Management of urinary and bowel dysfunction in rabbit model of spinal cord injury using Schwann cells and muscle progenitors: functional study and evidence for novel mechanism of action.

Purpose: We tried to investigate the role of Schwann and satellite cells in the treatment of neurogenic bladder and bowel dysfunction; following spinal cord injury in the rabbit model.

Methods: Twelve male New Zealand rabbits underwent induction of neurogenic bladder by spinal cord injury. Rabbits underwent the fiber tractography analysis to confirm the induction of spinal cord injury. Then, animals were randomly divided into two groups. In group I (n = 4), Schwann cells were obtained from autologous peroneal nerve. In group II (n = 4), the co-culture of nerve-muscle cells was obtained from autologous peroneal nerve and quadriceps muscle. Animals in the control group (n = 4) did not undergo any rehabilitation therapy. One and 4 months after injection of cells into the external anal sphincter, electromyography, urethral pressure profiles, urodynamic studies, voiding cystourethrogram, and manometry was performed to confirm the efficacy of treatment in short- (1 month) and long-term (4 months) follow-ups.

Results: The investigations validated that no statistically significant difference was detected between the two experimental groups in a short-term follow-up (p-value > 0.05). However, the functional features were improved in group II in long-term follow-up. In both groups, the external anal sphincter contracted in response to electrical signals delivered to the muscle. However, more signals were detected in group II in electromyography evaluation. The immunohistochemical staining demonstrated that the histological features of the bladder and spinal cord were more satisfactory in group II in all follow-ups compared to group I, in terms of less edema, inflammation, presence of progenitor cells, and expression of muscle and nerve markes.

Conclusion: Our results suggested that the injection of nerve-muscle co-culture cells into the external anal sphincter may be a helpful tactic for ameliorating the urological complications; following spinal cord injury induction in the rabbit model.