Induction of new bone by basic FGF‐loaded porous carbonate apatite implants in femur defects in rats

Abstract

The aim of the present study was to investigate whether porous carbonate apatite (CA) containing basic FGF (bFGF) enhances bone augmentation as compared with porous CA alone. Thirty-six disc-shaped porous CA implants were inserted into femur defects in 36 Wister rats. Porous CA containing 0, 5, or 50 ng of bFGF was placed in the defect. Bone augmentation was evaluated radiographically using micro-CT and histologically by conventional staining at 2 and 12 weeks. At 2 weeks postoperatively, new bone was evident in the defect sites with porous CA containing either 5 or 50 ng of bFGF. The area of regenerated bone, however, was significantly higher with porous CA containing 5 ng of bFGF than with porous CA containing 50 ng. At 12 weeks postoperatively, no differences in new bone formation were seen between porous CA containing 5 and 50 ng bFGF. Porous CA containing bFGF, however, markedly increased the amount of bone newly formed as compared with porous CA without bFGF. Regardless of the implantation period, TRAP-positive cells were visible around the material, indicating that osteoclast-like cells were resorbing porous CA. In accordance with the evidence, bioresorption of the material increased over time: 6.3-7.8% at 2 weeks to 9.1-11.5% at 12 weeks. Porous CA is useful as a growth factor carrier and scaffold for bone augmentation.