Repair of lateral hemisection lesion in spinal cord using schwann cells differentiated from subcutaneous fat tissue delivered in fibrin plug

Previously, we showed that rat subcutaneous fat tissue comprises of nestin-expressing spheroids, which are efficiently induced to Schwann cells (SCs) in vitro under the inducing condition and display Schwann cell properties in vivo. In this study, we investigated whether induced SCs could be engaged in the repair of the lateral hemisection lesion of the rat spinal cord using PKH26-labeled cells and also tested the feasibility of fibrin glue as a cell delivery vehicle in the blunt gap lesion. At the end of twelve weeks after the transplantation, the lesion site was fully filled with the regenerated tissue, which contained PKH26-labeled cells and P0 expressing cells. Some of PKH26-labeled cells were shown as a hollow tube-like structure, which was co-localized with the P0 antigen. Several types of neurons were also detected in the regenerated tissue. Among them, a few GABAnergic interneuron, CGRP positive neurons, and serotonergic neurons were found at the hemisection lesion site, which were probably infiltrated to the lesion site from the surrounding normal tissue. However, in the control lesion which received fibrin glue only, the majority of lesion site was filled with connective tissue containing numerous fibroblasts and relatively fewer SCs and neurons compared to those in SCs treated group. Thus, the induced SCs delivered with fibrin glue survived at the lesion site in the spinal cord and engaged in the myelin sheath regeneration. Furthermore, SCs along with the fibrin glue, applied as a cell delivery vehicle, seem to provide permissive microenvironment for the active infiltration of host neural and glial cells from the uninjured neighboring tissue.