title: Iron supplementation generates hydroxyl radical in vivo. An ESR spin-trapping investigation.
abstract: Electron spin resonance (ESR) spectroscopy has been used to investigate hydroxyl radical generation in rats with chronic dietary iron loading. A secondary radical spin-trapping technique was used where hydroxyl radical forms methyl radical upon reaction with DMSO. The methyl radical was then detected by ESR spectroscopy as its adduct with the spin trap alpha-phenyl-N-t-butylnitrone (PBN). This adduct was detected in the bile of rats 10 wk after being fed an iron-loading diet and 40 min after the i.p. injection of the spin trap PBN dissolved in DMSO. Bile samples were collected into a solution of the ferrous stabilizing chelator 2,2'-dipyridyl in order to prevent the generation of radical adducts ex vivo during bile collection. Identification of the ESR spectrum of the major radical adduct as that of PBN/.CH3 provides evidence for the generation of the hydroxyl radical during iron supplementation. Desferal completely inhibited in vivo hydroxyl radical generation stimulated by high dietary iron intake. No radical adducts were detected in rats which were fed the control diet for the same period of time. This is the first evidence of hydroxyl radical generation in chronic iron-loaded rats.
authors.affiliation: National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Kadiiska
authors.forename: M J
authors.initials: MJ
authors.lastname: Burkitt
authors.forename: Q H
authors.initials: QH
authors.lastname: Xiang
authors.forename: R P
authors.initials: RP
authors.lastname: Mason
mesh_terms: D015082:2,2'-Dipyridyl; D015720:5'-Nucleotidase / Q000097:blood; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000821:Animal Feed; D000818:Animals; D001647:Bile Acids and Salts / Q000097:blood; D003497:Cyclic N-Oxides; D003676:Deferoxamine / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide; D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D005527:Food, Fortified; D017665:Hydroxyl Radical / Q000378:metabolism*; D007501:Iron / Q000097:blood; D007064:L-Iditol 2-Dehydrogenase / Q000097:blood; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009589:Nitrogen Oxides; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D013113:Spin Labels
chemical_list: D001647:Bile Acids and Salts; D003497:Cyclic N-Oxides; D005290:Ferric Compounds; D009589:Nitrogen Oxides; D013113:Spin Labels; D017665:Hydroxyl Radical; C029217:phenyl-N-tert-butylnitrone; D015082:2,2'-Dipyridyl; C025314:ferric citrate; D007501:Iron; D007064:L-Iditol 2-Dehydrogenase; D007770:L-Lactate Dehydrogenase; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D015720:5'-Nucleotidase; D003676:Deferoxamine; D004121:Dimethyl Sulfoxide