The effect on the temporomandibular joint morphogenesis and its development by restriction of jaw movement in mice

通过上下颌骨固定，胚胎未发现明显的全身性生长迟缓。但在口内活动受限的颞下颌部，下颌骨软骨与颈部钙化骨间边界不清，肉眼可见弥漫性钙化。在髁状突头的软骨膜内可见细胞变形、排列紊乱，增生区与前肥大区之间也可见异常骨化，细胞排列不连续为特征。这一发现表明，颌骨运动在颞颌关节的产前发育中起着重要作用。碱性成纤维细胞生长因子(b-FGF)及其受体(FGFR-3)的免疫组织化学染色和免疫印迹显示，胚胎15.5天和17.5天的软骨细胞表面不表达碱性成纤维细胞生长因子及其受体，而是较深的增殖层和肥大前期。B-FGF和FGFR-3在不同性别的成人软骨细胞浅层呈强阳性表达，并逐渐向深层表达。这些分子似乎在钙化机制中起作用。免疫印迹分析显示，FGFR-3在正常生长阶段的胎龄为15.5天、胎龄为17.5天和出生后11日龄时有较高的染色强度，而在成年胎儿中的染色强度较弱。对照组B-FGFs呈类似趋势，但成人组最多仅见少量染色。

By the maxillo-mandibular fixation, no significant systemic growth retardation of the embryo was not detected. But at the temporomandibular portion of the mouth movement restriction, the border between the cartilage of the condylar head and the calcified bone in the neck became unclear and diffuse macroscopically.Deformed and disarranged cells were found in fee perichondrium of the condylar head, furthermore abnormal ossification was also observed between the proliferating and prehypertrophic zones and therefore discontinuity cell arrangement was characteristic. This finding suggested that jaw movement played an important role in the prenatal development of the temporomandibular joint. From the immunohistochemical staining and western blotting method of basic fibroblast growth factor (b-FGF) and its receptor (FGFR-3) revealed high stainability not in the superficial condylar chondrocytes but rather deeper proliferating and prehypertrophic zones at the embryonic day (E) 15.5, and E17.5. While in adults of both sex, b-FGF and FGFR-3 showed a high stainability in the superficial chondrocyte zone and gradually decreased towards to deeper zones. These molecules seemed to function in the mechanisms of calcification. Western blotting analysis of FGFR-3 in the normal growth showed a high stainability at the E 15.5, E 17.5 and at 11th day birth but in adult it revealed a weak stainability. B-FGF in the control group revealed a similar tendency but in adult at most little staining was observed.