title: Radiomorphometry and biomechanical assessment of recombinant human bone morphogenetic protein 2 and polymer in rabbit radius ostectomy model.
abstract: The study objective was to determine the mechanical integrity and radiopacity of regenerated bone within critical-sized defects (CSDs) in radii of rabbits using recombinant human bone morphogenetic protein 2 (rhBMP-2) with a porous, biodegradable poly(D,L-lactic acid) (PDLLA) carrier (designated PLA). Twenty millimeter, unilateral radial ostectomies were created in 96 skeletally mature New Zealand white rabbits. The rabbits were randomly assigned to six treatment groups with two euthanasia periods. Treatment groups included unfilled defect (n = 8), segmental autograft (n = 8), PLA + 0 microg rhBMP-2 (n = 8), PLA + 17 microg rhBMP-2 (n = 8), PLA + 35 microg rhBMP-2 (n = 8), and PLA + 70 microg rhBMP-2 (n = 8). The radiopacity was significantly greater for the 35- and 70-microg rhBMP-2 groups at 4 weeks compared to unfilled controls, PLA only, and 17-microg rhBMP-2 groups and equivalent to the autograft. At 8 weeks all groups receiving rhBMP-2 were equivalent to the autograft and significantly greater than unfilled defects and PLA alone. Similarly, the biomechanical analysis indicated significantly greater torque at failure for the 35-microg rhBMP-2 group compared to all other groups at 4 weeks. By 8 weeks all groups receiving rhBMP-2 and autograft had significantly greater torque than unfilled controls and PLA alone. These radiomorphometric and biomechanical results indicate PLA may be a suitable carrier for rhBMP-2 used for skeletal regeneration.
authors.affiliation: University of Florida, Department of Orthopaedics, Gainesville 32610, USA. wheelerd@ortho.ufl.edu
authors.forename: D L
authors.initials: DL
authors.lastname: Wheeler
authors.forename: D L
authors.initials: DL
authors.lastname: Chamberland
authors.forename: J M
authors.initials: JM
authors.lastname: Schmitt
authors.forename: D C
authors.initials: DC
authors.lastname: Buck
authors.forename: J H
authors.initials: JH
authors.lastname: Brekke
authors.forename: J O
authors.initials: JO
authors.lastname: Hollinger
authors.forename: S P
authors.initials: SP
authors.lastname: Joh
authors.forename: K W
authors.initials: KW
authors.lastname: Suh
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D016025:Bone Transplantation / Q000502:physiology; D001842:Bone and Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000494:pharmacology; D011091:Polyesters; D011108:Polymers / Q000494:pharmacology*; D011817:Rabbits; D011859:Radiography; D011884:Radius / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D013997:Time Factors; D016212:Transforming Growth Factor beta
chemical_list: C525718:BMP2 protein, human; D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011091:Polyesters; D011108:Polymers; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D019344:Lactic Acid; C033616:poly(lactide)