title: An Athymic Rat Model for Mandibular Osteoradionecrosis Allowing for Direct Translation of Regenerative Treatments.
abstract: OBJECTIVE
  We aim to create a model of mandibular osteoradionecrosis in athymic rats. Athymic rats provide an immunosuppressed environment whereby human stem cells and biomaterials can be used to investigate regenerative solutions for osteoradionecrosis, bridging the gap between in vivo testing and clinical application.
  
  
  METHODS
  Prospective animal study.
  
  
  METHODS
  Academic otolaryngology department laboratory.
  
  
  METHODS
  After Institutional Animal Care and Use Committee approval, 10 athymic nude rats were divided into 2 groups. The experimental group (n = 6) underwent irradiation (20 Gy), while the control group (n = 4) underwent sham irradiation catheter placement only. All 10 rats underwent extraction of the second mandibular molar 7 days later. The rats were sacrificed 28 days after dental extraction, and their mandibles were harvested. The mandibles were examined with histologic analysis and bone volume analysis based on 3-dimensional micro-computed tomography.
  
  
  RESULTS
  All 10 rats survived the experiment period. Radiographic and histologic analysis revealed decreased bone formation in the experimental group compared with the control group. Jaw region volume ratio was 0.83 for the experimental group versus 0.97 in the control group (P = .003). The region-of-interest volume ratio was 0.75 in the experimental group and 0.97 in the control group (P = .005). Histologically, there were increased osteoclasts (P = .02) and decreased osteoblasts (P = .001) as well as increased fibrosis in the experimental group versus the control group.
  
  
  CONCLUSIONS
  Mandibular osteoradionecrosis can be effectively and reproducibly produced in an athymic rat model. This will allow further research to study regenerative medicine in an athymic rat model.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Jackson
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Voss
authors.affiliation: Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Zachary C
authors.initials: ZC
authors.lastname: Wilson
authors.affiliation: Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Remmes
authors.affiliation: Department of Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Stalboerger
authors.affiliation: Division of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Keeney
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Moore
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota, USA janus.jeffrey@mayo.edu.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Janus
mesh_terms: D000818:Animals; D008297:Male; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D008963:Molar / Q000601:surgery; D010025:Osteoradionecrosis / Q000000981:diagnostic imaging / Q000209:etiology*; D011446:Prospective Studies; D051381:Rats; D011923:Rats, Nude; D014057:Tomography, X-Ray Computed; D014081:Tooth Extraction
keywords: animal model; mandible; osteoradionecrosis; translational research