Functional Recovery after the Transplantation of Neurally Differentiated Mesenchymal Stem Cells Derived from Bone Marrow in a Rat Model of Spinal Cord Injury

This study was designed to investigate functional recovery after the transplantation of mesenchymal stem cells (MSCs) or neurally differentiated MSCs (NMSCs) derived from bone marrow in a rat model of spinal cord injury (SCI). Sprague-Dawley rats were subjected to incomplete SCI using an NYU impactor to create a free drop contusion at the T9 level. The SCI rats were then classified into three groups; MSCs, NMSCs, and phosphate-buffered saline (PBS)-treated groups. The cells or PBS were administrated 1 week after SCI. Basso-Beattie-Bresnahan (BBB) locomotor rating scores were measured at 1-week intervals for 9 weeks. Somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) were also recorded 8 weeks after transplantation. While transplantation of MSCs led to a clear tendency of motor recovery, NMSC-treated rats had significantly improved BBB scores and showed significantly shortened initial latency, N1 latency, and P1 latency of the SSEPs compared to PBS controls. In addition, 5-bromo-2-deoxyuridine (BrdU)-prelabeled MSCs costained for BrdU and glial fibrillary acidic protein (GFAP) or myelin basic protein (MBP) were found rostrally and caudally 5 mm each from the epicenter of the necrotic cavity 4 weeks after transplantation. These results suggest that neurally differentiated cells might be an effective therapeutic source for functional recovery after SCI.