BMP和PDGF在兔下颌牵张后新骨组织中的时空表达

目的 研究骨形成蛋白(BMP)和血小板衍生生长因子(PDGF)在下颌牵张成骨中的表达模式及生物学意义。方法 对15只兔行双下颌骨切开术，安置口外牵张器，经7d间歇期后，按1mm／d的速率延长下颌骨6mm。在间歇期末，牵张结束后0、7、14、28天分别处死3只动物，取牵张区骨痴用免疫组化方法检潮不同时间内BMP和PDGF表达水平的变化。结果 下颌骨牵张后BMP和PDGF表达增强，其阳性信号主要定位于问充质细胞和新生骨小梁边缘的成骨细胞。BMP和PDGF表达高峰均出现在牵张第0和第7天，但BMP在牵张后第28天仅有微弱表达；而PDGF在这个时期的骨痴改建区的成骨细胞中仍有明显表达。结论 BMP可能在牵张成骨过程的早期发挥重要作用，使未分化同充质细胞向骨细胞系分化。PDGF既参与早期的成骨过程，又可能在牵张成骨后期新骨改建中起一定的调控作用。

Temporospatial expressions of BMP and PDGF in the regenerative bone of rabbits during mandibular distraction osteogenesis

Objective To observe the expression patterns of BMP and PDGF in the regenerative bone created by mandibular distraction osteogenesis.Methods Bilateral mandibular osteotomies were performed in 15 rabbits. After a latency of 7 days,the mandibles were lengthened 6mm with a rate of 1mm/d after using a custom distractor.Three rabbits were killed at the end of intermission and at 0,7 th ,14 th ,28 th days after distraction, respectively.The distracted calluses from all rabbits were harvested and processed for immunohistochemistry of BMP and PDGF.Results Elevated expressions of BMP and PDGF were observed following mandibular distraction osteogenesis.Positive staining for BMP and PDGF was mainly seen in the mesenchymal cells and the active osteoblasts at the edge of newborn trabecular bone.Their strongest expression was noted at 0 and the 7 th days after distraction.At the 28 th days after distraction,moderate staining for PDGF was observed in the osteoblasts at remodeling sites,but only weak BMP expression was detected in those cells.Conclusion Both BMP and PDGF may play important roles in inducing mesenchymal cells to differentiate into osteoblasts at the early stage of distraction, besides this PDGF may also take part in the process of new bone remodeling at the late stage of distraction.