Minigh Jennifer L, Valentovic Monica A
Department of Pharmacology, Joan C. Edward School of Medicine, Marshall University, Huntington, WV 25704-9388, USA.
Toxicology. 2003 Mar 3;184(2-3):113-23. doi: 10.1016/s0300-483x(02)00554-1.
Rhabdomyolysis is associated with acute renal failure. The following study first characterized myoglobin in vitro toxicity using renal cortical slices isolated from male Fischer 344 rats. This model provided interaction between various cells within the nephron and provides myoglobin access predominantly through the basolateral membrane. Second, this study examined the effect of deferoxamine (DFX) and glutathione on myoglobin toxicity to determine the role of radicals and iron. Renal cortical slices were incubated for 30-120 min with 0, 4, 10 or 12 mg/ml myoglobin. Myoglobin was pretreated with 4 mM ascorbic acid prior to addition to the slices to ensure that myoglobin was in its reduced state. In other experiments tissues were pretreated for 15 min with 0.1 mM of the iron chelator DFX or 30 min with 1 mM glutathione prior to co-incubation with myoglobin. Finally, slices were pretreated with 1 mM glutathione for 30 min, rinsed and incubated only with myoglobin. Early event changes occurred within a 60 min exposure and included a decline in pyruvate-stimulated gluconeogenesis, increased lipid peroxidation levels and decreased glutathione levels. Loss of ATP levels and increased lactate dehydrogenase (LDH) release required a 120 min exposure to myoglobin. DFX reduced myoglobin induced effects on LDH leakage but had no effect on gluconeogenesis suggesting that myoglobin toxicity had an iron dependent (LDH) and independent (gluconeogenesis) pathway. Pretreatment with glutathione provided complete protection and was mediated by intracellular events.
横纹肌溶解症与急性肾衰竭有关。以下研究首先使用从雄性Fischer 344大鼠分离的肾皮质切片对肌红蛋白的体外毒性进行了表征。该模型提供了肾单位内各种细胞之间的相互作用，并主要通过基底外侧膜使肌红蛋白得以进入。其次，本研究考察了去铁胺（DFX）和谷胱甘肽对肌红蛋白毒性的影响，以确定自由基和铁的作用。将肾皮质切片与0、4、10或12mg/ml的肌红蛋白一起孵育30 - 120分钟。在添加到切片之前，肌红蛋白先用4mM抗坏血酸进行预处理，以确保肌红蛋白处于还原状态。在其他实验中，组织在与肌红蛋白共同孵育之前，先用0.1mM的铁螯合剂DFX预处理15分钟，或用1mM谷胱甘肽预处理30分钟。最后，切片先用1mM谷胱甘肽预处理30分钟，冲洗后仅与肌红蛋白一起孵育。早期事件变化发生在60分钟的暴露时间内，包括丙酮酸刺激的糖异生减少、脂质过氧化水平增加和谷胱甘肽水平降低。ATP水平的丧失和乳酸脱氢酶（LDH）释放的增加需要120分钟的肌红蛋白暴露时间。DFX降低了肌红蛋白对LDH泄漏的诱导作用，但对糖异生没有影响，这表明肌红蛋白毒性具有铁依赖性（LDH）和非依赖性（糖异生）途径。谷胱甘肽预处理提供了完全的保护，并且是由细胞内事件介导的。
