Local versus distal transplantation of human neural stem cells following chronic spinal cord injury

Background Context Previous studies have demonstrated functional recovery of rats with spinal cord contusions after transplantation of neural stem cells adjacent to the site of acute injury. Purpose The purpose of the study was to determine if the local or distal injection of neural stem cells can cause functional difference in recovery after chronic spinal cord injury. Study Design/Setting Twenty-four adult female Long-Evans hooded rats were randomized into four groups, with six animals in each group: two experimental and two control groups. Functional assessment was measured after injury and then weekly for 6 weeks using the Basso, Beattie, and Bresnahan locomotor rating score. Data were analyzed using two-sample t test and linear mixed-effects model analysis. Methods Posterior exposure and laminectomy at the T10 level was used. Moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor with 10-g weight dropped from a height of 25 mm. Experimental subjects received either a subdural injection of human neural stem cells (hNSCs) locally at the injury site or intrathecal injection of hNSCs through a separate distal laminotomy 4 weeks after injury. Controls received control media injection either locally or distally. Results A statistically significant functional improvement in subjects that received hNSCs injected distally to the site of injury was observed when compared with the control (p=.042). The difference between subjects that received hNSCs locally and the control did not reach statistical significance (p=.085). Conclusions The transplantation of hNSCs into the contused spinal cord of a rat led to significant functional recovery of the spinal cord when injected distally but not locally to the site of chronic spinal cord injury.