Bone Marrow Mesenchymal Stem Cells Promote Functional Recovery after Spinal Cord Injury in Rats

Objective:To explore the mechanism of functional recovery after spinal cord injury (SCI) in rats with bone marrow mesenchymal stem cells (BMSCs) and the therapeutic effect. Methods:The rat’s SCI model was made by NYU Impactor-II at T10. After cell permanent planting was confirmed by preliminary experiment of cell transplantation, the BMSCs which passed 10 stable passages in vitro were grafted into the injured epicenter of spinal cord on 3rd d (group Ⅱ) and 1st w (groupⅢ) respectively after injury. DMEM was set as control (groupⅠ). The basso beattie bresnahan(BBB)score and footprint analysis were carried out to evaluate functional recovery of rat’s hind limbs after injury. Three months later, all rats were sacrificed. The injured spinal cord was taken out to make a 10 μm fast frozen section, which was followed by HE, NF and ED1 immunohistochemistry staining. The percentage of positive response area was assayed to compare between groups. Results: The doubling cycle of BMSCs was around 2~3 days. On the 4th w after injury, statistical difference of BBB score happened among three groups (P 0.05 or P 0.01), while on the 6th w after injury, statistical difference of footprint analysis appeared between group Ⅱ and group Ⅲ (P 0.05 or P 0.01). The statistical differences also existed between the three groups after comparing the percentage of positive response area of NF and ED1 immunohistochemistry staining (P 0.05 or P 0.01). Conclusion: The graft of BMSCs improves microenvironment of injured spinal cord and promotes axonal regeneration as well as functional recovery after SCI in rats.