title: Development of an intramuscular xenograft model of canine osteosarcoma in mice for evaluation of the effects of radiation therapy.
abstract: OBJECTIVE
  To develop an IM xenograft model of canine osteosarcoma in mice for the purpose of evaluating effects of radiation therapy on tumors.
  
  
  METHODS
  27 athymic nude mice.
  
  
  METHODS
  Mice were randomly assigned to 1 of 3 groups of 9 mice each: no treatment (control group), radiation at 10 Gy, or radiation at 15 Gy. Each mouse received 5 x 10(5) highly metastasizing parent osteosarcoma cells injected into the left gastrocnemius muscle. Maximum tumor diameter was determined with a metric circles template to generate a tumor growth curve. Conscious mice were restrained in customized plastic jigs allowing local tumor irradiation. The behavior and development of the tumor xenograft were assessed via evaluations of the interval required for tumor-bearing limbs to reach diameters of 8 and 13 mm, extent of tumor vasculature, histomorphology of tumors, degree of tumor necrosis, and existence of pulmonary metastasis and clinical disease in affected mice.
  
  
  RESULTS
  Tumor-bearing limbs grew to a diameter of 8 mm (0.2-g tumor mass) in a mean +/- SEM interval of 7.0 +/- 0.2 days in all mice. Interval to grow from 8 to 13 mm was significantly prolonged for both radiation therapy groups, compared with that of the control group. Histologic evaluation revealed the induced tumors were highly vascular and had characteristics consistent with those of osteosarcoma. Pulmonary metastasis was not detected, and there was no significant difference in percentage of tumor necrosis between groups.
  
  
  CONCLUSIONS
  A reliable, repeatable, and easily produced IM xenograft model was developed for in vivo assessment of canine osteosarcoma.
authors.affiliation: Departments of Small Animal Clinical Sciences College of Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Alastair R
authors.initials: AR
authors.lastname: Coomer
authors.forename: James P
authors.initials: JP
authors.lastname: Farese
authors.forename: Rowan
authors.initials: R
authors.lastname: Milner
authors.forename: David
authors.initials: D
authors.lastname: Taylor
authors.forename: Marc E
authors.initials: ME
authors.lastname: Salute
authors.forename: Didier A
authors.initials: DA
authors.lastname: Rajon
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Bova
authors.forename: Dietmar W
authors.initials: DW
authors.lastname: Siemann
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000473:pathology / Q000532:radiotherapy / Q000662:veterinary*; D004195:Disease Models, Animal; D004283:Dog Diseases / Q000473:pathology* / Q000532:radiotherapy; D004285:Dogs; D007150:Immunohistochemistry / Q000662:veterinary; D053208:Kaplan-Meier Estimate; D051379:Mice; D008819:Mice, Nude; D012516:Osteosarcoma / Q000473:pathology / Q000532:radiotherapy / Q000662:veterinary*; D011897:Random Allocation; D013047:Specific Pathogen-Free Organisms; D014183:Transplantation, Heterologous / Q000473:pathology*; D023041:Xenograft Model Antitumor Assays / Q000379:methods*