Assessment of Simultaneous Injection of Neural Stem Cells and (-)-Deprenyl to Improve Contusive Spinal Cord Injury in Rats

Objective: Assessment of functional recovery of neural stem cells (NSCs) and (-)-deprenyl, in a contusive spinal cord injury model in rats. Materials and Methods: A total of 24 female Sprague Dawley rats were randomly, but equally (n=6), allocated into the following groups: control, sham, NSC graft and NSC graft + (-)-deprenyl. All animals were laminectomized at the T13 level. Contusion was performed according to the weight dropping technique in the control, NSC and NSC graft + (-)-deprenyl groups. Daily injections of 0.1 mg/kg (ip) (-)-deprenyl were administered to the NSC graft + (-)-deprenyl group and an equal amount of saline into the other groups for 14 days. The NSC graft and NSC graft + (-)-deprenyl groups received stereotaxic injections of 100,000 labelled NSCs at day nine after injury. Behavioral Basso, Beattie and Bresnahan (BBB) test was carried out in all groups at day one (after the contusion day) and at the end of each week for eight weeks. In addition, cavity and spared tissue volume at the site of injury and number of motoneurons at frozen sections of spinal cord were obtained and compared by ANOVA. Differentiation of grafted NSCs into astrocytes, oligodendrocytes and neurons were evaluated by immunohistochemistry. Results: Motor ability of the NSC graft + (-)-deprenyl group in comparison with the control and NSCs groups increased significantly at the end of the study. The mean volume of spared spinal cord and mean number of motoneurons significantly increased in the NSCs and NSC graft + (-)-deprenyl groups compared with the control group. Immunohistochemical evaluations revealed that the grafted NSCs were alive at the end of the study and differentiated into astrocyes, oligodendrocytes and neurons in both the NSCs and NSC graft + (-)-deprenyl groups. In addition, in the NSCs graft group, transplanted cells mainly concentrated around the cavity and showed less differentiation, while in the NSCs graft + (-)-deprenyl group transplanted cells were more scattered and differentiated into one of the above mentioned cell lines. Conclusion: The results of the present study indicate that (-)-deprenyl and NSCs, probably via protection of motoneurons, spinal cord tissue and replacement of lost cells, improves motor recovery in a contusive SCI model in rats.