Development of a Technique Promoting Ossification in the Distraction Osteogenesis

牵张成骨技术是一种实用可靠的骨再生技术。然而，牵张技术需要较长的牵张区成骨周期。在本研究中，为了改善牵张技术的这一缺点，我们试图识别在牵张区表达的各种生长因子，并将这些生长因子应用于牵张区以促进骨形成。我们在我们实验室建立的兔下颌骨上建立了牵张模型。此外，我们还尝试在狗的下颌骨中建立这种牵张模型，并将实验动物扩展成猴子。然而，在现阶段，由于下颌骨牵张的重复性，我们在兔身上进行了实验。在兔实验中，某些生长因子的mRNAs在牵张区表达。然而，我们不能完全确定这些增长因素。另一方面，骨形态发生蛋白(BMP)促进兔下颌骨牵张区的骨形成，且在牵张后最后一天给药比第一天给药更有效。现在，我们试图使用除BMP之外的其他生长因子来检验一个类似的实验。此外，我们还观察了牵引成骨和一期骨延长时下颌骨周围软组织(肌肉和粘膜)的组织学差异。当我们对下颌骨周围的软组织进行免疫组织学检查时，牵张成骨中的组织再生比一期骨延长中的组织再生更为活跃。牵张成骨被称为牵张组织成骨。我们认为，阐明软组织中的牵张组织发生也是关于牵张成骨的一个重要主题。

The distraction osteogenesis is a useful and reliable technique for bone regeneration. However, the distraction technique needs long period for bone formation in the distraction zone. In this study, in order to improve this disadvantage of the distraction technique, we tried to identify various growth factors expressed in the distraction zone and apply these growth factors to the distraction zone to promote bone formation. We used a distraction model in the rabbit mandible established in our laboratory. In addition, we tried to establish this kind of distraction model in the dog mandible and expand the experimental animal into monkey. However, in the present stage, we perform experiments of the mandibular distraction in rabbits because of its reproducibility. In the rabbit experiment, mRNAs of some kinds of growth factors were expressed in the distraction zone. However, we could not completely identify these growth factors. On the other hand, bone morphogenetic protein (BMP) promoted bone formation in the distraction zone of the rabbit mandible and its administration was more effective on the last day than on the first day of distraction. Now, we try to examine a similar experiment using other growth factors except BMP. Moreover, we observed the histological difference in the soft tissue (muscle and mucous membrane) surrounding mandible between in distraction osteogenesis and one-stage bone extension. When we examined the soft tissue surrounding mandible immunohistologically, tissue regeneration was more active in the distraction osteogenesis than in the one-stage bone extension. The distraction osteogenesis is said to be distraction histiogenesis. We believe that elucidation of the distraction histiogenesis in the soft tissue is also an important theme regarding distraction osteogenesis.