大鼠下颌骨牵张成骨模型的改进

目的：建立一个新的可行性和重复性俱佳的大鼠下颌骨牵张成骨模型?方法：对30只雄性大鼠从升支前缘中部至下颌下缘行全层骨切开，并安放特制的纯钛牵张器．用螺钉固定5d延迟期后．以0．2mm／次、2次／d的速度进行牵张，共8d；随后进入固定期：分别于固定期第2、4、8周分3批处死大鼠，进行大体标本观察和放射学、组织学检测。结果：实验过程被所有大鼠很好的耐受，切口感染率低(6．7％)．无牵张器脱落。大体标本观察表明，在牵张间隙形成了很好的骨痂组织．牵张间隙达到了预期的长度：新生骨组织放射学和组织学表现与大动物的表现相似。结论：我们成功建立了一个新的可行性和重复性俱佳的大鼠下颌骨牵张成骨模型；该模型有助于牵张成骨分子机制的进一步深入研究。

A New Rat Model for Mandibular Distraction Osteogenesis

Objective: To establish a new rat model for mandibular distraction with good feasibility and reproducibility. Methods: Thirty male SD rats were used in this study. Osteotomy was performed from the middle of anterior ramus border to the inferior border of the mandible and two drill holes were created with 2mm anterior or posterior to the osteotomy line. A custom-made distractor was then placed at the osteotomy site and secured with two screws. After a 5-day latency, the rats were distracted at a rate of 0.2mm twice per day for 8 days followed by a consolidation period. The distracted mandibles were harvested after 2, 4, and 8 weeks of consolidation and the appearance of the samples, radiological and histological changes were examined. Results: The experimental procedure has been well tolerated by all animals with a very low infection rate (6.7%). There were no device dislodgments. Postmortem examination showed good callus formed in the distraction gap and expected distraction length was successfully achieved. The radiological and histological changes of the new bone were similar to those happened in large animals. Conclusion: We have successfully developed a new rat model for mandibular lengthening with a custom-made distractor. This model has shown perfect feasibility and reproducibility, and therefore should be effective for further investigations on molecular mechanism of distraction osteogenesis.