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 gro wth factor-2 on the healing of segmental bone defects were evaluated in rab bits. One month after the external fixator originally designed for this exp eriment was installed in the tibia of the rabbit, a 3-mm bone defect was cr eated by an osteotomy in the middle of the tibia and 0, 50, 100, 200, or 40 0 mu g of fibroblast growth factor-2 in 100 mu l of saline solution was inj ected 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 ma nner with significant effects at concentrations of 100 mu g or greater. The se significant effects were observed at 5 weeks and later. One hundred micr ograms of the growth factor increased the volume and mineral content of new ly made bone by 95 and 36%, respectively, at 5 weeks. These results indicat e that a single local injection of fibroblast growth factor-2 stimulates th e healing of segmental defects. We speculate that such an injection could b e clinically useful for the healing of fractures even when the fracture gap is rather large.