Bone response and mechanical strength of rabbit femoral defects filled with injectable CaP cements containing TGF-ß1 loaded gelatin microparticles

This study focused at the potential of transforming growth factor ss 1 (TGF-ss 1) loaded gelatin microparticles to enhance the bone response and mechanical strength of rabbit femoral defects filled with injectable calcium phosphate (CaP)/gelatin microparticle composites. Therefore, TGF-ss 1 loaded composites and non-loaded controls were injected in circular defects as created in the femoral condyles of rabbits and were left in place for 4, 8 and 12 weeks. The specimens were evaluated mechanically (push-out test), and morphologically (scanning electron microscopy (SEM), histology, and histomorphometry). The results showed a gradual increase in mechanical strength with increasing implantation periods. Histological and histornorphometrical evaluation showed similar results for both composite formulations regarding histological aspect, new bone formation and bone/implant contact. However, TGF-ss 1 loading of the composites demonstrated a significant effect on composite degradation after twelve weeks of implantation. The results of this study showed that CaP/gelatin composites show excellent osteogenic properties and a rapid increase in mechanical strength. The addition of TGF-ss 1 significantly enhances the bone remodeling process. (c) 2007 Elsevier Ltd. All rights reserved.