title: Bone repair of critical size defects treated with autogenic, allogenic, or xenogenic bone grafts alone or in combination with rhBMP-2.
abstract: OBJECTIVE
  To evaluate the bone repair of critical size defects treated with autogenic, allogenic, or xenogenic bone grafts alone or in combination with rhBMP-2.
  
  
  METHODS
  In 112 rats, a critical bone defect of 5 mm bilaterally in the calvaria was made and filled with different bone grafts alone or combined with rhBMP-2: group autograft (AuG); group allograft (AlG); group xenograft (XeG); group AuG/BMP-2 (autograft and 5 μg rhBMP-2); group AlG/BMP-2 (allograft and 5 μg rhBMP-2); group XeG/BMP-2 (xenograft and 5 μg rhBMP-2); group BMP-2 (5 μg rhBMP-2); and control group, filled only with blood coagulum. After a period of 4 or 6 weeks, the animals were euthanized. Histological and histometric analyses were performed for new bone formation (NB), as well as the immunohistochemical detection of tartrate-resistant acid phosphatase (TRAP), and zymographic analysis (MMP) of type 2 and 9.
  
  
  RESULTS
  Histological analysis showed the bone healing process was faster and favorable in AuG and AuG/BMP-2. In both periods, the grafted groups (AuG, XeG and AlG) had a greater volume of NB than the control group, which was even greater when combined with rhBMP-2. The XeG group showed a higher number of TRAP-positive multinucleated osteoclasts, and enzymatic activity revealed different levels of proMMP-2, MMP-2, and MMP-9 (6 weeks).
  
  
  CONCLUSIONS
  The different types of grafts increased bone formation, mainly associated with rhBMP-2, enhancing and accelerating the repair process. These groups had higher enzymatic indices than the control group especially with XeG, which also showed higher TRAP-positive multinucleated cells similar to osteoclasts, suggesting a remodeling process.
authors.affiliation: Department of Morphology, Physiology and Basic Pathology, University of São Paulo, São Paulo, Brazil.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Issa
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor- School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors.forename: Miliane
authors.initials: M
authors.lastname: Gonzaga
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor- School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors.forename: Bruna Gabriela
authors.initials: BG
authors.lastname: Kotake
authors.affiliation: Department of Morphology, Physiology and Basic Pathology, University of São Paulo, São Paulo, Brazil.
authors.forename: Conrado
authors.initials: C
authors.lastname: de Lucia
authors.affiliation: Department of Basic Science at the School of Dentistry of Araçatuba, São Paulo State University, São Paulo, Brazil.
authors.forename: Edilson
authors.initials: E
authors.lastname: Ervolino
authors.affiliation: Department of Morphology, Physiology and Basic Pathology, Faculty of Dentistry, University of São Paulo, São Paulo, Brazil.
authors.forename: Mamie
authors.initials: M
authors.lastname: Iyomasa
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D016025:Bone Transplantation / Q000379:methods*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D010012:Osteogenesis; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D012886:Skull / Q000601:surgery*; D000071681:Tartrate-Resistant Acid Phosphatase / Q000378:metabolism
chemical_list: D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; D000071681:Tartrate-Resistant Acid Phosphatase; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat
keywords: animal experiments; bone substitutes; growth factors; morphometric analysis; wound healing