VEGF enhances bone regeneration in critical size bone defects

Objective: Rat, with an 8 mm in diameter bone defect is called a critical size defect (CSD) because it does not heal completely on its own. Sixteen weeks after surgical creation of the defect, still the central portion does not show bone. We hypothesized that by stimulating the vascularization of the bone defect by implanting sponge with 1200ng in 120µL VEGF, bone CSD will heal.

Methods: Each rat was anesthetized and calvarial bone defects were created by an 8 mm trephine. Fifteen adult male rats were divided into three equal groups. All defects were covered by two Millipore filters, one under the periosteum and one above the dura. Group I served as negative controls with just the membranes. Group II was grafted with autologous bone (positive control). Group III were grafted with a sponge and VEGF. The calvaria were processed for evaluation with micro CT scan and subsequent histomorphometry using decalcified and H & E stained sections.

Results: The percentage surface area of the defects covered with bone (Aa), volume fraction of bone (Vv), material, and radiographic densities were the highest in the autologous bone group, followed by the VEGF group, and the least was the negative control group. The differences were all statistically significant (P<0.05).

Conclusion: The results confirm our hypothesis that vascularization of critical size bone defects using VEGF would enhance bone regeneration and the filling of CSD.