title: Reduction of oxidative stress in cultured renal tubular cells and preventive effects on renal stone formation by the bioflavonoid quercetin.
abstract: OBJECTIVE
  We investigated the effects of quercetin on renal tubular cell injury induced by oxalate and the inhibitory effects of quercetin on urinary crystal deposit formation in an animal model.
  
  
  METHODS
  MDCK cells (American Type Culture Collection, Manassas, Virginia) were incubated with different concentrations of oxalate with and without quercetin. MTT (Sigma) assays for cell viability, malondialdehyde and catalase activity were measured to investigate the antioxidant effect of quercetin. Male Sprague-Dawley rats were divided into 3 groups. Group 1 was fed standard rat chow. Groups 2 and 3 rats were fed standard chow supplemented with 3% sodium oxalate for 4 weeks. For the first 8 days in 4 weeks each rat in groups 2 and 3 also received gentamicin intramuscularly. Additionally, group 3 rats were administered quercetin for 4 weeks. Rats were sacrificed after 4 weeks, after which 24-hour urine collections and kidney removal were performed. In the renal tissue malondialdehyde, superoxide dismutase and catalase activity was measured. Bisected kidneys were examined under microscopy to determine the number of crystals.
  
  
  RESULTS
  The viability of MDCK cells significantly decreased and malondialdehyde production increased in the presence of oxalate. However, co-exposure to quercetin inhibited the decrease in cell viability and inhibited the lipid peroxidation production induced by oxalate. In the animal study malondialdehyde production in group 3 significantly decreased compared to that in group 2. Catalase and superoxide dismutase activity was increased in group 3 compared to that in group 2. The number of crystals in kidneys in group 3 was decreased significantly compared to that in group 2.
  
  
  CONCLUSIONS
  Quercetin has an inhibitory effect on urinary crystal deposit formation.
authors.affiliation: Department of Urology, Seoul National University College of Medicine and Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. hhkim@snu.ac.kr [corrected]
authors.forename: Hyoung Keun
authors.initials: HK
authors.lastname: Park
authors.forename: Byong Chang
authors.initials: BC
authors.lastname: Jeong
authors.forename: Mi-Kyung
authors.initials: MK
authors.lastname: Sung
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Park
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Bong Sub
authors.initials: BS
authors.lastname: Kim
authors.forename: Hyeon H
authors.initials: HH
authors.lastname: Kim
authors.forename: Jeong In
authors.initials: JI
authors.lastname: Kim
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D003460:Crystallization; D007686:Kidney Tubules, Distal / Q000166:cytology / Q000187:drug effects*; D008297:Male; D053040:Nephrolithiasis / Q000517:prevention & control*; D018384:Oxidative Stress / Q000187:drug effects*; D011794:Quercetin / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000975:Antioxidants; D011794:Quercetin