Segmental bone regeneration using an rhBMP-2-loaded gelatin/nanohydroxyapatite/fibrin scaffold in a rabbit model

Biomaterials. 2009 Oct;30(31):6276-85. doi: 10.1016/j.biomaterials.2009.08.003. Epub 2009 Aug 15.

Abstract

We aimed to develop a hybrid scaffold with a porous structure and similar composition as natural bone for the controlled release of bone morphogenetic protein-2 (BMP-2) to enhance bone regeneration. We fabricated a gelatin/nanohydroxypatite (nHAP) scaffold by glutaraldehyde chemical cross-linking a gelatin aqueous solution with nHAP granules at a 5:1 ratio (v/w). Then, fibrin glue (FG) mixed with recombinant human BMP-2 (rhBMP-2) was infused into the gelatin/nHAP scaffold and lyophilized to develop an rhBMP-2-loaded gelatin/nHAP/FG scaffold. On scanning electron microscopy, the composite had a 3-D porous structure. The rhBMP-2 release kinetics from the hybrid scaffold was sustained and slow, and release of rhBMP-2 was complete at 40 days. Immunohistochemistry, azo-coupling and alizarin S-red staining were used to study in vitro differentiation of human bone-marrow mesenchymal cells (hBMSCs). Strong positive staining results confirmed that rhBMP-2 released from the scaffold could improve osteocalcin (OCN) and alkaline phosphatase (ALP) expression and calcium deposition formation. RT-PCR results showed significantly high mRNA expression of ALP and OCN in hBM-MSCs cultured on the gelatin/nHAP/FG scaffold with rhBMP-2. DNA assay demonstrated that the scaffold was noncytotoxic and could promote hBMSC proliferation from the components of the hybrid scaffold, not released rhBMP-2. The hybrid scaffolds were then used to repair critical-size segmental bone defects of rabbit radius. Gross specimen, X-ray, bone histomorphology and bone mineral density assay demonstrated that the rhBMP-2-loaded gelatin/nHAP/FG scaffold had good osteogenic capability and could repair the segmental bone defect completely in 12 weeks.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins / chemistry*
  • Bone Morphogenetic Proteins / genetics
  • Bone Morphogenetic Proteins / pharmacology*
  • Bone Regeneration / physiology*
  • Durapatite / chemistry*
  • Female
  • Fibrin / chemistry*
  • Gelatin / chemistry*
  • Humans
  • Kinetics
  • Male
  • Microscopy, Electron, Scanning
  • Rabbits
  • Recombinant Proteins / chemistry*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / pharmacology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tissue Engineering / methods*
  • Tissue Scaffolds / chemistry*
  • Transforming Growth Factor beta / chemistry*
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / pharmacology*

Substances

  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins
  • Recombinant Proteins
  • Transforming Growth Factor beta
  • recombinant human bone morphogenetic protein-2
  • Gelatin
  • Fibrin
  • Durapatite