255 DRAMATIC REDUCTION IN URETHRAL SPHINCTER ACTIVITY FOLLOWING PELVIC NERVE CRUSH IN THE RAT

Abstract

You have accessJournal of UrologyBladder and Urethra: Anatomy, Physiology and Pharmacology I1 Apr 2012255 DRAMATIC REDUCTION IN URETHRAL SPHINCTER ACTIVITY FOLLOWING PELVIC NERVE CRUSH IN THE RAT Christopher Chermansky, Qiang Wu, J. Christian Winters, and Matthew Fraser Christopher ChermanskyChristopher Chermansky New Orleans, LA More articles by this author , Qiang WuQiang Wu New Orleans, LA More articles by this author , J. Christian WintersJ. Christian Winters New Orleans, LA More articles by this author , and Matthew FraserMatthew Fraser Durham, NC More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.312AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES There is no established rat model for euglycemic non-obstructive underactive bladder (UAB). We present such a model for the purpose of testing therapies aimed at improving bladder emptying in patients with this condition. METHODS 44 female SD rats were divided into two experimental groups: bilateral pelvic nerve crush (PNC) and control. PNC was performed in 23 rats under isoflurane anesthesia. A straight Jacobson micro mosquito clamp was used to crush each pelvic nerve for 30 seconds. The crush was performed proximal to each pelvic nerve's entry into the major pelvic ganglion. Prior to crushing, the identity of the pelvic nerve was verified by electrical stimulation with a bipolar electrode to confirm visual bladder contraction. 21 control rats underwent a sham operation where pelvic nerves were exposed but not crushed. At 1, 2, and 4 weeks following PNC or sham surgery, the rats underwent continuous cystometry and external urethral sphincter (EUS) EMG testing under urethane anesthesia (1.2g/kg) using a PE90 transvesical catheter and a saline infusion rate of 0.04 ml/min. Periurethral EUS EMG fine wire electrodes were inserted percutaneously. Finally, isovolumetric cystometry was performed to measure bladder contractile strength by tying off the urethra. Data were collected using PowerLab from AD Instruments. Statistical comparisons between groups were performed using two-way ANOVA with GraphPad from Prism. RESULTS Following PNC, intercontraction interval (ICI) increased at 1 week and remained doubled at 4 weeks during continuous CMG. This was paralleled by similar increases in bladder compliance. A striking reduction (50%) in EUS EMG activity during filling was also seen with PNC. Isovolumetric CMG in the PNC groups revealed a 40% reduction in peak bladder contraction pressures over baseline and a 30% reduction in isovolumetric bladder contraction areas under the curves. CONCLUSIONS In this preliminary study, we have shown that bilateral pelvic nerve crush in the rat is a promising, long-lasting model of UAB, demonstrating both bladder and outlet dysfunction consistent with pelvic nerve denervation. Increased ICI, bladder compliance, and decreased EUS activity are consistent with decreased afferent sensitivity with PNC. Decreased bladder contraction strength is consistent with compromised efferent function. By establishing a chronic rat model for UAB in otherwise normal animals, we can test potential therapies for treating UAB and voiding dysfunction, thereby addressing both afferent and efferent dysfunction. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e103-e104 Peer Review Report Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Christopher Chermansky New Orleans, LA More articles by this author Qiang Wu New Orleans, LA More articles by this author J. Christian Winters New Orleans, LA More articles by this author Matthew Fraser Durham, NC More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...