Abstract:Objective To investigate the effect of platelet-rich fibrin (PRF) on mandibular osteogenesis and the expression of osteoprotegerin (OPG) in the period of distraction osteogenesis. Methods Twenty-five mature rabbits were randomly divided into five groups, bilateral mandibular osteotomies were performed in the rabbits.PRF was implanted in one side of the mandible as experimental group. The other side of madible was taken as control group. The rabbits were sacrificed and the distracted calluses were harvested and processed for HE and OPG immunohistochemical staining on the 1st, 3th, 7th, 14th and 28th day after the end of distraction. The expression of OPG in the calluses was analyzed by cell digital imaging soft-ware. Results The regenerated bone was found in the distraction gap after mandibular lengthening, OPG was co-localized in cytoplasm of osteoblasts and newly-embedded osteocytes. Compared with the control group, the OPG-positive cell number was statistically different in the experimental group on the 1st, 3th, 7th, 14th and 28th day after distraction (P < 0.05). Conclusions Our preliminary result demonstrated that PRF increases new bone formation and has a positive effect on early bone healing. OPG may play important roles at the early stage of mandibular distraction.