Natural bone collagen scaffold combined with OP-1 for bone formation induction in vivo

The scaffold is a key element to osteogenic tissue engineering as it provides amicroenvironment for bone formation. Natural bone collagen scaffold (NBCS) is a novelbiomaterial scaffold acid-extracted from organic human bone. The objective of this studywas to characterize NBCS and evaluate the osteoconductivity of the scaffold, in combinationwith osteogenic protein-1 (OP-1), using a rabbit posteolateral lumbar fusion model. Thirtytwo rabbits were divided into 4 experimental groups, autograft, NBCS alone, OP-1 alone orNBCS combined with OP-1. Bone formation was evaluated by micro-CT, quantitativehistological analysis, immunohistochemistry and semi-quantitative RT-PCR at 6 weekspostoperatively. By scanning electronic microscope, we showed that NBCS maintains aporous, interconnecting microarchitecture. Micro-CT analysis demonstrated that NBCScombined with OP-1 significantly induced (p <0.01) bone formation at the fusion site ascompared to control groups. This was confirmed by quantitative histological analysis whichdemonstrated that the NBCS combined with OP-1 significantly enhanced bone matrix area(17.7 mm2) (p <0.05) and bone marrow cavity size (71.3 mm2) (p <0.05) as compared to thecontrols. Immunohistochemical assessment and RT-PCR also demonstrated that NBCScombined with OP-1 enhanced type I collagen and osteonectin expression. Together, theseresults suggest that NBCS is an effective scaffold for osteogenesis, and combined with growthfactors such as OP-1, possesses both osteoconductive and osteoinductive properties that aresufficient for bone regeneration. ' 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: ApplBiomater 90B: 778–788, 2009