title: Targeting gene expression during the early bone healing period in the mandible: A base for bone tissue engineering.
abstract: OBJECTIVE
  Although bone tissue engineering techniques have become more and more sophisticated than in the past, natural bone healing mechanisms have not been sufficiently considered for further improvement of these techniques so far. We used an established animal model with transcriptome analysis to generate an unbiased picture of early bone healing to support tissue engineering concepts.
  
  
  METHODS
  In 30 Wistar rats, a 3-mm bone defect was created in the mandibular angle. Tissue was sampled at 5, 10, and 15 days, and the former defect area was excised to undergo transcriptome analysis after RNA extraction. Five differentially expressed genes were further evaluated with reverse transcription-polymerase chain reaction (rt-PCR).
  
  
  RESULTS
  Transcriptome analysis revealed 2467 significantly over- and under-expressed transcripts after 5 days and 2265 after 15 days of bone healing, respectively. Validation via rt-PCR confirmed overexpression of osteoactivin, angiopoietin-like factor-4, and metallomatrix proteinase-9 and underexpression of mastcellprotease-10 and proteoglycane-2 in comparison to values in the control group.
  
  
  CONCLUSIONS
  This systematic genome-wide transcriptome analysis helps to decipher the physiological mechanisms behind physiological bone healing. The exemplary depiction of 5 genes demonstrates the great complexity of metabolic processes during early bone healing. Here, BMP-2 signaling pathways and local hypoxia play decisive roles in bone formation.
authors.affiliation: University Medical Center Hamburg-Eppendorf, Department of Oral and Maxillofacial Surgery, Martinistraße 52, Campus Forschung Gebäude N27, 20246 Hamburg, Germany. Electronic address: b.beck-broichsitter@uke.de.
authors.forename: Benedicta E
authors.initials: BE
authors.lastname: Beck-Broichsitter
authors.affiliation: Schleswig-Holstein University Hospital, Institute of Clinical and Experimental Pharmacology, Arnold-Heller-Straße 3, Haus 30, 24105 Kiel, Germany.
authors.forename: Anneke N
authors.initials: AN
authors.lastname: Werk
authors.affiliation: University Medical Center Hamburg-Eppendorf, Department of Oral and Maxillofacial Surgery, Martinistraße 52, Campus Forschung Gebäude N27, 20246 Hamburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Smeets
authors.affiliation: University Medical Center Hamburg-Eppendorf, Department of Oral and Maxillofacial Surgery, Martinistraße 52, Campus Forschung Gebäude N27, 20246 Hamburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Gröbe
authors.affiliation: University Medical Center Hamburg-Eppendorf, Department of Oral and Maxillofacial Surgery, Martinistraße 52, Campus Forschung Gebäude N27, 20246 Hamburg, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Heiland
authors.affiliation: Schleswig-Holstein University Hospital, Institute of Clinical and Experimental Pharmacology, Arnold-Heller-Straße 3, Haus 30, 24105 Kiel, Germany.
authors.forename: Ingolf
authors.initials: I
authors.lastname: Cascorbi
authors.affiliation: Schleswig-Holstein University Hospital, Department of Oral and Maxillofacial Surgery (Head: J. Wiltfang, MD, DMD, PhD), Arnold-Heller-Straße 3, Haus 26, 24105 Kiel, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Wiltfang
authors.affiliation: Institute of Clinical Molecular Biology, Center for Molecular Biosciences, Christian Albrechts University of Kiel, Am Botanischen Garten 11, 24118 Kiel, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Häsler
authors.affiliation: Schleswig-Holstein University Hospital, Department of Oral and Maxillofacial Surgery (Head: J. Wiltfang, MD, DMD, PhD), Arnold-Heller-Straße 3, Haus 26, 24105 Kiel, Germany.
authors.forename: Stephan T
authors.initials: ST
authors.lastname: Becker
mesh_terms: D000075803:Angiopoietin-Like Protein 4; D042682:Angiopoietins / Q000235:genetics; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics; D015687:Cell Hypoxia / Q000235:genetics; D058575:Decorin / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods*; D005786:Gene Expression Regulation / Q000235:genetics; D055106:Genome-Wide Association Study; D008334:Mandible / Q000502:physiology* / Q000601:surgery; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics; D023421:Models, Animal; D010012:Osteogenesis / Q000235:genetics*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012697:Serine Endopeptidases / Q000235:genetics; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D014945:Wound Healing / Q000235:genetics
chemical_list: C528241:ANGPTL4 protein, rat; D000075803:Angiopoietin-Like Protein 4; D042682:Angiopoietins; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D058575:Decorin; C503043:Gpnmb protein, rat; D008562:Membrane Glycoproteins; D012697:Serine Endopeptidases; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat
keywords: Animal model; Bone tissue engineering; Physiological bone healing; Transcriptome profiling; rat; rt-PCR