• Shogo Shimizu, Motoaki Saito, Yukako Kinoshita, Emi Kazuyama, Mayuko Tamamura, Itaru Satoh, and Keisuke Satoh.
• Division of Molecular Pharmacology, Department of Pathophysiological and Therapeutic Science, Tottori University Faculty of Medicine, Yonago City, Tottori, Japan.
• BJU Int. 2009 Sep 1;104(5):713-7.

ObjectiveTo investigate the effect of a free-radical scavenger, edaravone, on the changes occurring with acute urinary retention (AUR) and subsequent catheterization in the rat bladder.Materials And MethodsEight-week-old male Sprague Dawley rats were allocated to one of four groups; an AUR group that had urinary retention induced, with subsequent catheterization; two edaravone groups, given edaravone at 1 or 10 mg/kg body weight for 60 min and then the same urinary retention and subsequent catheterization; and a sham-operated control group given edaravone 10 mg/kg. Urinary retention was induced by the clamping the rat penile urethra with a small clip, making a cystostomy, and then infusing 3 mL (0.6 mL/min) of saline with an infusion pump. The obstruction was sustained for 30 min and then the bladder was allowed to drain with a catheter in place for 60 min as the studies continued. After killing the rats the function of the bladder was assessed, with carbachol and 100 mM KCl, and the levels of malondialdehyde (MDA, a marker of lipid peroxidation), 8-hydroxydeoxyguanosine (8-OHdG; a marker of oxidative DNA damage), heat-shock protein 70 (HSP 70) and its mRNA were measured.ResultsAUR increased the intravesical pressure and decreased blood flow, and subsequent catheterization decreased the intravesical pressure and increased blood flow. Edaravone induced a decrease in blood flow in the bladder during the urinary retention and subsequent catheterization compared to the blood flow in the AUR group. Edaravone resulted in protection of the contractile responses to both carbachol and KCl in a dose-dependent manner. The MDA concentration, 8-OHdG content and expressions of HSP-70 and its mRNA in the AUR group were significantly larger than those of the control group. Edaravone markedly suppressed the accumulations of MDA and 8-OHdG in the bladder, and reduced the expressions of HSP 70 and its mRNA.ConclusionThese results indicate that edaravone reduces the oxidative stress and prevents the bladder dysfunction caused by AUR and subsequent catheterization.

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