Contribution of pudendal nerve injury to stress urinary incontinence in a male rat model

TL;DR

This study shows that injury to the pudendal nerve in male rats leads to urinary incontinence, offering a model for testing treatments.

Contribution

The study introduces a male rat model to investigate pudendal nerve injury's role in post-prostatectomy incontinence.

Findings

Acute pudendal nerve transection significantly reduced leak point pressure and EMG activity in male rats.

Pudendal nerve crush caused long-term reductions in leak point pressure and EMG firing rate.

Neuromuscular junctions were less organized after pudendal nerve injury, with increased collagen infiltration.

Abstract

Urinary incontinence is a common complication following radical prostatectomy, as the surgery disturbs critical anatomical structures. This study explored how pudendal nerve (PN) injury affects urinary continence in male rats. In an acute study, leak point pressure (LPP) and external urethral sphincter electromyography (EMG) were performed on six male rats with an intact urethra, the urethra exposed (UE), the PN exposed (NE), and after PN transection (PNT). In a chronic study, LPP and EMG were tested in 67 rats 4 days, 3 weeks, or 6 weeks after sham PN injury, PN crush (PNC), or PNT. Urethras were assessed histologically. Acute PNT caused a significant decrease in LPP and EMG amplitude and firing rate compared to other groups. PNC resulted in a significant reduction in LPP and EMG firing rate 4 days, 3 weeks, and 6 weeks later. EMG amplitude was also significantly reduced 4 days and 6 weeks after PNC. Neuromuscular junctions were less organized and less innervated after PNC or PNT at all timepoints compared to sham injured animals. Collagen infiltration was significantly increased after PNC and PNT compared to sham at all timepoints. This rat model could facilitate preclinical testing of neuroregenerative therapies for post-prostatectomy incontinence.

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