title: Segmental bone regeneration using an rhBMP-2-loaded gelatin/nanohydroxyapatite/fibrin scaffold in a rabbit model.
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.
authors.affiliation: Department of Orthopedics, Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin 300211, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Liu
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
authors.forename: Xuezhong
authors.initials: X
authors.lastname: Tian
authors.forename: Geng
authors.initials: G
authors.lastname: Cui
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yang
authors.forename: Shunlu
authors.initials: S
authors.lastname: Yu
authors.forename: Guosheng
authors.initials: G
authors.lastname: Xing
authors.forename: Boxun
authors.initials: B
authors.lastname: Zhang
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D001861:Bone Regeneration / Q000502:physiology*; D017886:Durapatite / Q000737:chemistry*; D005260:Female; D005337:Fibrin / Q000737:chemistry*; D005780:Gelatin / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008297:Male; D008855:Microscopy, Electron, Scanning; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D016212:Transforming Growth Factor beta / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*
chemical_list: D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D005780:Gelatin; D005337:Fibrin; D017886:Durapatite