Effects of Neuromodulation and Temperature on Bladder Function in Rats with Incomplete Spinal Cord Injury

Introduction: Cystometry is an established tool for evaluating bladder function. Bladder function can be used to monitor Spinal Cord Injury (SCI) recovery and assess therapeutics. Previous experiments have examined body temperature effects on cystometric parameters. This study aims to evaluate the effect of electrical stimulation on the temperature related change in cystometric inter-contractile interval (ICI).

Methods: Five female rats were induced with SCI (4 hemi-section 1 complete transection) and implanted with an electrode in the first sacral foramen. The hemi-section animals were equally split into stimulation and non-stimulation groups. The stimulation group received 30 minutes of electrical stimulation daily at 80% motor threshold. After two weeks, cystometry was recorded at 37º C and 32º C in addition to final bladder mass for all animals.

Results: Stimulation group bladder mass was 0.2903 ± 0.0992 grams. Non-stimulation bladder mass was 0.2294 ± 0.0904 grams. The complete SCI rat had a bladder mass of .4509 g. The ICI for the stimulation group increased by 30.9597 ± 13.8609 seconds in the 32º C condition compared to the 37°. Conversely, the sham group had an ICI decrease of 19.7712 ± 0.3554 seconds in the 32º C condition compared to the 37° condition sham. The p-value for these differences in ICI is 0.1225.

Conclusion : Differences in bladder mass may be confounded by duration of bladder recovery. The results have some indication that electrical stimulation may affect bladder function response to temperature. More animal tests are needed as no conclusions can be drawn from such a small sample.