Saitoh S, Takahashi I, Mizoguchi I, Sasano Y, Kagayama M, Mitani H
Clinics for Maxillo-Oral Disorders, Tohoku University Dental Hospital, Aoba-ku, Sendai, Japan.
Anat Rec. 2000 Dec 1;260(4):392-401. doi: 10.1002/1097-0185(20001201)260:4<392::AID-AR90>3.0.CO;2-O.
Midpalatal suture cartilage (MSC) is secondary cartilage located between the bilateral maxillary bones and has been utilized in the analysis of the biomechanical characteristics of secondary cartilage. The present study was designed to investigate the effects of compressive force on the differentiation of cartilage in midpalatal suture cartilage in rats. Forces of various magnitudes were applied to the midpalatal suture cartilage in 4-week-old male Wistar rats for 1, 2, 4, 7, or 14 days, mediated through the bilateral 1st molars using orthodontic wires. The differentiation pathways in the MSC cells were examined by immunohistochemistry for the differentiation markers type I, type II and type X collagen, and glycosaminoglycans (GAGs), chondroitin-4-sulfate, chondroitin-6-sulfate and keratan sulfate. Histologically and immunohistochemically, the midpalatal suture cartilage in control rats had the characteristic appearance of secondary cartilage. In the experimental groups, the center of the midpalatal suture cartilage that contained osteo-chondro progenitor cells seemed to become mature cartilage and its immuno-reaction to type II and X collagen and GAGs increased as the experiment progressed. This differentiation was dependent upon the magnitude and duration of the force applied to the midpalatal suture cartilage; i.e., cartilaginous differentiation progressed more rapidly as the applied force increased. The present results suggest that the differentiation of osteo-chondro progenitor cells into mature and hypertrophic chondrocytes in the precartilaginous cell layer is promoted by compressive force.
腭中缝软骨（MSC）是位于双侧上颌骨之间的继发性软骨，已被用于分析继发性软骨的生物力学特性。本研究旨在探讨压力对大鼠腭中缝软骨中软骨分化的影响。通过正畸钢丝经双侧第一磨牙对4周龄雄性Wistar大鼠的腭中缝软骨施加不同大小的力，持续1、2、4、7或14天。通过免疫组织化学检测MSC细胞中I型、II型和X型胶原蛋白以及糖胺聚糖（GAGs）、硫酸软骨素-4、硫酸软骨素-6和硫酸角质素等分化标志物的分化途径。在组织学和免疫组织化学上，对照大鼠的腭中缝软骨具有继发性软骨的典型外观。在实验组中，含有骨软骨祖细胞的腭中缝软骨中心似乎变成成熟软骨，并且随着实验的进行，其对II型和X型胶原蛋白以及GAGs的免疫反应增加。这种分化取决于施加到腭中缝软骨上的力的大小和持续时间；即，随着施加力的增加，软骨分化进展得更快。目前的结果表明，压力促进了软骨前细胞层中骨软骨祖细胞向成熟和肥大软骨细胞的分化。
