Single local injection of recombinant fibroblast growth factor-2 stimulates healing of segmental bone defects in rabbits.

The effects of a single local injection of recombinant human fibroblast growth factor-2 on the healing of segmental bone defects were evaluated in rabbits. One month after the external fixator originally designed for this experiment was installed in the tibia of the rabbit, a 3-mm bone defect was created by an osteotomy in the middle of the tibia and 0, 50, 100, 200, or 400 microg of fibroblast growth factor-2 in 100 microl of saline solution was injected into the defect. Injection of the growth factor increased the volume and mineral content of newly made bone at the defect in a dose-dependent manner with significant effects at concentrations of 100 microg or greater. These significant effects were observed at 5 weeks and later. One hundred micrograms of the growth factor increased the volume and mineral content of newly made bone by 95 and 36%, respectively, at 5 weeks. These results indicate that a single local injection of fibroblast growth factor-2 stimulates the healing of segmental defects. We speculate that such an injection could be clinically useful for the healing of fractures even when the fracture gap is rather large.