牵张成骨术整复猕猴腭裂模型成骨超微结构与成分研究

目的 研究牵张成骨术整复腭裂缺损在不同时间段新骨的超微结构及其Ca、P元素能谱特征,探讨其原位骨生成与改建规律.方法 猕猴共25只,23只以外科方法建立腭裂动物模型,另2只不做任何处理作为空白对照.实验组21只,应用牵张成骨术整复其腭部软硬组织缺损,以每天2次、每次0.4 mm的速率进行牵张,至骨运送盘移动关闭裂隙后原位固定.分别于固定期第1、2、4、6、8、12及24周取材,每次3只动物.将标本置于扫描电镜下观察,进行元素能谱分析,并与实验对照组(2只,不进行牵张成骨)及空白对照组观察结果比较.结果 术后固定期第1～2周,牵张区以沿牵张方向排列的胶原纤维束为主,少量新生骨小梁形成;第4～6周,成骨活跃,新生骨小梁细胞成分丰富;第8～12周,新骨逐渐钙化成熟,新旧骨交界不明显;至第24周,新生骨质与正常结构相似.元素能谱分析结果提示:整个成骨过程中,P、S元素峰相对于Ca元素峰的比值逐渐逆转,Ca/P比例逐渐增高.至术后8周,各元素分布及含量表明骨质钙化已完善,转入改建成熟阶段至接近正常;至24周时Ca/P元素质量比达2.06±0.10,原子计数比达1.60±0.08,与正常对照组的数值比(2.08±0.04、1.61±0.03)已无明显差异.结论 应用牵张成骨术矫治腭裂骨质缺损,口内牵张装置有效推动骨运送盘通过膜内成骨的方式,新骨不断的成熟和改建,最终封闭裂隙,原位新生骨组织改建成熟至正常结构,恢复腭部连续性.

Ultrastructural and element spectrometric analysis of distraction osteogenesis for reconstruction of cleft palate in rhesus macaque model

Objective To study the ultrastructure and Ca/P clement spectrometry of distraction osteogenesis (DO) for reconstruction of cleft palate ( CP), so as to explore the osteogenesis and remodeling of new bone in situ. Methods 23 rhesus macaques were operated to establish animal models of CP. 2 monkeys didn't received DO as controls. The other 21 monkeys in experimental group underwent DO to correct both bony and soft tissue defects in palate. The distraction was performed at a rate of 0.8 mm/d,twice a day until the cleft was closed. After fixation for 1, 2, 4, 6, 8, 12, 24 weeks, every 3 animals were sacrified to get the specimens at the distraction gap. The scanning electron microscopic study and Ca, P elements spectrometric analysis were adopted. There were also two unoperated animals as sham group.Results After fixation for 1-2 weeks, the distraction gap was full of collagen fibers oriented along vector of distraction. Few trabeculae was seen at the margin area. After fixation for 4-6 weeks, active osteogenesis was presented with new formed bone trabeculae and aboundant cellular component. After fixation for 8-12 weeks, the new formed bone became mature and couldn't distinguish from the normal bone. 24 weeks later,the bone between the distraction gap had a similar structure to the normal bone. Elements spectrometricanalysis results indicated that in early stage of osteogenesis, the P and S peaks were relatively high whilethe Ca peak was much lower. During the late stage, the S peak was obviously decreased, and Ca/P ratio increased to normal level as in the empty control group. Conclusions The CP can be corrected by DO.The new bone between the distraction gap is formed and remodeled through intramembraneous osteogenesis.