Abstract: Objective To investigate the effects of PRF on mandibular distraction osteogenesis and the expression of BMP-6 in the period of distraction osteogenesis. Methods Twenty-five mature rabbits were randomly divided into five groups, Mandibular osteotomies were performed corticectomy in bilateral mature rabbits,PRF were implanted in the one side of mandibles as experimental group. Another side of madibular as control group,The rabbits were sacrificed and the distracted calluses were harvested and processed for HE and BMP-6 immunohistochemistry on the 1st,3th,7th,14st and 28th day after the end of distraction, respectively.The expressions of BMP-6 in the distracted calluses were analyzed by cell digital imaging software. Results The regenerated bone was found in the distraction gap after mandibular lengthening.BMP-6 were co-localized in cytoplasm of osteoblasts and newly embedded osteocytes.Compared with control group, the positive cell rate and positive area percentage of BMP-6 were higher on the 1st, 3th and 7th day after the distraction in experimental group(P＜0.05).Then there was no statistical significance on the positive cell rate and positive area percentage of BMP-6 on the 14st and 28th day after the distraction in experimental group.Conclusion? PRF could accelerate bone formation of mandibular distraction osteogenesis in rabbit,BMP-6 may play important roles at the early stage of mandibular distraction.

Key words: bone morphogenetic proteins, osteogenesis,distraction, rabbits, platelet-rich fibrin, bone morphogenetic protein 6