TGF-BETA-1 FORMS FUNCTIONALLY NORMAL BONE IN A SEGMENTAL SHEEP TIBIALDIAPHYSEAL DEFECT

Objective: Transforming growth factor-beta 1 (TGF-beta 1) is a polyfun ctional regulatory cytokine that has been shown to have roles in extra cellular matrix interactions, soft tissue healing, and osteogenesis. T his study was undertaken to determine the efficacy of TGF-beta 1 in th e formation of functionally normal bone in tibial-diaphyseal defects. Method: Seven hundred fifty micrograms of recombinant human TGF-beta 1 was added to a guanidine-extracted demineralised bone matrix (Gu-DBM) carrier and the implants were used to fill a 2.5 cm tibial diaphyseal defect in skeletally mature female sheep. The defects were allowed to heal over a 12-week period. After sacrifice, they were analyzed using four-point bending mechanical testing. Results: Implants with TGF-bet a 1 showed complete bony bridging of the defect and stress-strain curv es similar to the normal contralateral limb, while implants with the c arrier alone failed to bridge the gap. Conclusions: These results demo nstrate the ability of TGF-beta 1 to induce new bone which has structu ral and functional characteristics similar to normal bone.