Zhang Wen Biao, Zheng Li Wu, Chua Denial, Cheung Lim Kwong
Department of Oral & Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong, People's Republic of China.
J Oral Maxillofac Surg. 2010 Nov;68(11):2802-9. doi: 10.1016/j.joms.2010.04.024. Epub 2010 Aug 19.
The study aimed to evaluate dosage-dependent effects of irradiation on bone regeneration and established a radiation-compromised rabbit model of mandibular distraction osteogenesis.
Twenty-three rabbits were divided randomly into 7 groups. Group A served as the control group, whereas experimental groups B, C, D, E, F, and G received preoperative irradiation at doses of 6.5, 7.0, 7.5, 8.0, 8.5, and 9.0 Gy, respectively, for 5 fractions. After 1 month, all rabbits underwent osteotomy and distraction osteogenesis with 7 days of latency, 11 days of active distraction at a rate of 0.9 mm/d, and 4 weeks of consolidation; rabbit mandibles were subsequently subjected to histologic, radiographic, and micro-computed tomography analysis.
With increasing doses of irradiation, bone regeneration was markedly hampered. Radiographically, the high-dose groups (8.5 and 9.0 Gy) presented obscure cortical lines. Histologically, in the 8.5- and 9.0-Gy groups, cortical bones were not completely formed, and in the medullary cavity, there existed a large amount of fibrous tissue.
Radiotherapy compromises bone regeneration during distraction osteogenesis, and the adverse effect is dose dependent.
本研究旨在评估辐射对骨再生的剂量依赖性影响，并建立辐射损伤的兔下颌骨牵张成骨模型。
23只兔子随机分为7组。A组为对照组，而实验组B、C、D、E、F和G分别接受6.5、7.0、7.5、8.0、8.5和9.0 Gy的术前放疗，分5次进行。1个月后，所有兔子均接受截骨术和牵张成骨，延迟7天，以0.9 mm/d的速度进行11天的主动牵张，然后巩固4周；随后对兔下颌骨进行组织学、放射学和显微计算机断层扫描分析。
随着辐射剂量的增加，骨再生明显受阻。放射学上，高剂量组（8.5和9.0 Gy）的皮质骨线模糊不清。组织学上，在8.5和9.0 Gy组中，皮质骨未完全形成，骨髓腔内存在大量纤维组织。
放疗会影响牵张成骨过程中的骨再生，且不良反应具有剂量依赖性。
