Platelet-rich plasma (PRP) is a common therapy for acceleration of bone healing in orthopaedic and maxillofacial surgery. The beneficial effect of platelet-rich plasma gels and concentrates has been attributed to the platelet-associated synthesis and release of growth factors and cytokines that promote blood coagulation, tissue repair and the process of bone mineralization. Due to the current exclusive use of PRP in bone graft therapies, this study analyzed the effect of PRP in acceleration of bone fracture healing in thirty-two adult male Lewis rats. Following pinning and open fracture of right femurs normal saline (control) or PRP was applied to the fracture sites before wound closure. X-ray radiographic analysis of fractured femurs demonstrated a higher callus to cortex ratio in both four and eight week PRP groups compared to the saline control groups indicating acceleration of bone healing through enhanced callus formation. Three-point load bearing capabilities were similar in femur fractures of four week PRP and control groups, thus, were increased in the eight week PRP compared to the saline control group suggesting PRP-dependent acceleration of bone formation. Acceleration of bone formation was further confirmed by H&E staining that showed enhanced bone formation at the fracture site in the eight week PRP compared to the control group. In addition, immunohistochemistry demonstrated upregulation in TGF-beta and bone morphogenetic protein 2 (BMP-2) in both four and eight week PRP groups compared to the saline control group suggesting PRP-mediated increased inflammatory activity at the fracture site. In summary, our results demonstrate that PRP accelerates bone fracture healing of rat femurs through enhancement of inflammatory activity, promotion of callus formation and acceleration of bone formation; however, clinical studies are needed to confirm these findings in human bone fractures.
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