Reduction of oxidative stress in cultured renal tubular cells and preventive effects on renal stone formation by the bioflavonoid quercetin.
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.
Park
Hyoung Keun
HK
Department of Urology, Seoul National University College of Medicine and Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. hhkim@snu.ac.kr [corrected]
Jeong
Byong Chang
BC
Sung
Mi-Kyung
MK
Park
Mi-Young
MY
Choi
Eun Young
EY
Kim
Bong Sub
BS
Kim
Hyeon H
HH
Kim
Jeong In
JI
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
D000975:Antioxidants; D011794:Quercetin