Stress urinary incontinence (SUI) in women is strongly associated with childbirth which injures the pudendal nerve (PN) and the external urethral sphincter (EUS) during delivery. Electrical stimulation (ES) can increase brain-derived neurotrophic factor (BDNF) expression in injured neurons, activate Schwann cells and promote neuroregeneration after nerve injury. The aim of this study was to determine if more frequent ES would increase recovery from SUI in a rat model. Forty female Sprague-Dawley rats underwent either sham injury or pudendal nerve crush (PNC) and vaginal distention (VD) to establish SUI. Immediately after injury, electrodes were implanted at the pudendal nerve bilaterally. Each injured animal underwent sham ES, twice per week ES (2/week), or daily ES of 1 h duration for two weeks. Urethral and nerve function were assessed with leak point pressure (LPP), EUS electromyography and pudendal nerve sensory branch potential (PNSBP) recordings two weeks after injury. LPP was significantly increased after daily ES compared to 2/week ES. EUS neuromuscular junction innervation was decreased after injury with sham ES, but improved after 2/week or daily ES. This study demonstrates that daily bilateral ES to the pudendal nerve can accelerate recovery from SUI. Daily ES improved urethral function more than 2/week ES.
Keywords: external urethral sphincter; leak point pressure; nerve regeneration; neurourology; urodynamics.