Abstract
The scaffold is a key element to osteogenic tissue engineering as it provides a microenvironment for bone formation. Natural bone collagen scaffold (NBCS) is a novel biomaterial scaffold acid‐extracted from organic human bone. The objective of this study was to characterize NBCS and evaluate the osteoconductivity of the scaffold, in combination with osteogenic protein‐1 (OP‐1), using a rabbit posteolateral lumbar fusion model. Thirty two rabbits were divided into 4 experimental groups, autograft, NBCS alone, OP‐1 alone or NBCS combined with OP‐1. Bone formation was evaluated by micro‐CT, quantitative histological analysis, immunohistochemistry and semi‐quantitative RT‐PCR at 6 weeks postoperatively. By scanning electronic microscope, we showed that NBCS maintains a porous, interconnecting microarchitecture. Micro‐CT analysis demonstrated that NBCS combined with OP‐1 significantly induced (p < 0.01) bone formation at the fusion site as compared to control groups. This was confirmed by quantitative histological analysis which demonstrated that the NBCS combined with OP‐1 significantly enhanced bone matrix area (17.7 mm^2^) (p < 0.05) and bone marrow cavity size (71.3 mm^2^) (p < 0.05) as compared to the controls. Immunohistochemical assessment and RT‐PCR also demonstrated that NBCS combined with OP‐1 enhanced type I collagen and osteonectin expression. Together, these results suggest that NBCS is an effective scaffold for osteogenesis, and combined with growth factors such as OP‐1, possesses both osteoconductive and osteoinductive properties that are sufficient for bone regeneration. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009