Proto-oncogene expression during fracture repair

The possibility that proto-oncogenes play a role in fracture repair has been investigated in this study. Closed fractures were created in the tibiae of NZW rabbits and treated with a plaster cast. At intervals of 1 and 2 weeks, sections of the fracture callus were obtained and stained using an immunocytochemical technique which localised c-myc and c-jun. Osteogenic cells of the periosteum, endosteum, Haversian canal and new bone trabeculae expressed proto-oncogenes while hypertrophic chondrocytes were generally immunoreactive negative. The results suggest that proto-oncogene expression may be involved in post-fracture osteogenesis but not in the chondrogenic processes which precede endochondral bone formation. This could be used as a tool for diagnosing slow healing in the early stages of fracture repair.