Stäubli A, Boelsterli U A
Institute of Toxicology, Swiss Federal Institute of Technology, Schwerzenbach, Switzerland.
Am J Physiol. 1998 Jun;274(6):G1031-7. doi: 10.1152/ajpgi.1998.274.6.G1031.
The labile iron pool (LIP) represents the nonferritin-bound, redox-active iron that has been implicated in oxidative stress and cell injury. Here we examined whether alterations in LIP can be detected in cultured murine hepatocytes and whether increases in LIP are related to the oxidative damage inflicted by the redox cycling drug nitrofurantoin (NFT). Early changes in LIP were monitored with the metal-sensitive fluorescent probe calcein (CA), the fluorescence of which is quenched on binding to iron. Short-term exposure (<1 h) to NFT reduced the CA fluorescence signal by 30%, indicating that the amount of LIP-associated iron had increased. Prolonged exposure (2 h) to NFT caused oxidative cell injury. The addition of the cell-permeable ferrous iron chelator 2,2'-bipyridyl not only prevented the quenching of CA fluorescence but also partially protected from NFT toxicity. It is concluded that reductive stress-induced increase in LIP is an essential event that precedes oxidative cell damage in intact hepatocytes.
不稳定铁池（LIP）代表未与铁蛋白结合的、具有氧化还原活性的铁，它与氧化应激和细胞损伤有关。在此，我们研究了在培养的小鼠肝细胞中是否能检测到LIP的变化，以及LIP的增加是否与氧化还原循环药物呋喃妥因（NFT）造成的氧化损伤有关。使用金属敏感荧光探针钙黄绿素（CA）监测LIP的早期变化，其荧光在与铁结合时会淬灭。短期暴露（<1小时）于NFT可使CA荧光信号降低30%，表明与LIP相关的铁量增加。长时间暴露（2小时）于NFT会导致细胞氧化损伤。添加细胞可渗透的亚铁螯合剂2,2'-联吡啶不仅能防止CA荧光淬灭，还能部分保护细胞免受NFT毒性影响。结论是，还原应激诱导的LIP增加是完整肝细胞氧化损伤之前的一个关键事件。
