RELATIONSHIP OF FREE RADICALS TO HALOCARBON-INDUCED TOXICITY IN THE LIVER

自由基与卤代烃引起的肝脏毒性的关系

• 批准号: 3918692
• 负责人: R P MASON
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3918692
• 关键词: anesthetics; carbon dioxide; cell membrane; cytochrome P450; drug adverse effect; electron spin resonance spectroscopy; free radicals; hepatotoxin; ion transport; laboratory rat; lactate dehydrogenases; metyrapone; molecular biology; phenobarbital

CC14 has been shown previously to be metabolized to the trichloromethyl radical (.CC13) and to a novel oxygen-containing carbon dioxide anion radical (.C02-) in the perfused rat liver. These free radicals were detected by electron spin resonance using the spin-trapping technique. The .C02- radical adduct also was observed in urine following the intragastric administration of CC14 or CBrC13 and spin trap. Detection of the .C02- adduct in the effluent perfusate was decreased 3-4 fold by DIDS (0.2 mM), an inhibitor of the plasma membrane anion transport system. The rate of formation of .CO2- radical adduct was decreased 2-3 fold following inhibition of cytochrome P-450-dependent mono-oxygenases by metyrapone (0.5 mM) and was increased about two-fold by induction of cytochrome P-450 by phenobarbital pretreatment. Toxicity of halocarbons in the perfused liver was assessed by measuring the release of lactate dehydrogenase (LDH) into the effluent perfusate in livers from phenobarbital-treated rats under conditions identical to those employed to detect radical adducts (i.e., during the infusion of CC14 or CBrC13 into livers perfused with either nitrogen- or oxygen-saturated perfusate). Metabolism of halocarbons to .C02- radical adduct was 6-8 fold faster during perfusion with nitrogen-saturated rather than with oxygen-saturated perfusate. Concomitantly, liver damage detected from LDH release occurred much sooner during halocarbon infusion in the presence of nitrogen-saturated perfusate. A good correlation (r= -0.80) between the rate of formation of PBN/.C02- and the time to onset of LDH release following halocarbon infusion was observed. Therefore, it is concluded that PBN/.C02- is a useful marker for oxygen-containing free radical intermediates which may be causally related to halocarbon-induced hepatotoxicity. Recently, the .CC13 and .C02-radical adducts also have been detected in the bile from anesthetized rats.

CC14 先前已被证明可代谢为 三氯甲基自由基（.CC13）和新型含氧自由基 灌注大鼠肝脏中的二氧化碳阴离子自由基（.C02-）。 这些自由基通过电子自旋共振检测 自旋捕获技术。 .C02-自由基加合物也是 胃内给予 CC14 后尿液中观察到 或 CBrC13 和自旋陷阱。 检测.C02-加合物 DIDS (0.2 mM) 可将流出的灌注液减少 3-4 倍， 质膜阴离子转运系统抑制剂。 率 .CO2-自由基加合物的形成减少 2-3 倍 抑制细胞色素 P-450 依赖性单加氧酶后 甲吡酮 (0.5 mM) 增加约两倍 苯巴比妥预处理诱导细胞色素 P-450。 卤代烃在灌注肝脏中的毒性通过以下方法评估 测量乳酸脱氢酶（LDH）释放到 苯巴比妥治疗大鼠肝脏中的流出物灌注液 条件与检测自由基加合物所用的条件相同 （即，在将 CC14 或 CBrC13 输注到灌注的肝脏期间 与氮或氧饱和的灌注液）。 代谢 卤代烃转化为.C02-自由基加合物的速度加快了 6-8 倍 用氮饱和灌注而不是氧饱和灌注 灌注。 同时，LDH 释放检测到肝损伤 在卤化碳注入过程中，在存在以下物质的情况下，发生得更快： 氮饱和灌注液。 良好的相关性 (r= -0.80) PBN/.C02- 的形成速率与发病时间之间 观察到卤化碳输注后 LDH 释放的情况。 因此，得出结论：PBN/.C02- 是一个有用的标记 含氧自由基中间体可能是 与卤化碳引起的肝毒性有关。 最近，.CC13 胆汁中也检测到了.C02-自由基加合物 麻醉的老鼠。