Chitosan Channels Containing Spinal Cord-Derived Stem/Progenitor Cells for Repair of Subacute Spinal Cord Injury in the Rat

OBJECTIVE: We evaluated the survival and differentiation capacity of neural stem/progenitor cells (NSPCs) derived from the adult rat spinal cord and seeded on intramedullary chitosan channels that were implanted in a subacute rat spinal cord injury model. METHODS: We implanted into the injured spinal cord a chitosan channel filled with NSPCs harvested from the spinal cord of adult transgenic rats expressing green fluorescent protein 3 weeks after extradural 35g clip compression injury at T8. The NSPC-chitosan channel group was compared with 2 control groups not receiving channels: 1 receiving a direct intramedullary injection of NSPCs into the lesion cavity and 1 receiving trauma alone. The survival and differentiation of NSPCs were evaluated with immunohistochemical and histopathological techniques, and functional improvement was assessed for 6 weeks with the Basso, Beattie, and Bresnahan locomotor score. RESULTS: The NSPC-chitosan channel group showed enhanced survival of NSPCs compared with NSPCs transplanted directly into the lesion cavity, although there was no significant difference in functional recovery between the treatment and control groups. In addition, the intramedullary implantation of the chitosan channel did not worsen the functional deficit after the 35g clip injury. CONCLUSIONS: Chitosan channels enhanced the survival of transplanted NSPCs in the subacutely injured spinal cord. Functional deficits were not exacerbated by the intramedullary transplantation of chitosan channels into the site of injury.