We examined the restorative effect of modiifed biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantationin vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial ifbrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve ifbers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our ifndings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvi-ronment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.