Ito Y, Suzuki Y, Ogonuki H, Hiraishi H, Razandi M, Terano A, Harada T, Ivey K J
Department of Medicine, Veterans Affairs Medical Center, Long Beach, California 90822.
Dig Dis Sci. 1994 Jun;39(6):1257-64. doi: 10.1007/BF02093791.
The aims of this study were to investigate the roles of iron as a catalyst in reactive oxygen metabolite-mediated cellular injury and of the endogenous antioxidant defenses against acetaminophen-induced cytotoxicity in cultured rat hepatocytes. Hepatocytes were isolated and cultured from either 3-methylcholanthrene-treated or untreated rats. Cytotoxicity was evaluated by measuring 51Cr and lactate dehydrogenase release. Acetaminophen caused dose-dependent cytotoxicity in 3-methylcholanthrene-treated, but not untreated, cells. There was a good correlation between 51Cr and lactate dehydrogenase release values. Pretreatment with both diethyl maleate, which covalently binds glutathione as catalyzed by glutathione-S-transferase, and bis(chloroethyl)-nitrosourea, an inhibitor of glutathione reductase, enhanced acetaminophen-induced cytotoxicity. Inhibition of endogenous catalase activity by pretreatment with aminotriazole did not affect acetaminophen-induced cellular damage. Addition of exogenous catalase failed to protect against acetaminophen-induced cytotoxicity. Preincubation with both deferoxamine, a ferric iron chelator, and phenanthroline, a ferrous iron chelator, diminished acetaminophen-induced cytotoxicity. These results indicate that iron is crucial in mediating acetaminophen-induced cytotoxicity and that the glutathione redox cycle, but not catalase, plays a critical role in the endogenous defenses against acetaminophen-induced cellular damage in cultured rat hepatocytes in vitro.
本研究的目的是探讨铁作为活性氧代谢物介导的细胞损伤的催化剂的作用，以及内源性抗氧化防御对培养的大鼠肝细胞中对乙酰氨基酚诱导的细胞毒性的作用。从经3-甲基胆蒽处理或未处理的大鼠中分离并培养肝细胞。通过测量51Cr和乳酸脱氢酶释放来评估细胞毒性。对乙酰氨基酚在经3-甲基胆蒽处理的细胞中引起剂量依赖性细胞毒性，但在未处理的细胞中则不然。51Cr和乳酸脱氢酶释放值之间存在良好的相关性。用马来酸二乙酯（由谷胱甘肽-S-转移酶催化共价结合谷胱甘肽）和谷胱甘肽还原酶抑制剂双（氯乙基）-亚硝基脲预处理均增强了对乙酰氨基酚诱导的细胞毒性。用氨基三唑预处理抑制内源性过氧化氢酶活性并不影响对乙酰氨基酚诱导的细胞损伤。添加外源性过氧化氢酶未能预防对乙酰氨基酚诱导的细胞毒性。用铁螯合剂去铁胺和亚铁螯合剂菲咯啉预孵育可降低对乙酰氨基酚诱导的细胞毒性。这些结果表明，铁在介导对乙酰氨基酚诱导的细胞毒性中起关键作用，并且谷胱甘肽氧化还原循环而非过氧化氢酶在体外培养的大鼠肝细胞中对乙酰氨基酚诱导的细胞损伤的内源性防御中起关键作用。
