Research Of Cross-sectioned Spinal Cord Repaired By Acellular Neural Scaffolds Seeded With PMSCs

Spinal cord injury(SCl) is a common disease in clinical,which leads to severe functional disability.Spontaneous regeneration remains a challenging issue due to poor regeneration capacity of neurons and inhibitory microenvironment.Tissue engineering approaches might be a promising approach with the purpose of reconstruction of inherent structure and environment.In this study,we built graft-PMSCs construct to bridge a 2mm injury gap after severe SCI,providing theoretical foundation for the clinical application of tissue engineering to treat spinal cord injury.Firstly, modified acellular grafts were manufactured and observe the cell nerve scaffold tissue morphological characteristics by HE staining and toluidine blue staining,Laminin immunofluorescence,observe the ultrastructure of acellular scaffolds by scanning electron microscopy (SEM) and transmission electron microscope(TEM),measure DNA content by DNA quantitative detection,evaluate cell toxicity and biological compatibility of acellular scaffolds by cell proliferation and muscle embedment inflammation reaction,construct scaffolds complex by scatter injection of placenta mesenchymal stem cells into acellular scaffolds,observe cell adhesion and growth by frozen section and scanning electron microscope.Then,build cell-scaffold constructs seeded with human placenta mesenchymal stem cells (PMSCs).Afterwards, made rat spinal cord injury animal model and implant the nerve construct.BBB score and foot analysis were performed to test behavior.Immunofluorescence was done to observe growth,migration,and differentiation of the transplanted cells:electrophysiological evoked potential test the formation of the neural circuits;transmission electron microscope to observe the myelin formation.HE staining,boluidine blue staining and TEM results show that the modified acellular scaffold,cells were removed thoroughly,SEMshows that space structure of the scaffolds was intact,the pipe is smooth,the scaffolds were nontoxic and had good biocompatibility.8w after transplantation,fluorescence microscope observation demonstrated numerous PMSCs survived well and differentiated to neurons largely.PMSCs-grafted animals demonstrated significant function improvement tested by BBB scores and foot analysis. Neural pathway was reconnected with enhanced remyelination,confirmed by MEP and TEM respectively.Our data suggests that the modified acellular nerve scaffold was suitable for cell adhesion and growth,provides an ideal scaffold for the construction of tissue-engineered neural complex.PMSCs-derived neurons embedded in acellular graftscould penetrate into host spinal cord and act as neuron-relay for neural circuit reformation,providing theory support for therapy of spinal cord injury clinically.