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Author(s): Chang, Huiyi H; Yeh, Jih-Chao; Mao, Jackie; Ginsberg, David A; Ghoniem, Gamal; Rodriguez, Larissa V | Abstract: AimInterstitial cystitis/painful bladder syndrome/(IC/PBS) results in recurring pain in the bladder and surrounding pelvic region caused by abnormal excitability of micturition reflexes. Spinal cord stimulation (SCS) is currently clinically used for the attenuation of neuropathic and visceral pain. The present study examined whether SCS at upper lumbar segments modulates detrusor overactivity and visceral hyperalgesia associated with cystitis in a rat model of cyclophosphamide (CYP)-induced cystitis.MethodsCystitis was induced by intraperitoneal injection of CYP (200 mg/kg) in six adult female Sprague Dawley rats 48 h prior to urodynamic recordings. Another six rats served as-controls with saline injection. Cystometry and the external urethral sphincter (EUS) electromyography during bladder infusion were evaluated under urethane anesthesia. The visceromotor reflexes (VMR) obtained from the external abdominal oblique muscle were quantified during bladder infusion and isotonic bladder distension (IBD), respectively. After baseline recordings were taken, SCS was applied on the dorsal surface of L3 for 25 min. Urodynamic recordings and VMR during bladder infusion and IBD were repeated 2 h after SCS.ResultsCYP resulted in detrusor overactivity, stronger EUS tonic contractions, and increased VMR. SCS significantly reduced non-voiding contractions, prolonged EUS relaxation, and delayed VMR appearance during bladder infusion as well as significantly decreased VMR during IBD in cystitis rats.ConclusionSCS improved bladder function and EUS relaxation during bladder infusion and significantly attenuated visceral nociceptive-related VMR during IBD in cystitis rats. SCS may have therapeutic potential for patients with hyperalgesia and IC/PBS.

OBJECTIVE: The underlying mechanism of interstitial cystitis/bladder pain syndrome (IC/BPS) is not well understood and evaluation of current therapeutic interventions have not identified any generally effective treatments. Physical activity has shown beneficial effects on individuals suffering from chronic pain. Anxiety-prone rats exposed to water avoidance stress (WAS) develop urinary frequency and lower bladder sensory thresholds with high face and construct validity for the study of IC/BPS. The aim of this study was to evaluate the role of chronic voluntary exercise on urinary frequency, voiding function, and hyperalgesia in animals exposed to WAS. MATERIALS AND METHODS: Twenty-six female Wistar-Kyoto rats were exposed to WAS and thereafter randomized to either voluntary exercise for 3 weeks or sedentary groups. Voiding parameters were assessed at baseline, post-WAS, and weekly for 3 weeks. Prior to euthanasia, the animals underwent cystometrogram (CMG), external urinary sphincter electromyography (EUS EMG), and assessment of visceromotor response (VMR) to isotonic bladder distension (IBD). RESULTS: WAS exposure resulted in adverse changes in voiding parameters. Compared to sedentary animals, animals in the voluntary exercise group had improved voiding parameters during metabolic cage and CMG testing, as well as improved bladder sensory thresholds as determined by VMR during IBD. CONCLUSION: Voluntary exercise in an animal model of chronic stress leads to improvement in voiding function and visceral bladder hyperalgesia.