The effect of fibroblast growth factor-2 on the osteoinductive activity of recombinant human bone morphogenetic protein-2 in rat muscle

To clarify the effect of recombinant human basic fibroblast growth factor (FGF-2) on the osteoinductive activity of recombinant human bone morphogenetic protein-2 (BMP-2) in vivo, different amounts of FGF-2 (0, 16, 80 and 400 ng, and 2, 10 and 50 micro g: n=10 in each group), BMP-2 (2 micro g) and type I collagen as a carrier were mixed and implanted into rat calf muscles. Three weeks after implantation, compared with the controls, the radiopaque shadows of the implants were increased in the 16, 80 and 400 ng FGF-2-treated groups, but decreased in the 2, 10 and 50 micro g FGF-2-treated groups. In addition, alkaline phosphatase activity was increased in the 16, 80 and 400 ng FGF-2-treated groups but decreased in the 50 micro g FGF-2-treated group. Histological examination revealed increased bone formation in the 16, 80 and 400 ng FGF-2-treated groups. These results show that combined treatment with FGF-2 and BMP-2 has a biphasic effect on osteoinductive activity, i.e. it increases with low doses of FGF-2 and decreases with high doses of FGF-2.