Effects of Bone-Marrow–Derived MSC Transplantation on Functional Recovery in a Rat Model of Spinal Cord Injury: Comparisons of Transplant Locations and Cell Concentrations

Spinal cord injury (SCI) is a widely disabling condition, constraining those affected by it to wheelchairs and requiring intense daily care and assistance. Cell replacement therapies, targeting regeneration of cells in the injured cord, are currently gaining momentum in the field of SCI research. Previous studies indicate that mesenchymal stem cells (MSCs) can reduce functional deficits through immunomodulation and production of trophic factors in a variety of neurological disorders. The present study assessed the efficacy of transplanted bone marrow–derived MSCs at different concentrations and locations for promoting functional recovery following SCI. Although effects were modest, MSCs facilitated an increase in the base of support, as measured by increased distance between the plantar surface of the hind paws, following incomplete contusive SCI, and reduced the density of astroglial scarring. Varying the concentrations or locations of transplanted cells did not provide additional benefits on these measures. These findings indicate that MSC transplants are safe at relatively high concentrations and confer therapeutic benefits that, when used as an adjunctive treatment, could significantly enhance functional recovery following SCI.