title: Treatment of irradiated mandibles with mesenchymal stem cells transfected with bone morphogenetic protein 2/7.
abstract: OBJECTIVE
  The study aimed to evaluate whether mesenchymal stem cells transfected with bone morphogenetic protein (BMP) 2/7 could increase bone regeneration after radiotherapy using a rabbit model of mandibular distraction osteogenesis.
  
  
  METHODS
  Twelve rabbits were randomly assigned to the sham control, radiotherapy control, nontransfected mesenchymal stem cells (MSCs), and MSCs transfected with BMP-2/7 groups. All rabbits, except those in the sham control group, received preoperative radiation of 9 Gy for 5 fractions. One month after radiotherapy, all rabbits underwent unilateral mandibular distraction at a rate of 0.9 mm/d for 11 days. At the end of active distraction, MSCs combined with bovine collagen were injected into the distraction zone. After 4 weeks of consolidation, the mandibular samples were collected and subjected to radiographic, microcomputed tomographic, and histologic examinations.
  
  
  RESULTS
  By radiographic examination, animals injected with nontransfected MSCs or MSCs encoding BMP-2/7 exhibited more bone formation than the control groups. Histologic examination showed that the group with MSCs encoding BMP-2/7 had a more mature medullary cavity than the nontransfected MSCs group.
  
  
  CONCLUSIONS
  MSCs encoding BMP-2/7 can increase bone healing in irradiated mandibular bone.
authors.affiliation: Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Hong Kong, Hong Kong.
authors.forename: Wen Biao
authors.initials: WB
authors.lastname: Zhang
authors.forename: Li Wu
authors.initials: LW
authors.lastname: Zheng
authors.forename: Daniel Tsin Tien
authors.initials: DT
authors.lastname: Chua
authors.forename: Lim Kwong
authors.initials: LK
authors.lastname: Cheung
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology; D001853:Bone Marrow / Q000473:pathology; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics*; D055419:Bone Morphogenetic Protein 7 / Q000235:genetics*; D001861:Bone Regeneration / Q000502:physiology*; D002417:Cattle; D018929:Cell Culture Techniques; D003094:Collagen; D008334:Mandible / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000201:enzymology*; D023421:Models, Animal; D010012:Osteogenesis / Q000502:physiology; D019857:Osteogenesis, Distraction; D010027:Osteotomy; D010957:Plasmids / Q000235:genetics; D011817:Rabbits; D011879:Radiotherapy Dosage; D011897:Random Allocation; D054457:Tissue Scaffolds; D014162:Transfection; D055114:X-Ray Microtomography
chemical_list: D055396:Bone Morphogenetic Protein 2; D055419:Bone Morphogenetic Protein 7; D003094:Collagen