The objective was to design a scaffold that could continuously deliver nerve growth factor (NGF) combined with neurally differentiated bone marrow mesenchymal stem cells (BMSCs) to promote better recovery of spinal cord injury (SCI) in rats. BMSCs were induced to differentiate into neurons for 6 days in vitro, and then seeded on a NGF persistent delivery scaffold, both were transplanted to SCI rats in combination. Relevant extensive tests were conducted 1, 4 and 8 weeks after transplantation. The results showed that the scaffold had a stable ability to continuously release NGF and that the BMSCs on the scaffold could successfully differentiate into nerve cells. The results of Bacco, Beattie and Bresnahan (BBB) scores, inclined plane tests and electrophysiological investigations revealed that the rats in the combined regimen had better locomotor functional recovery. The results of H&E/Nissl staining, Golgi staining and immunofluorescence showed that the rats in the combined regimen retained the most neurons and had the least cavities and more formations of dendritic spines. Similarly, the positive rate was high for MAP2, NeuN and MBP, and low for GFAP. The graft of the NGF persistent delivery scaffold seeded with neurally differentiated BMSCs significantly reduced the formation of cavities and glial scars at the SCI sites and promoted neuronal survival, axonal regeneration and locomotor function recovery. Compared with the single graft of NGF persistent delivery scaffold or the single graft of neurally differentiated BMSCs, this combined scheme had a better effect in promoting the recovery of SCI.
Keywords: Spinal cord injury; bone mesenchymal stem cells; nerve growth factor; neural differentiation; scaffold; transplantation.
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