牵张成骨修复腭裂动物实验组织学研究

目的　观察牵张技术修复犬硬腭骨缺损的过程中不同时期新骨形成的结构特点 ,研究新骨形成的连续过程及规律。方法　实验组动物 5只建立人工腭裂模型后使用牵张成骨技术 ,以每次 0 .3mm ,每日 2次的速率牵张关闭裂隙 ,裂隙关闭后每隔 14d以 2 5mg/kg体重为动物肌肉注射四环素 ,分别在裂隙关闭后 2周处死动物 1只 ,6周、10周各处死动物 2只 ,取牵张区新骨组织 ,进行组织学及四环素荧光标记观察。结果　牵张保持期第 2周 ,牵张区为沿牵张方向排列的胶原纤维束 ,其间可见大量成纤维细胞 ,在骨切开边缘区域可见散在荧光带。 6周时 ,牵张区成骨活跃 ,出现沿牵张方向排列的新生骨小梁 ,其间仍可见钙化度低的类骨基质 ,并出现沿骨小梁排列的强荧光带。 10周 ,逐渐成熟的新骨呈现较粗壮的骨小梁 ,钙盐沉积 ,钙化程度高 ,可见较成熟的哈佛氏系统 ,此时因骨改建活跃 ,荧光沉积呈现不连续的线段状。结论　新骨形成是沿牵张方向的膜内成骨方式完成的 ,不同时期新骨的钙化程度及骨改建活跃程度不同 ,新骨组织最终改建成熟而完成硬腭骨缺损修复。

DISTRACTION OSTEOGENESIS FOR CORRECTION OF CLEFT PALATE:THE SUCCESSIVE HISTOLOGICAL STUDY

Objective To observe the structure character of new bone's formation during different period of distraction. To study the continuous process and regularity of new bone formation. Methods Select five dogs as the trial group, and establish cleft palate models. After that, the distraction was carried out with the frequency of 2 times a day and with the rate of 0-3 mm once. On the second week after the closure of cleft, one dog was killed, two dogs on the sixth and tenth week respectively. Every 2 weeks in the stationary phase, tetracycline was intramuscularly injected 25mg/kg. At last the histological study and tetracycline fluorescent marker observation of new bone tissue in the distraction zone. Results Histology and tetracycline fluorescent marker showed that on the second week the distraction zone was filled with fibers arrayed from the distraction direction, within which a lot of fibroblast and osteoblast was found. The dispersal fluorescent zone was observed at the edge of bone. On the sixth week, osteogenesis occurred actively, and the new bone trabecula extended from the distraction direction, within which osteoid tissue and wide fluorescent zone were found. On the tenth week, much maturer bone trabecula had generated and calcium salts had deposited largely. Mature Harvard's system had formed. During that period, the formation of new bone occurred actively and fluorescent zone became narrow and discontinuous. Conclusion The new bone's formation belongs to intramembrane osteogenesis. During different period, the degree of calcification has been different. The final reformation of new bone tissue finished the repairing of hard palate defect.