FGF-2-responsive and spinal cord-resident cells improve locomotor function after spinal cord injury

The adult central nervous system has only a limited capacity for axonal regeneration. In this study, fibroblast growth factor-2 (FGF-2) was injected once into the spinal cord tissue around the injury site immediately after complete spinal cord transection in rats. This treatment markedly improved the locomotor function of the animals. Histological analysis demonstrated that tissue composed of FGF-2-induced fibronectin-positive cells (FIFs) had infiltrated the injury site and filled large cystic cavities, into which numerous axons with growth-associated protein-43 immunoreactivity penetrated. The FIFs could also be cultured from the intact spinal cord tissue, demonstrating that they were resident in the non-injured spinal cord. They had a spindle-shaped morphology and enhanced expression of mRNAs of N-cadherin and neurotrophic factors, suggesting the beneficial properties of the FIFs for axonal regeneration. Thus, these results argue for the continual use of autologous transplantation as a novel and promising cell therapy for the treatment of spinal cord injury.