Fibrin-based tissue engineering scaffolds enhance neural fiber sprouting and delay the accumulation of reactive astrocytes at the lesion in a subacute model of spinal cord injury.

The purpose of this study was to evaluate the effects of fibrin scaffolds on subacute rat spinal cord injury (SCI). Long-Evans rats were anesthetized and underwent a dorsal hemisection injury; two weeks later, the injury site was re-exposed, scar tissue was removed, and a fibrin scaffold was implanted into the wound site. An effective method for fibrin scaffold implantation following subacute SCI was investigated based on the presence of fibrin within the lesion site and morphological analysis 1 week after implantation. Prepolymerized fibrin scaffolds were found to be present within the lesion site 1 week after treatment and were used for the remainder of the study. Fibrin scaffolds were then implanted for 2 and 4 weeks, after which spinal cords were harvested and evaluated using markers for neurons, astrocytes, and chondroitin sulfate proteoglycans. Compared with untreated control, the fibrin-treated group had significantly higher levels of neural fiber staining in the lesion site at 2 and 4 weeks after treatment, and the accumulation of glial fibrillary acidic protein (GFAP) positive reactive astrocytes surrounding the lesion was delayed. These results show that fibrin is conducive to regeneration and cellular migration and illustrate the advantage of using fibrin as a scaffold for drug delivery and cell-based therapies for SCI.