颞下颌关节在负荷改变下的结构-功能关系。
Structure-Function Relationships of the Temporomandibular Joint in Response to Altered Loading.
出版信息
J Oral Facial Pain Headache. 2019 Fall;33(4):451–458. doi: 10.11607/ofph.2094. Epub 2019 Jul 24.
AIMS
To elucidate the effects of decreased occlusal loading (DOL), with or without reloading (RL), on the structure and bite force function of the mandibular condylar fibrocartilage in skeletally mature male mice.
METHODS
At 13 weeks old, 30 wild type (WT) male mice were subjected to: (1) 6 weeks normal loading (NL); (2) 6 weeks DOL; or (3) 4 weeks DOL + 2 weeks RL. Histomorphometry, cell metabolic activity, gene expression of chondrogenic markers, and bite force tests were performed.
RESULTS
DOL resulted in a significant increase in apoptosis (P < .0001) and significant decreases in fibrocartilage thickness (P < .05) and hypertrophic chondrocyte markers indian hedgehog and collagen type X (P < .05). A corresponding decrease in bite force was also observed (P < .05). RL treatment resulted in a return to values comparable to NL of chondrogenic maturation markers (P > .10), apoptosis (P > .999), and bite force (P > .90), but not in mandibular condylar fibrocartilage thickness (P > .05).
CONCLUSIONS
DOL in skeletally mature mice induces mandibular condylar fibrocartilage atrophy at the hypertrophic cell layer with a corresponding decrease in bite force.
目的
阐明咬合负荷减少（DOL），无论是否重新加载（RL），对骨骼成熟雄性小鼠下颌髁突纤维软骨的结构和咬合力功能的影响。
方法
在 13 周龄时，将 30 只野生型（WT）雄性小鼠分为以下三组：（1）6 周正常加载（NL）；（2）6 周 DOL；或（3）4 周 DOL+2 周 RL。进行组织形态计量学、细胞代谢活性、软骨形成标志物的基因表达和咬合力测试。
结果
DOL 导致细胞凋亡显著增加（P<0.0001），纤维软骨厚度显著减少（P<0.05），肥大软骨细胞标志物印度刺猬和胶原 X 型减少（P<0.05）。同时也观察到咬合力的相应下降（P<0.05）。RL 处理导致软骨形成成熟标志物（P>0.10）、细胞凋亡（P>0.999）和咬合力（P>0.90）恢复到与 NL 相当的值，但下颌髁突纤维软骨厚度没有恢复（P>0.05）。
结论
在骨骼成熟的小鼠中，DOL 导致下颌髁突纤维软骨在肥大细胞层发生萎缩，同时咬合力相应下降。
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