O'Donovan D A, Yeung I, Zeman V, Neligan P C, Pang C Y, Forrest C R
Division of Plastic Surgery, The Hospital for Sick Children Center for Craniofacial Care and Research, University Health Network, University of Toronto, Toronto, Ontario, Canada.
J Craniofac Surg. 2001 Nov;12(6):533-43. doi: 10.1097/00001665-200111000-00006.
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.
因治疗性放射导致的骨生长抑制所引起的颅面畸形，在儿童头颈癌幸存者中发生率可达100%。放射诱导颅面骨生长抑制的机制目前尚不清楚。本研究的目的是建立一个放射诱导颅面骨生长抑制模型，以研究放射对生长中的膜性骨的病理生理学影响。将7周龄雄性新西兰白兔随机分为4组（每组n = 10只），对其右侧眶颧复合体给予单次剂量的深部X线照射（0、15、25或35 Gy）。在21周骨骼成熟前，定期进行X线片和计算机断层扫描，以进行头影测量分析、骨体积和骨密度测量。与未照射的对照动物相比，25或35 Gy照射后，眶颧复合体的线性骨生长、骨体积和骨密度出现具有统计学意义（P < 0.05）的降低。15 Gy照射后，眶颧复合体体积出现显著（P < 0.05）减小，但在此剂量下，通过头影测量分析评估，对线性骨生长没有显著影响。本研究将兔眶颧复合体确立为研究放射诱导颅面骨生长抑制的合适模型，并将有助于探究这种损伤的潜在细胞和分子基础。
