Continuous Administration of Basic Fibroblast Growth Factor (FGF-2) Accelerates Bone Induction on Rat Calvaria— An Application of a New Drug Delivery System

Some studies have shown that locally applied basic fibroblast growth factor (FGF-2) enhances bone regeneration at a fracture site, while others have not been in agreement. We developed a new continuous FGF-2 delivery system designed to accelerate cytokine-induced new bone formation. A subperiosteal pocket was surgically formed in 36 eight-week-old male Wistar rats. The rats were administered 0, 1, 10, or 100 ng of FGF-2 contained in a collagen minipellet, mixed with allogeneic demineralized bone matrix in a dome-shaped Millipore filter and then placed into the pocket. New bone formation in the dome was evaluated at 2, 4, and 8 wks after placement. Soft x-ray radiographs disclosed an apparently larger radiopaque region in the 1-ng group at 4 wks compared with those in the other groups. Morphometrical analysis revealed that the new bone area in the 1-g group was significantly larger than that in the 0-g group (p<0.01). In the 100-ng FGF-2 group, new bone formation seemed suppressed. We concluded that continuous slow administration of a small amount of FGF-2 accelerates bone-derived osteogenic cytokine-induced new bone formation.