Comparative evaluation of heat-treated bone allograft combined with platelet rich plasma, recombinant human bone morphogenetic protein 2 and zoledronic acid: An experimental study on the histopathological and histomorphometric aspects of bone healing

Abstract Background The establishment of a reliable technique for promoting bone formation without resorting to autografts remains an unresolved challenge. Currently, platelet-rich plasma (PRP), bone morphogenetic protein (BMP), and bisphosphonates are under intense scrutiny for their potential clinical utility in such instances. Despite their widespread investigation, the effect of these agents on bone formation is still a matter of debate, and the observed variations in their efficacy are influenced by multiple factors, including the biomaterials employed. The aim of this research was to assess the impact of bone allograft combined with platelet rich plasma, recombinant human bone morphogenetic protein-2 (rhBMP-2), and zoledronic acid on bone formation in rabbit femur defects. Materials and methods A total of 96 rabbits were used, and femoral bone defects with a diameter of 5mm and depth of 10mm were created. The bone allografts used were prepared from femoral heads according to the Marburg system. The rabbits were divided into four groups: (1) bone allograft with PRP (AG + PRP), (2) bone allograft with rhBMP-2 5µg (AG + BMP-2), (3) bone allograft with zoledronic acid 5µg (AG + ZA), and (4) bone allograft only (AG) as the control group. Histopathological and histomorphometric analyses were performed to evaluate bone defect healing after 14, 30, and 60 days. Results The findings from the histomorphometric analysis showed that the new bone formation inside the bone allograft was significantly greater in the AG + PRP group compared to AG and AG + Zol groups after 14- and 30 days (p < 0.000). The use of bone allograft with rhBMP-2 induced higher bone formation compared to AG group on days 14 and 30 (p < 0,000), but excessive osteoclast activity was observed on day 60. The local co-administration of ZOL with heat-treated allograft inhibits allograft resorption as well as new bone formation in the bone defect at all periods. Conclusion In conclusion, the study demonstrated that PRP and rhBMP-2, combined with a Marburg bone allograft, can significantly promote bone formation in the early stage of bone defect healing.