Iron, heme oxygenase, and glutathione: effects on myohemoglobinuric proximal tubular injury.
Iron, heme oxygenase, and glutathione: effects on myohemoglobinuric proximal tubular injury.
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DOI：
10.1038/ki.1995.457
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发表时间：
1995-11
影响因子：
19.6
通讯作者：
R. Zager;Kirstin M. Burkhart;Duane Scott Conrad;Gmur Dj
中科院分区：
文献类型：
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作者：
R. Zager;Kirstin M. Burkhart;Duane Scott Conrad;Gmur Dj
铁、血红素加氧酶和谷胱甘肽：对肌血红蛋白尿性近端肾小管损伤的影响。本研究使用新型模型系统评估了铁、血红素加氧酶 (HO)、羟自由基 (•OH) 和谷胱甘肽 (GSH) 对肌血红蛋白尿性近端肾小管损伤起始阶段的影响。通过注射甘油诱导大鼠横纹肌溶解，四小时后分离近端肾小管段（PTS）。在存在或不存在铁螯合剂（去铁胺；DFO）、·OH 清除剂、·OH 捕获剂（水杨酸盐；用于测量·OH 产生）、GSH 或过氧化氢酶的情况下，将它们孵育 0 至 90 分钟。在选定的实验中，在注射甘油时给予 H2O2 抑制剂（Sn 原卟啉），以评估 H2O2 对不断发展的损伤的急性影响。细胞死亡和脂质过氧化分别通过LDH 释放百分比和丙二醛(MDA) 生成百分比来量化。来自正常大鼠的 PTS 作为对照。甘油后 PTS 在孵育过程中表现出渐进的 LDH 释放 (47 ± 2%) 和 20 倍的 MDA 增量，而在正常 PTS 中仅观察到 11 ± 1% LDH 释放且没有 MDA 生成。 DFO 完全阻止了甘油引起的损伤的两个参数。尽管先前的体内数据表明 H2O 是一种细胞保护剂，但 H2O 抑制发挥了急性保护作用。 •OH 清除剂和过氧化氢酶均不能减轻甘油后损伤，后者与•OH 产生的减少而不是增加相关。 GSH 略微降低了 LDH 的释放，同时引起矛盾的三倍 MDA 增量。后者是铁依赖性的（被DFO阻断），在正常PTS中表达，并且可以通过等摩尔半胱氨酸复制。 GSH 增加了无细胞系统（外源磷脂酰胆碱）中铁依赖性脂质过氧化，表明 GSH 代谢为半胱氨酸并不是该反应的必要条件。结论：（1）螯合铁可以充分解释血红素蛋白引发的近端肾小管损伤； (2) H2O 可能是通过引起铁释放而导致这种损伤； (3)血红素引起的损伤似乎是由非·OH氧化中间体介导的； (4) GSH同时具有抗氧化和促氧化作用； (5) 即时通讯甘油注射，然后进行近端肾小管分离，代表了研究血红素蛋白细胞毒性的直接决定因素的一种新的且非常有用的模型。
Iron, heme oxygenase, and glutathione: Effects on myohemoglobinuric proximal tubular injury. This study assessed the impacts of iron, heme oxygenase (HO), hydroxyl radical (•OH), and glutathione (GSH) on the initiation phase of myohemoglobinuric proximal tubular injury using a novel model system. Rhabdomyolysis was induced in rats by glycerol injection and four hours later proximal tubular segments (PTS) were isolated. They were incubated for 0 to 90 minutes either in the presence or absence of an iron chelator (deferoxamine; DFO), •OH scavengers, an •OH trapping agent (salicylate; to gauge •OH production), GSH, or catalase. In selected experiments, an HO inhibitor (Sn protoporphyrin) was given at the time of glycerol injection to assess HO's acute effects on the evolving injury. Cell death and lipid peroxidation were quantified by % LDH release and malondialdehyde (MDA) generation, respectively. PTS from normal rats served as controls. Post-glycerol PTS manifested progressive LDH release (47 ± 2%) and 20-fold MDA increments during the incubations, whereas only 11 ± 1% LDH release and no MDA generation was observed in the normal PTS. DFO completely prevented both parameters of glycerol-induced injury. HO inhibition exerted an acute protective effect, despite previousin vivodata suggesting that HO is a cytoprotectant. Neither •OH scavengers nor catalase mitigated post-glycerol injury, the latter correlating with reduced, not increased, •OH production. GSH slightly decreased LDH release while causing a paradoxical threefold MDA increment. The latter was iron dependent (blocked by DFO), was expressed in normal PTS, and it could be reproduced by equimolar cysteine. That GSH increased iron-dependent lipid peroxidation in a cell free system (exogenous phosphatidylcholine) indicated that GSH metabolism to cysteine was not a requirement for this reaction. In conclusion: (1) chelatable iron can fully account for heme protein-triggered proximal tubular injury; (2) HO contributes to this injury, presumably by causing iron release; (3) the heme-induced injury appears to be mediated by non-•OH oxidizing intermediates; (4) GSH can exert both anti- and pro-oxidant effects; and (5) i.m. glycerol injection, followed by proximal tubular isolation, represents a new and highly useful model for studying direct determinants of heme protein cytotoxicity.