Masaki N, Kyle M E, Farber J L
Department of Pathology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Arch Biochem Biophys. 1989 Mar;269(2):390-9. doi: 10.1016/0003-9861(89)90122-7.
The killing of cultured hepatocytes by tert-butyl hydroperoxide was dissociated from the changes both in glutathione metabolism and in intracellular calcium homeostasis that accompany the metabolism of this toxin. Deferoxamine, a ferric iron chelator, keto-methiolbutyric acid, a radical scavenger, and the antioxidants N,N'-diphenyl-p-phenylenediamine (DPPD) and catechol prevented the cell killing without effect on glutathione or calcium metabolism. Malondialdehyde, formed as a result of the peroxidation of cellular lipids, accumulated before any loss of viability. Prevention of the lipid peroxidation paralleled the prevention of cell killing. As much as 25 microM DPPD or 1 mM catechol did not prevent the iron-dependent, catalase-insensitive formation of tert-butyl alkoxyl radicals. Thus, DPPD and catechol do not detoxify a radical species that kills the cells and initiates lipid peroxidation as an epiphenomenon. Furthermore, lipid peroxidation cannot be dismissed as simply a consequence of the cell killing. It is concluded that low concentrations of tert-butyl hydroperoxide (less than 1.0 mM) lethally injure cultured hepatocytes by a mechanism that depends on the peroxidation of cellular lipids.
叔丁基过氧化氢对培养肝细胞的杀伤作用与谷胱甘肽代谢及细胞内钙稳态的变化无关，而这两种变化伴随该毒素的代谢过程。去铁胺（一种铁离子螯合剂）、酮甲硫丁酸（一种自由基清除剂）以及抗氧化剂N,N'-二苯基对苯二胺（DPPD）和儿茶酚可防止细胞被杀伤，且对谷胱甘肽或钙代谢无影响。细胞脂质过氧化形成的丙二醛在细胞活力丧失之前就开始积累。防止脂质过氧化与防止细胞杀伤情况相似。高达25微摩尔的DPPD或1毫摩尔的儿茶酚并不能阻止叔丁基烷氧基自由基的铁依赖性、过氧化氢酶不敏感的形成。因此，DPPD和儿茶酚并不能使导致细胞死亡并引发脂质过氧化这一附带现象的自由基失活。此外，脂质过氧化不能仅仅被视为细胞死亡的结果而不予考虑。得出的结论是，低浓度（低于1.0毫摩尔）的叔丁基过氧化氢通过一种依赖细胞脂质过氧化的机制对培养的肝细胞造成致命损伤。
