Takahashi I, Mizoguchi I, Nakamura M, Sasano Y, Saitoh S, Kagayama M, Mitani H
Department of Orthodontics, Tohoku University, Sendai, Japan.
Bone. 1996 Apr;18(4):341-8. doi: 10.1016/8756-3282(96)00012-9.
In an attempt to clarify the effects of biomechanical tensional force on chondrogenic and osteogenic differentiation of secondary cartilage, the midpalatal sutures of 4-week-old Wistar male rats were expanded by orthodontic wires which applied 20 g force for 4, 7, 10, and 14 days. The differentiation pathways in the midpalatal suture cartilage were examined by immunohistochemistry for osteocalcin, type I and type II collagen, and von Kossa histochemistry. Although the midpalatal sutures of the control animals consisted mainly of two separate secondary cartilages with mesenchyme-like cells at their midlines, type I collagen-rich fibrous tissue began to appear at day 4 and increased at the midline of the cartilage with days of experiment. At the end of the experiment, type I collagen-rich and calcified bone matrix appeared at the boundary between the precartilaginous and the cartilaginous cell layers. Most of the cartilaginous tissues were separated from each other and the midpalatal suture was replaced by osteocalcin-positive intramembranous bone and fibrous sutural tissue. These results strongly suggest that tensional force changed the phenotypic expression of collagenous components in secondary cartilage, which may reflect the differentiation pathway of osteochondro progenitor cells.
为了阐明生物力学张力对继发软骨成软骨和成骨分化的影响，对4周龄雄性Wistar大鼠的腭中缝用正畸丝进行扩展，施加20 g力，持续4、7、10和14天。通过免疫组织化学检测骨钙素、Ⅰ型和Ⅱ型胶原以及冯·科萨组织化学，研究腭中缝软骨中的分化途径。虽然对照动物的腭中缝主要由两个独立的继发软骨组成，在其中线处有间充质样细胞，但富含Ⅰ型胶原的纤维组织在第4天开始出现，并随着实验天数的增加在软骨中线处增多。在实验结束时，富含Ⅰ型胶原和钙化的骨基质出现在软骨前细胞层和软骨细胞层之间的边界处。大多数软骨组织相互分离，腭中缝被骨钙素阳性的膜内骨和纤维性缝组织所取代。这些结果有力地表明，张力改变了继发软骨中胶原成分的表型表达，这可能反映了骨软骨祖细胞的分化途径。
