兔下颌骨放疗后牵张成骨动物模型的建立

目的探讨建立兔下颌骨放疗后牵张成骨动物模型的可行性。方法24只成年新西兰大白兔随机分为放疗组和未放疗组,每组12只。放疗组采用60Co放疗机照射兔下颌骨,5.4Gy/次,隔日1次,共5次。3个月后在2组兔下颌骨的双侧截骨处安装牵张器,经5d延迟期后开始牵张,速率为1mm/d,0.5mm/次,每日2次,连续7d,共延长下颌骨7mm。固定期的第0、4、6周摄下颌骨侧位X线片。固定期的第4、6周分别取出下颌骨行组织学观察。结果兔对放疗和牵张成骨术耐受良好,未见放疗引起的不良反应。X线片有新骨形成,未见死骨;组织学观察见放疗组较未放疗组有更多软骨形成。结论兔是一种用于建立放射损伤区牵张成骨模型的良好动物。

Establishment of Experimental Distraction Osteogenesis Model in Rabbits' Mandibles after Radiation Injury

Objective To investigate the feasibility of distraction osteogenesis in irradiated rabbits mandible. Methods 12 New Zealand white rabbits were irradiated by 60Co, 5.4 Gy every time, one time every other day, five times totally. Anterior mandibulectomy was performed bilaterally and distractors were fixed three months later. The distractors were activated 0.5 mm every 12 hours to extend the anterior segment 7 mm for 7 days after latency phase of 5 days. X-ray photographs were taken at consolidation phase of 0, 4, 6 weeks. The distracted calluses at consolidation phase of 4, 6 weeks were processed for histopathology analysis. Results The rabbits could tolerate distraction osteogenesis after radiotherapy and had no adverse reaction. There was new bone and no dead bone according to radiograph. More cartilages and less new matured bones in irradiated group were formed than that of non-irradiated group at consolidation phase. Conclusion The rabbit model is suitable for study of distraction osteogenesis in irradiated tissues.