title: Radiation-induced craniofacial bone growth inhibition: development of an animal model.
abstract: Craniofacial deformities caused by therapeutic radiation-induced bone growth inhibition can occur in up to 100% of survivors of childhood head and neck cancers. The mechanism of radiation-induced craniofacial bone growth inhibition is poorly understood. The objective of this study is to establish a model of radiation-induced craniofacial bone growth inhibition to study the pathophysiology of radiation on growing membranous bone. Seven-week-old male New Zealand white rabbits were randomized into 4 groups (n = 10/group) and received a single dose of orthovoltage radiation (0, 15, 25, or 35 Gy) to the right orbital-zygomatic complex. Serial radiographs and computed tomography scans were performed for cephalometric analysis, bone volume, and bone density measurements until skeletal maturity at 21 weeks. Statistically significant ( P < 0.05) reductions in orbital-zygomatic complex linear bone growth, bone volume, and bone density were found after radiation with 25 or 35 Gy compared with nonirradiated control animals. A significant ( P < 0.05) decrease in orbital-zygomatic complex volume was noted after 15-Gy radiation but there were no significant effects on linear bone growth as assessed by cephalometric analysis at this dose. This study establishes the rabbit orbital-zygomatic complex as a suitable model for the study of radiation-induced craniofacial bone growth inhibition and will permit investigation into the underlying cellular and molecular basis of this injury.
authors.affiliation: Division of Plastic Surgery, The Hospital for Sick Children Center for Craniofacial Care and Research, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: D A
authors.initials: DA
authors.lastname: O'Donovan
authors.forename: I
authors.initials: I
authors.lastname: Yeung
authors.forename: V
authors.initials: V
authors.lastname: Zeman
authors.forename: P C
authors.initials: PC
authors.lastname: Neligan
authors.forename: C Y
authors.initials: CY
authors.lastname: Pang
authors.forename: C R
authors.initials: CR
authors.lastname: Forrest
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015519:Bone Density / Q000528:radiation effects; D002508:Cephalometry; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D007091:Image Processing, Computer-Assisted; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000254:growth & development / Q000528:radiation effects; D009777:Occipital Bone / Q000000981:diagnostic imaging / Q000254:growth & development / Q000528:radiation effects; D009915:Orbit / Q000000981:diagnostic imaging / Q000254:growth & development / Q000528:radiation effects*; D010159:Palate / Q000000981:diagnostic imaging / Q000254:growth & development / Q000528:radiation effects; D011817:Rabbits; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental / Q000503:physiopathology; D011897:Random Allocation; D012886:Skull / Q000000981:diagnostic imaging / Q000254:growth & development / Q000528:radiation effects; D019291:Skull Base / Q000000981:diagnostic imaging / Q000254:growth & development / Q000528:radiation effects; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed; D015050:Zygoma / Q000000981:diagnostic imaging / Q000254:growth & development / Q000528:radiation effects*