Therapeutic effect of bone marrow mesenchymal stem cell transplantation for spinal cord injury / 中国组织工程研究

ABSTRACT

BACKGROUND: At present, treatments for spinal cord injury are limited, with poor outcomes. Therefore, it is of great importance to explore new treatment methods. OBJECTIVE:To observe the therapeutic effect of bone marrow mesenchymal stem cells(BMSCs)injection via the caudal vein on spinal cord injury in rats. METHODS:BMSCs were isolated and cultured in vitro by whole bone marrow adherence method.The surface markers were identified by flow cytometry. Thirty Sprague-Dawley rats were randomly divided into control group, spinal cord injury group and BMSCs transplantation group, 10 rats in each group. A rat spinal cord injury model was established by occlusion of the 10ththoracic vertebra using an aneurysm clamp, and 2×106BMSCs were injected through the caudal vein at 10 minutes after modeling. Basso-Bettle-Bresnahan (BBB) score for motor function recovery was assessed at 0, 10, 20, 30 days after transplantation. The therapeutic effect was evaluated by hematoxylin-eosin staining and electron transmission microscopy at 30 days after implantation. RESULTS AND CONCLUSION: Under the microscope, fusiformis-shaped or fibroblast-like cells were observed. The expression rate of CD44 and CD90 was more than 90% and the expression of CD45 was less than 2%, by which, the BMSCs were identified. The BBB scores were significantly higher in the BMSCs transplantation group than the spinal cord injury group at 20 and 30 days after transplantation (P < 0.05). Hematoxylin-eosin staining showed that there was spinal cord tissue damage, vascular rupture injury, neuronal cell degeneration and inflammatory cell infiltration in the spinal cord injury group. After BMSCs transplantation, the number of spinal cord neurons was markedly increased with intact cytomembrane and clear nucleolus. Electron microscopic results showed that spinal cord axon swelling, demyelination, nerve axon deformation and necrosis were observed in the spinal cord injury group, while after BMSCs transplantation, the rat spinal cord axon structure was repaired,and partially lost myelin was recovered with uniform thickness.To conclude,BMSCs transplantation via the caudal vein has a significant therapeutic effect on spinal cord injury in rats by repairing the spinal cord structure and protecting the integrity of axon and myelin structures.