Immortalized neural stem cells transplanted into the injured spinal cord promote recovery of voiding function in the rat

Purpose: Bladder dysfunction is a serious consequence of spinal cord injury. Cellular transplantation into the injured spinal cord can promote axonal growth and functional recovery. We investigated whether EG6 immortalized neural stem cells transplanted into the injured spinal cord of the rat contribute to a recovery of lower urinary tract function. Materials and Methods: The spinal cord of 14 female Wistar rats was injured by compression. In 7 rats 9 days after spinal cord injury BrdU (5-bromo-2'-deoxyuridine) labeled EG6 cells were transplanted into the injured spinal cord. Seven operated (OP) control rats received intraspinal injections of culture medium alone. Voided volume per micturition was assessed in a metabolic cage for 24 hours on days 14 and 28 after transplantation. On day 28 saline was infused via a catheter inserted into the bladder and intravesical pressure was measured in OP control and EG6 transplant rats. Results: EG6 cells identified by BrdU immunocytochemistry survived in the injured spinal cord. Voided volume per micturition significantly increased in EG6 transplant rats by day 28 after transplantation. Micturition pressure significantly decreased in EG6 transplant rats compared with OP controls. Although voided volume did not differ, post-void residual urine was significantly less in EG6 transplant than in OP control rats. Thus, voiding efficiency was significantly greater in EG6 transplant rats compared with OP controls. There was no difference in the incidence of detrusor hyperreflexia. Conclusions: Transplanted EG6 cells survived in the injured spinal cord and had beneficial effects on the recovery of voiding function after spinal cord injury in the rat.