PDGF-BB Induces Formation of Bridging Callus After Reconstructive Surgery of Large Bone Defect

Reconstructive surgery by using allografts often conducted to manage large bone defects, either due to traumatic or non-traumatic causes. However, poor vascularization of the graft bed is still problematic. To overcome this, bone tissue engineering method has been developed that uses growth factor as an angiogenic stimulator, such as platelet derived growth factor BB (PDGF BB).

This study aimed to evaluate the administration of recombinant rat Platelet Derived Growth Factor BB (rrPDGF BB) on bone healing process, showed by formation of bridging callus, Vascular Endothelial Growth Factor (VEGF), Bone Morphogenetic Protein-2 (BMP-2) and osteocalcin in massive fresh frozen allograft post reconstructive surgery.

This was a Post Test Only Control Group Design study involved 32 Wistar rats divided into two groups, i.e. treatment group (defect on right femoral bone and received fresh frozen allograft with the addition of rrPDGF BB) and control group (without addition of rrPDGF BB). Expression of VEGF, BMP-2 and osteocalcin was identified through immunohistochemistry.

A significantly higher expression of VEGF, BMP-2 and osteocalcin was observed in the treatment group as compared to the control group (p < 0.05). The presence of bridging callus on the fresh frozen allograft also showed to be significant (p = 0.003). Path analysis showed formation of bridging callus after administration of PDGF on allograft occur through three pathways, in which VEGF holds the most important role.

The application of rrPDGF BB significantly enhances the formation of new bone through increased expression of VEGF, BMP-2 and osteocalcin.