Transurethral versus suprapubic catheterization to test urethral function in rats

Transurethral and suprapubic catheterization have both been used to test urethral function in rats; however, it is unknown whether these methods affect urethral function or if the order of catheterization affects the results. The aim of this cross-over designed experiment was to compare the effects of catheterization methods and order on leak point pressure (LPP) testing. LPP and simultaneous external urethral sphincter electromyography (EUS EMG) were recorded in anesthetized female virgin Sprague-Dawley rats in a cross-over design to test the effects of transurethral and suprapubic catheterization. There was no significant difference in peak bladder pressure during LPP testing whether measured with a transurethral or suprapubic catheter. There was no significant difference in peak bladder pressure between the first and second catheter insertions. However, peak EMG firing rate, as well as peak EMG amplitude and EMG amplitude difference between peak and baseline were significantly higher after the first catheter insertion compared to the second insertion, regardless of the catheter method. Our results suggest that route of catheterization does not alter urethral function, e.g. create a functional partial outlet obstruction. Either catheterization method could be used for LPP and/or EUS EMG testing in rats

Multiple doses of stem cells maintain urethral function in a model of neuromuscular injury resulting in stress urinary incontinence

Stress urinary incontinence (SUI) is more prevalent among women who deliver vaginally than women who have had a cesarean section, suggesting that tissue repair after vaginal delivery is insufficient. A single dose of mesenchymal stem cells (MSCs) has been shown to partially restore urethral function in a model of SUI. The aim of the present study was to determine if increasing the number of doses of MSCs improves urethral and pudendal nerve function and anatomy. We hypothesized that increasing the number of MSC doses would accelerate recovery from SUI compared with vehicle treatment. Rats underwent pudendal nerve crush and vaginal distension or a sham injury and were treated intravenously with vehicle or one, two, or three doses of 2 × 10 6 MSCs at 1 h, 7 days, and 14 days after injury. Urethral leak point pressure testing with simultaneous external urethral sphincter electromyography and pudendal nerve electroneurography were performed 21 days after injury, and the urethrovaginal complex and pudendal nerve were harvested for semiquantitative morphometry of the external urethral sphincter, urethral elastin, and pudendal nerve. Two and three doses of MSCs significantly improved peak pressure; however, a single dose of MSCs did not. Single, as well as repeated, MSC doses improved urethral integrity by restoring urethral connective tissue composition and neuromuscular structures. MSC treatment improved elastogenesis, prevented disruption of the external urethral sphincter, and enhanced pudendal nerve morphology. These results suggest that MSC therapy for postpartum incontinence and SUI can be enhanced with multiple doses