New bone formation in a true bone ceramic scaffold loaded with desferrioxamine in the treatment of segmental bone defect: a preliminary study

Desferrioxamine (DFO), an iron chelator, can stimulate osteogenesis and angiogenesis by stabilizing hypoxia-inducible factor 1 alpha. We postulate that a bone graft substitute combined with DFO is beneficial to the reconstruction of bone defects. We implanted pure true bone ceramic (TBC) and DFO-loaded TBC (DFO/TBC) scaffolds into 15-mm rabbit radial defects for 8 weeks. The bone segments were examined with X-ray, micro-CT and histology. Radiographs showed that the DFO/TBC scaffold became radiopaque, and the gaps between the scaffold and radial cut ends were often invisible. Variables from micro-CT, including the bone volume fraction (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N), were significantly increased in pure TBC and DFO/TBC scaffolds that had been implanted for 8 weeks compared to unimplanted TBC scaffolds (p values < 0.05-0.001). Between the former two groups, BV/TV and Tb.Th were significantly increased in DFO/TBC scaffolds (p < 0.001), but Tb.N did not show significant differences. Histological examinations showed considerably increased new bone and decreased TBC trabecular remnants in DFO/TBC scaffolds compared to pure TBC scaffolds. Many cavities in the new bone area in DFO/TBC scaffolds were occupied by bone marrow elements and blood vessels. Percent of new bone with tetracycline labeling was significantly greater in DFO/TBC scaffolds than in pure TBC scaffolds (p < 0.001). This preliminary study reveals that DFO can effectively induce new bone growing into TBC scaffolds, suggesting that the DFO/TBC composite is a promising bone graft substitute for the treatment of bone defects.