性。这些结果表明，过氧化氢和羟基自由基均参与甲萘醌介导的血浆红细胞细胞毒性；然而，超氧阴离子似乎并未发挥直接作用。
