Stereotaxic Transplantation Of Bone Mesenchymal Stem Cells For Treating Spinal Cord Injury In Rats

OBJECTIVE:To explore the effects and mechanisms of bone marrow mesenchymal stem cells (BMSCs) locally transplanted into rats with spinal cord injury on neurological recovery.METHODS:BMSCs were separated with density gradient centrifugation and cell attachment.10mg/L BrdU was used for labeling before cell transplantation. Adult female Wistar rats were used to establish spinal cord injury models using an aneurysm clip, and they were then randomly divided into control group, saline group and transplantation group. In the transplantation group, BMSCs were transplanted into the damaged spinal cord by stereotaxis at day7following damage. In the saline group, an equal volume of saline was utilized. In the control group, the rats were left intact. Basso, Beattie and Bresnahan (BBB) locomotor rating scale was used before and at7,14.30,60and90days following damage. Somatosensory evoked potential(SEP) and moter evoked potential(MEP) tests were performed before injury,and7、14、30、60、90days after the SCI surgery. Rats were sacrificed at day90. BrdU-positive cells, Brdu+neuron specific enolase, Brdu+glial fibrillary acidic protein (GFAP), Brdu+basic fibroblast growth factor (bFGF), and Brdu+brain-derived nerve growth factor (BDNF) immunohistochemistry double-staining cells and simple staining positive cells were observed.RESULTS:The BMSCs transplantation group showed higher BBB scores than the control group (P<0.05). The recovery speed of BBB function score was slower in the saline group than in the control group at30days following damage (P<0.05), b ut no significant difference was determined at day90between the control group and the saline group (P>0.05). Since the30th day after injury, the motor evoked potential latency and somatosensory evoked potential PI wave latency of the BMSCs transplantation group were shorter than those of the control group (P<0.05), and these phenomena continued until the end of experiment. BrdU-positive cells and double-staining cells of immunohistochemistry could be found at the center of damage site and1cm from caudal end to damaged site in rats of the transplantation group.CONCLUSION:Results indicated that BMSC transplantation can improve the recovery of nervous function of rats with spinal cord injury. Its mechanism may be correlated with the differentiation of transplanted cells into neuron-like and glial cell-like cells, secretion or promoting secretion of neurotrophic factors in host.