Synapses developing process of fetal spinal cord cells with autologus activated Schwann cells in repairing acute spinal cord injury / 中华骨科杂志

ABSTRACT

ObjectiveTo observe and analyze the synapses developing process of newly generated connections of autologus activated Schwann cells (AASCs) in combination with fetal spinal cord cell suspension(FSCS) in the surrounding area of the spinal cord injury site.MethodsA total of 42 Wistar rats underwent unilateral ligation of the saphenous nerve.The portion of nerve tissues distal to the ligation site were harvested 1 week after operation.AASCs were isolated,cultured and purified.Spinal cord injury model produced in 42 Wistar rats on T7 by modified Allen impact method.Three days after injury,20 μl FSCS with a density of 1×105/μl prepared from pregnant rats (El4) in combination with AASCs were injected into the epicenter of the traumatized cavity.Animals were sacrificed at 2,4,6,8,10,12 weeks post transplantation.Light and electronmicroscopic studies as well as immunohistochemical assay were carried out to evaluate the graft survival,its differentation and integration with the host.ResultsIn the transplantation area,AASCs showed good growth and differentiation,and glial scarring surrounding the lesions was less.The neuroblast stretched out the terminal endings 4 weeks after implantation,followed by the presenting of the pre- and post-synaptic membrane.Eight weeks post transplantation,the dense or developed projections were observed in the pre- and post-synaptic membrane,the high electron dense substance full filled the synaptic cleft.All the spherical cleat vesicles,granular vesicles,elliptical vesicles and flattened-f type vesicles were discovered under the electron microscope.Ten weeks after injury,the axosomatic,dendrosomatic,dendro-dendritic,axoaxonic,and dendro-axonic synapses coexisted.Light microscopy showed that the graft cell grew gradually.Immunohistochemical assay showed that NF,5-HT,CGRP and GFAP positive fibers were in the graft.Synapses,glia fibers and blood brain barrier integrated each other.Conclusion1) The transplanted FSCS combined with AASCs can develop mature synapses with miscellaneous synaptic vesicles in the acute injured spinal cord.2) Co-existing indicate the possibility of synaptic connection between FSCS and host.