Portal de Periódicos da CAPES

The labile iron pool in hepatocytes: prooxidant-induced increase in free iron precedes oxidative cell injury

1998; American Physiological Society; Volume: 274; Issue: 6 Linguagem: Inglês

10.1152/ajpgi.1998.274.6.g1031

1522-1547

Anna Stäubli, Urs A. Boelsterli,

Drug Transport and Resistance Mechanisms

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.