title: Indoxyl sulfate reduces superoxide scavenging activity in the kidneys of normal and uremic rats.
abstract: OBJECTIVE
  Indoxyl sulfate (IS) is a uremic toxin that accelerates the progression of chronic renal failure (CRF). This study aimed at determining whether IS impairs antioxidative systems (redox status) in the kidney.
  
  
  METHODS
  IS was orally administered to normal and subtotally nephrectomized (three fourths and five sixths) rats (CRF rats) for 2 weeks. By use of in vivo and ex vivo electron spin resonance spectroscopy, the kidney redox status was evaluated using carbamoyl-PROXYL as a radical spin probe in living rats, and the kidney superoxide scavenging activity was measured. Immunohistochemistry of superoxide dismutase (SOD) in the kidney was performed.
  
  
  RESULTS
  Administration of IS increased serum and kidney levels of IS and serum creatinine and decreased creatinine clearance. CRF rats showed reduced spin reduction rate, prolonged half-life of the spin probe, and reduced superoxide scavenging activity and SOD-positive areas in the kidney as compared with normal rats. Administration of IS further reduced radical spin reduction rate, prolonged half-life of the spin probe, and reduced superoxide scavenging activity and SOD-positive areas in the kidneys.
  
  
  CONCLUSIONS
  Administration of IS reduced superoxide scavenging activity in the kidneys of normal and CRF rats. Thus, the nephrotoxicity of IS may be induced by impairing the antioxidative systems in the kidney.
authors.affiliation: Dialysis Unit, Asao Clinic, Kawasaki, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Owada
authors.forename: Sumie
authors.initials: S
authors.lastname: Goto
authors.forename: Kenji
authors.initials: K
authors.lastname: Bannai
authors.forename: Hideo
authors.initials: H
authors.lastname: Hayashi
authors.forename: Fuyuhiko
authors.initials: F
authors.lastname: Nishijima
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Niwa
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000378:metabolism*; D006207:Half-Life; D007150:Immunohistochemistry; D007200:Indican / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D007676:Kidney Failure, Chronic / Q000378:metabolism*; D011759:Pyrrolidines; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D014511:Uremia / Q000378:metabolism
chemical_list: C499782:3-carboxy-2,2,5,5-tetramethylpyrrolidin-1-yloxyl; D003497:Cyclic N-Oxides; D016166:Free Radical Scavengers; D011759:Pyrrolidines; D013481:Superoxides; D013482:Superoxide Dismutase; D007200:Indican