Miccadei S, Kyle M E, Gilfor D, Farber J L
Department of Pathology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Arch Biochem Biophys. 1988 Sep;265(2):311-20. doi: 10.1016/0003-9861(88)90133-6.
Cultured hepatocytes were exposed to two chemicals, dinitrofluorobenzene (DNFB) and diethyl maleate (DEM), that abruptly deplete cellular stores of glutathione. Upon the loss of GSH, lipid peroxidation was evidenced by an accumulation of malondialdehyde in the cultures followed by the death of the hepatocytes. Pretreatment of the hepatocytes with a ferric iron chelator, deferoxamine, or the addition of an antioxidant, N,N'-diphenyl-p-phenylenediamine (DPPD), to the culture medium prevented both the lipid peroxidation and the cell death produced by either DNFB or DEM. However, neither deferoxamine nor DPPD prevented the depletion of GSH caused by either agent. Inhibition of glutathione reductase by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) or inhibition of catalase by aminotriazole sensitized the hepatocytes to the cytotoxicity of DNFB. In a similar manner, pretreatment with BCNU potentiated the cell killing by DEM. DPPD and deferoxamine protected hepatocytes pretreated with BCNU and then exposed to DNFB or DEM. These data indicate that an abrupt depletion of GSH leads to lipid peroxidation and cell death in cultured hepatocytes. It is proposed that GSH depletion sensitizes the hepatocyte to its constitutive flux of partially reduced oxygen species. Such an oxidative stress is normally detoxified by GSH-dependent mechanisms. However, with GSH depletion these activated oxygen species are toxic as a result of the iron-dependent formation of a potent oxidizing species.
将培养的肝细胞暴露于两种化学物质，即二硝基氟苯（DNFB）和马来酸二乙酯（DEM），这两种物质会突然耗尽细胞内的谷胱甘肽储备。随着谷胱甘肽（GSH）的丧失，丙二醛在培养物中的积累证明了脂质过氧化，随后肝细胞死亡。用铁螯合剂去铁胺对肝细胞进行预处理，或将抗氧化剂N，N'-二苯基对苯二胺（DPPD）添加到培养基中，可防止由DNFB或DEM引起的脂质过氧化和细胞死亡。然而，去铁胺和DPPD均不能阻止任何一种试剂引起的GSH消耗。用1,3-双（2-氯乙基）-1-亚硝基脲（BCNU）抑制谷胱甘肽还原酶或用氨基三唑抑制过氧化氢酶会使肝细胞对DNFB的细胞毒性敏感。以类似的方式，用BCNU预处理可增强DEM对细胞的杀伤作用。DPPD和去铁胺可保护先用BCNU预处理然后暴露于DNFB或DEM的肝细胞。这些数据表明，GSH的突然耗尽会导致培养的肝细胞发生脂质过氧化和细胞死亡。有人提出，GSH耗竭会使肝细胞对其部分还原的氧物种的组成通量敏感。这种氧化应激通常通过依赖GSH的机制解毒。然而，随着GSH的耗尽，这些活性氧由于铁依赖的强氧化物种的形成而具有毒性。
