Survival of transplanted neural stem/progenitor cells (NSPC) is limited after spinal cord injury (SCI). This project tested whether ephrin-B3 could enhance the survival of spinal cord derived NSPC based on the report that ephrin-B3 enhanced the survival of endogenous NSPC in the mouse brain. Preclustered ephrin-B3-Fc was tested, and preclustered Fc fragments and phosphate-buffered saline (PBS) were used as controls. This study showed that spinal cord derived NSPC and normal and injured rat spinal cord expressed EphA4 receptors. In culture, ephrin-B3-Fc increased the survival of NSPC at 1mug/mL (p<0.05), but Fc fragments reduced NSPC survival dose-dependently. In the injured spinal cord, infusion of ephrin-B3-Fc increased the proliferation of endogenous ependymal cells compared with infusion of PBS (p<0.05). However, in the injured cord, infusion of either ephrin-B3-Fc or Fc fragments caused a 20-fold reduction in the survival of transplanted NSPC (p<0.001). Thus, after SCI, ephrin-B3-Fc and Fc fragments are toxic to transplanted NSPC. |