失感觉神经支配大鼠下颌骨牵张成骨动物模型的建立

A new rat model of missing the inferior alveolar nerve for mandibular distraction osteogenesis

目的:建立一个新的可行性和重复性俱佳的失感觉神经支配大鼠下颌骨牵张成骨模型。方法:24只大鼠随机分为2组,实验组大鼠先自下颌孔至颏孔切除下齿槽神经后,从升支前缘至下颌骨下缘行全层骨切开,用螺钉固定特制的钛牵张器,对照组为保留下齿槽神经的大鼠下颌骨牵张成骨,5d延迟期后,均进行单侧下颌骨牵张,速率:0.2mm/12h,牵张期为10d,随后进入固定期。分别于固定期第14d、28d处死大鼠,进行大体标本观察和组织学检测。结果:实验过程被所有24只大鼠很好的耐受,切口感染率低,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。感觉神经缺失对牵张成骨具有负面调节作用。结论:成功建立了一个新的可行性和重复性俱佳的失感觉神经支配大鼠下颌骨牵张成骨模型,该模型有助于感觉神经对牵张成骨影响的分子机制的进一步深入研究。

Objective： To establish a new rat model of missing the inferior alveolar nerve for mandibular distraction os- teogenesis with good feasibility and reproducibility. Methods： 24 rats were divided into two groups randomly, the experi- mental group of rats missing mandibular distraction osteogenesis of the inferior alveolar nerve, the control group was nor- mal rat mandibular distraction osteogenesis, were carried out under the unilateral mandibular distraction. Osteotomy was performed from the anterior ramus border to the inferior border of the mandible.A custom made distractor was then placed at the osteotomy site and secured with screws. After a 5 days latency, the rats were distracted at a rate of 0.2mm twice per day for 10 days followed by a consolidation period. The distracted mandibles were harvested after 14 and 28 days of consol- idation and the appearance of the samples and histological changes were examined. Results： The experimental procedure has been well tolerated by 24 animals with a very low infection rate. There were no device dislodgments. Postmortem ex- amination 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. The sensory nerve resection can degrade new bone formation, which suggests that the sensory nerve plays a role during the new bone formation in the distraction osteogenesis. Conclusion： We have successfully developed a new rat model of missing the inferior alveolar nerve for mandibular distractor. This model has shown perfect feasibility and reproducibility, and therefore should be effec- tive for further investigations on molecularmechanism of distraction osteogenesis.