Reactive oxygen metabolite-induced toxicity to cultured bovine endothelial cells: Status of cellular iron in mediating injury
✍ Scribed by Hideyuki Hiraishi; Akira Terano; Mahnaz Razandi; Ali Pedram; Tsuneaki Sugimoto; Takashi Harada; Kevin J. Ivey
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 967 KB
- Volume
- 160
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
We aimed to determine the status of iron in mediating oxidant-induced damage to cultured bovine aortic endothelial cells. Chromium-51-labeled cells were exposed to reaction mixtures of xanthine oxidase/hypoxanthine and glucose oxidasefglucose; these produce superoxide and hydrogen peroxide, or hydrogen peroxide, respectively. Xanthine oxidase caused a dose dependent increase of 51Cr release. Damage was prevented by allopurinol, oxypurinol, and extracellular catalase, but not by superoxide disrnutase. Prevention of xanthine oxidase-induced damage by catalase was blocked by an inhibitor of catalase, aminotriazole. Glucose oxidase also caused a dose-dependent increase of "Ci release. Glucose oxidase-induced injury, which was catalase-inhibitable, was not prevented by extracellular superoxide dismutase. Both addition of and pretreatment with deferoxamine (a chelator of Fe3+) prevented glucose oxidase-induced injury. The presence of phenanthroline (a chelator of divalent Fe2+) prevented glucose oxidase-induced "Cr release, whereas pretreatment with the agent did not. Apotransferrin (a membrane impermeable iron binding protein) faiied to influence damage. Neither deferoxamine nor phenanthroline influenced cellular antioxidant defenses, or inhibited lysis by non-oxidant toxic agents. Treatment with allopurinol and oxypurinol, which inhibited cellular xanthine oxidase, failed to prevent glucose oxidase injury. We conclude that (1) among the oxygen species extracellularly generated by xanthine oxidase/hypoxanthine, hydrogen peroxide induces damage via a reaction on cellular iron; (2) deferoxamine and phenanthroline protect cells by chelating Fe3+ and Fe2+, respectively; and (3) reduction of cellular stored iron (Fe3+) to Fe*+ may be a prerequisite for mediation of oxidantinduced injury, but this occurs independently of extracellular superoxide or cellular xanthine oxidase-derived superoxide.