Driving Micturition with Task-specific Reflex Bladder Training (rBT) Improves Bladder Storage and Voiding Behaviors in Anesthetized Female Rats with Contusion SCI

Spinal cord injury (SCI) exerts a profound negative impact on lower urinary tract (LUT) function, resulting in problems with both urine storage and emptying of the bladder. The functional consequences include neurogenic detrusor over-activity (NDO), high bladder pressures (BP), inefficient voiding, and urine retention that are associated with a high degree of morbidity and a poor quality of life. While bladder management strategies, which often include catheter-based management and/or medications to reduce NDO and BP, minimize some of the negative complications, they do not fix the problems caused by SCI. As such, current approaches to treat bladder dysfunction following SCI are inadequate. In other physiological systems ( e.g., respiratory, somatic motor), strategies for improving functional recovery after SCI often include task-specific training (TST). Whether TST in bladder function could similarly serve as an effective therapeutic strategy for improving recovery of LUT function following SCI remains to be determined. To begin to assess this possibility, we developed and implemented a task-specific ‘fill-void’ bladder infusion strategy to elicit and drive repetitive reflex-mediated functional ‘storage and voiding’ micturition cycles as a novel TST paradigm for reflex bladder training (rBT), and assessed the impact of this approach at 4-weeks after clinically relevant mid-thoracic moderate contusion SCI using acute cystometry and void volume measurements in urethane-anesthetized adult female Sprague-Dawley rats (n=9). Before treatment, saline infusion into the bladder (BL_rate = 0.06 ml/min) elicited non-voiding (NVC) and voiding (VC) bladder contractions (NVC/VC ratio: ≥2) with detrusor-sphincter dyssynergia (DSD) characterized by either absent or weak EUS bursting with incomplete EUS relaxation during voiding. In addition, a fairly large post-void residual volume (PV-RV; 2.413±0.470g) was observed. At ~80-120 min following completion of rBT delivered at 4x BL_rate for 45-min, post-treatment saline infusion into the bladder (BL_rate) included a complete or almost complete elimination of NVCs (NVC/VC ratio: <1), decreases in peak BP (by ~10%, P=0.0066) and min BP (by ~34%, P=0.0514), a reduction in DSD as suggested by the emergence of strong EUS bursting with complete relaxation (which is characteristic in naïve rats), increases in void volume (by ~49%, P=0.0063) and dynamic voiding efficiency (by ~22%, P=0.0889), and a decrease in PV-RV (to 1.809±0.40g; P=0.0324). There was no urine leakage during rBT infusion, and VCs that exhibited reduced peak BP and min BP were the dominant micturition pattern observed. These preliminary findings support the paradigm shifting idea that implementing a task-specific rBT paradigm to elicit and drive repetitive reflex-mediated functional ‘storage and voiding’ micturition cycles can reduce NDO (NVCs), DSD, and urine retention to promote improvements in bladder function following SCI. NYS DOH SCIRB C37711GG This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.