Berson Alain, Cazanave Sophie, Descatoire Véronique, Tinel Marina, Grodet Alain, Wolf Claude, Feldmann Gérard, Pessayre Dominique
Institut National de la Santé et de la Recherche Médicale U773, Equipe Mitochondries, Faculté de Médecine Xavier Bichat, BP 416, 16 rue Henri Huchard, F-75018, Université Paris, France.
J Pharmacol Exp Ther. 2006 Jul;318(1):444-54. doi: 10.1124/jpet.106.104125. Epub 2006 Apr 14.
Like other nonsteroidal anti-inflammatory drugs, nimesulide (4-nitro-2-phenoxymethane-sulfoanilide) triggers hepatitis in a few recipients. Although nimesulide has been shown to uncouple mitochondrial respiration and cause hepatocyte necrosis in the absence of albumin, mechanisms for cell death are incompletely understood, and comparisons with human concentrations are difficult because 99% of nimesulide is albumin-bound. We studied the effects of nimesulide, with or without a physiological concentration of albumin, in isolated rat liver mitochondria or microsomes and in human hepatoma cells. Nimesulide did not undergo monoelectronic nitro reduction in microsomes. In mitochondria incubated without albumin, nimesulide (50 microM) decreased the mitochondrial membrane potential (DeltaPsim), increased basal respiration, and potentiated the mitochondrial permeability transition (MPT) triggered by calcium preloading. In HUH-7 cells incubated for 24 h without albumin, nimesulide (1 mM) decreased the DeltaPsim and cell NADPH and increased the glutathione disulfide/reduced glutathione ratio and cell peroxides; nimesulide triggered MPT, ATP depletion, high cell calcium, and caused mostly necrosis, with rare apoptotic cells. Coincubation with either cyclosporin A (an MPT inhibitor) or the combination of fructose-1,6-diphosphate (a glycolysis substrate) and oligomycin (an ATPase inhibitor) prevented the decrease in DeltaPsim, ATP depletion, and cell death. A physiological concentration of albumin abolished the effects of nimesulide on isolated mitochondria or HUH-7 cells. In conclusion, the weak acid, nimesulide, uncouples mitochondria and triggers MPT and ATP depletion in isolated mitochondria or hepatoma cells incubated without albumin. However, in the presence of albumin, only a fraction of the drug enters cells or organelles, and uncoupling and toxicity are not observed.
与其他非甾体抗炎药一样，尼美舒利（4-硝基-2-苯氧基甲烷磺酰苯胺）会在少数使用者中引发肝炎。尽管已表明尼美舒利在无白蛋白的情况下会解偶联线粒体呼吸并导致肝细胞坏死，但细胞死亡机制尚未完全明确，且由于99%的尼美舒利与白蛋白结合，因此难以与人体浓度进行比较。我们研究了尼美舒利在有无生理浓度白蛋白的情况下，对分离的大鼠肝线粒体或微粒体以及人肝癌细胞的影响。尼美舒利在微粒体中未发生单电子硝基还原。在无白蛋白孵育的线粒体中，尼美舒利（50微摩尔）降低了线粒体膜电位（ΔΨm），增加了基础呼吸，并增强了由钙预加载引发的线粒体通透性转换（MPT）。在无白蛋白孵育24小时的HUH-7细胞中，尼美舒利（1毫摩尔）降低了ΔΨm和细胞NADPH，并增加了谷胱甘肽二硫化物/还原型谷胱甘肽比值以及细胞过氧化物；尼美舒利引发了MPT、ATP耗竭、细胞内高钙，并主要导致坏死，凋亡细胞罕见。与环孢素A（一种MPT抑制剂）或果糖-1,6-二磷酸（一种糖酵解底物）与寡霉素（一种ATP酶抑制剂）的组合共同孵育可防止ΔΨm降低、ATP耗竭和细胞死亡。生理浓度的白蛋白消除了尼美舒利对分离线粒体或HUH-7细胞的影响。总之，弱酸尼美舒利在无白蛋白孵育的分离线粒体或肝癌细胞中会解偶联线粒体并引发MPT和ATP耗竭。然而，在有白蛋白存在的情况下，只有一小部分药物进入细胞或细胞器，未观察到解偶联和毒性作用。
