title: Action of recombinant human BMP-2 on fracture healing in rabbits is dependent on the mechanical environment.
abstract: The utility of recombinant human bone morphogenetic protein-2 (rhBMP-2) in inducing bone formation in fractures of bone is well known. However, the influence of the mechanical environment on the actions of rhBMP-2 on fracture healing is not clear. An experimental model of fractures of the tibia in rabbits was developed and utilized to investigate the role of mechanical environment on rhBMP-2 action. A 1 mm osteotomy gap was stabilized by either a low- or high-stiffness fixator (LSF or HSF, respectively), and local treatment with rhBMP-2 in an absorbable collagen sponge (ACS) was evaluated. The results of the investigation were analysed by both histomorphometry and biomechanics. The LSF caused an increase in mineralized periosteal callus compared to HSF, the rhBMP-2 in ACS accelerated fracture healing only in the LSF group but not in the HSF group. The area of mineralized tissue in interfragmentary callus was determined by fixation stiffness and not by BMP treatment. rhBMP-2 caused higher bone resorption in the endosteal callus during the late stages of fracture healing, but these histological differences did not affect the mechanical properties. Biomechanical evaluation showed only differences at 3 weeks between LSF-rhBMP-2 and LSF-ACS. The bending and torsional properties were higher in the rhBMP-2/ACS group compared to ACS alone at 3 weeks.
authors.affiliation: Department of Cell Biology, Genetics and Physiology, Faculty of Sciences, University of Málaga, Málaga, Spain.
authors.forename: María D
authors.initials: MD
authors.lastname: Cuenca-López
authors.forename: José L
authors.initials: JL
authors.lastname: Peris
authors.forename: Mireia
authors.initials: M
authors.lastname: García-Roselló
authors.forename: Carlos
authors.initials: C
authors.lastname: Atienza
authors.forename: Jaime
authors.initials: J
authors.lastname: Prat
authors.forename: José
authors.initials: J
authors.lastname: Becerra
authors.forename: José A
authors.initials: JA
authors.lastname: Andrades
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects; D002146:Bony Callus / Q000378:metabolism; D002113:Calcification, Physiologic / Q000187:drug effects*; D003094:Collagen / Q000494:pharmacology*; D017102:Fracture Healing / Q000187:drug effects*; D006801:Humans; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology*; D013978:Tibial Fractures / Q000188:drug therapy*; D013997:Time Factors
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; D003094:Collagen