下颌骨牵张成骨过程中新骨生成的定量组织学观察

Quantitative histomorphometric observation of distraction osteogenesis during mandibular lengthening

目的:对下颌牵张成骨过程中的新骨生成进行动态定量组织学观察,探讨下颌牵张成骨过程中新骨生成的规律。方法:采用牵张成骨术延长10只山羊双侧下颌骨10mm,于术后第10、15、25、35和45天各处死2只动物;另选取2只山羊,不实施手术作为正常对照组。用骨组织形态法评价新生骨组织的形态结构变化;用四环素荧光标记法间接测定新骨的生成速率,并用方差分析法对数据进行统计学分析。结果:从10天组到45天组的平均骨小梁体积分数、平均骨小梁厚度、平均骨小梁数目和新生骨小梁体积密度比均表现为向正常对照组阶梯式递增(P<0.05),而平均骨小梁分隔距离和新生骨小梁表面积密度则表现为向正常对照组阶梯式递减(P<0.05)。从15天组到45天组,成骨细胞活性均显著高于正常对照组(P<0.05);而破骨细胞活性则表现为向正常对照组阶梯式递增(P<0.05)。从15天组到45天组,新骨生成速率与正常对照组相比有3个数量级的差异(P<0.05)。结论:在下颌骨牵张过程中,新生骨小梁由少到多,从幼稚到成熟;新骨生成过程持续活跃;骨吸收改建过程逐渐增强;牵张期新骨生成速率快于固定期。

PURPOSE： To evaluate the regenerating bone during mandibular distraction osteogenesis by bone histomorphometry combining tetracw＇line bone labeling fluorescene microscopy. METHODS： Osteotomy was performed on bilateral mandibles in ten goats. A custom-made distraetor was applied to lengthen the mandible at a rate of lmm/d （0.5mm/12hrs） for ten days. Every two animals were sacrificed at 10d, 15d, 25d, 35d and 45d postoperatively. Two additional goats were used as normal control. The bony specimens were collected and prepared for bone histomorphometry and tetracycline bone labeling fluorescence microscopy with analysis of variance. RESULTS： From 10 days subgroup to 45 days subgroup, bone volume fraction,trabecular thickness,trabeeular number and volume density were gradually increased （P〈0.05）, while trabecular separation distance and surface density were gradually decreased （P〈0.05）. Between 15 days subgroup and 45 days subgroup,the index of osteoblast was significantly higher than normal control （P〈0.05） and index of osteoclast was increased gradually （P〈0.05）. Compared with normal control, bone formation rate was accelerated by thousand times between 15 days subgroup and 45 days subgroup （P〈0.05）. CONCLUSIONS： During the process of mandibular distraction osteogenesis, the bone formation is active, the newly formed bone trabecula gradually become mature, and the remodeling activities of regenerated bone are enhanced gradually. The rate of bone formation within distraction period is faster than consolidation period. Supported by Trans-Century Excellent Teacher Fund of Ministry of Education of China （2002-48）.