Chen Christopher Phillip, Zhang Jiehua, Zhang Bin, Hassan Mohamed G, Hane Kyle, Chen Caroline C, Navarro Palacios Ana Alejandra, Kapila Sunil, Jheon Andrew H, Goodwin Alice F
Division of Craniofacial Anomalies, Department of Orofacial Sciences University of California, San Francisco (UCSF) San Francisco CA USA.
Program in Craniofacial Biology UCSF San Francisco CA USA.
JBMR Plus. 2022 Jul 3;6(7):e10638. doi: 10.1002/jbm4.10638. eCollection 2022 Jul.
The adaptive response of the mandible and temporomandibular joint (TMJ) to altered occlusion in juvenile patients is presently unclear. To address this question, we established a mouse model in which all molars were extracted from the maxillary right quadrant in prepubertal, 3-week-old mice and analyzed morphological, tissue, cellular, and molecular changes in the mandible and condyle 3 weeks later. Unilateral loss of maxillary molars led to significant, robust, bilateral changes, primarily in condylar morphology, including anteroposterior narrowing of the condylar head and neck and increased convexity at the condylar surface, as determined by geometric morphometric analysis. Furthermore, both condyles in experimental mice exhibited a degenerative phenotype, which included decreased bone volume and increased mineral density near the condylar head surface compared to control mice. Changes in condylar morphology and mineralized tissue composition were associated with alterations in the cellular architecture of the mandibular condylar cartilage, including increased expression of markers for mature () and hypertrophic () chondrocytes, suggesting a shift toward differentiating chondrocytes. Our results show significant bilateral condylar morphological changes, alterations in tissue composition, cellular organization, and molecular expression, as well as degenerative disease, in response to the unilateral loss of teeth. Our study provides a relatively simple, tractable mouse tooth extraction system that will be of utility in uncovering the cellular and molecular mechanisms of condylar and mandibular adaptation in response to altered occlusion. © 2022 The Authors. published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
目前尚不清楚青少年患者下颌骨和颞下颌关节（TMJ）对咬合改变的适应性反应。为了解决这个问题，我们建立了一个小鼠模型，在3周龄青春期前小鼠的上颌右象限拔除所有磨牙，并在3周后分析下颌骨和髁突的形态、组织、细胞和分子变化。通过几何形态计量学分析确定，上颌磨牙单侧缺失导致显著、强烈的双侧变化，主要是髁突形态变化，包括髁突头部和颈部的前后径变窄以及髁突表面凸度增加。此外，与对照小鼠相比，实验小鼠的双侧髁突均表现出退行性表型，包括髁突头部表面附近骨体积减少和矿物质密度增加。髁突形态和矿化组织组成的变化与下颌髁突软骨细胞结构的改变有关，包括成熟（）和肥大（）软骨细胞标志物表达增加，提示向分化软骨细胞转变。我们的结果显示，对单侧牙齿缺失的反应，双侧髁突出现显著形态变化、组织组成改变、细胞组织和分子表达改变以及退行性疾病。我们的研究提供了一个相对简单、易于处理的小鼠拔牙系统，这将有助于揭示髁突和下颌骨对咬合改变的适应的细胞和分子机制。© 作者2022年。由Wiley Periodicals LLC代表美国骨与矿物质研究学会出版。
