P>Objective To investigate the expressions of HIF-1α, c-fos and their relationships in mandibular distraction osteogenesis in rabbits. Methods To establish an animal model of mandibular distraction osteogenesis with 25 healthy adult rabbits.The expressions of HIF-1α and EM>c-fos/EM> were detected by ultrasensitive SP immunohistochemical methods. Results Immunohistochemical studies showed that the HIF-1α was expressed strongly in distraction zone at the 8th days after distraction. One week after consolidation, the EM>c/EM>-EM>fos/EM> was expressed strongly in the distraction zone at the 4 th day, 8th days after distraction, and 1 week after consolidation.Both apparently expressed apparently higher than those in the distraction zone of at the third and fifth week after consolidation. HIF-1α and EM>c-fos/EM> were mainly expressed in fibroblasts, osteoblasts and osteocytes. Conclusion In mandibular distraction osteogenesis of rabbits, there is a marked relati