Proto-oncogene expression during fracture repair

The possibility that proto-oncogenes play a role in fracture repair has bee n investigated in this study. Closed fractures were created in the tibiae o f NZW rabbits and treated with a plaster cast. At intervals of 1 and 2 week s, sections of the fracture callus were obtained and stained using an immun ocytochemical technique which localised c-myc and c-jun. Osteogenic cells o f the periosteum, endosteum, Haversian canal and new bone trabeculae expres sed proto-oncogenes while hypertrophic chondrocytes were generally immunore active negative. The results suggest that proto-oncogene expression may be involved in post-fracture osteogenesis but not in the chondrogenic processe s which precede endochondral bone formation. This could be used as a tool f or diagnosing slow healing in the early stages of fracture repair. (C) 2000 Elsevier Science Ltd. All rights reserved.