OIC-A006-loaded true bone ceramic heals rabbit critical-sized segmental radial defect

It has been reported that OIC-A006, an osteogenically inducible compound, is able to promote osteogenesis in vitro and in vivo. In this study, we used a rabbit critical-sized segmental radial defect model (CSD) (15 mm) to analyse the osteogenic activity of OIC-A006 in non-cell-seeded tissue engineering bone substitutes. The scaffold carrier was bovine sintered bone "true bone ceramic (TBC)". OIC-A006 was delivered by PLGA (D,L-lactide-co-glycolide acid) microspheres. Drug-free PLGA microspheres and rhBMP-2-loaded PLGA microspheres were used as negative and positive control groups, respectively. Three kinds of composite were fabricated by coupling TBC, type-I collagen and the corresponding microspheres. The animals were randomly divided into 4 groups: (1) Group A: defect only, (2) group B:TBC/Collagen/drug-free-microspheres, (3) group C:TBC/Collagen/ OIC-A006-microspheres, (4) group D: TBC/Collagen/rhBMP-2-microspheres. The samples were analysed by histology, X-ray,microcomputed tomography (micro-CT), and biomechanical analyses. The results showed that OIC-A006 promoted bone regeneration to a remarkable extent. It is suggested that the application of OIC-A006 might be a valuable method in bone tissue engineering for healing large segmental defects of long bones. However, the biomechanical strength was a little inferior to that of BMPs.