咀嚼肌萎缩导致的咬合负荷减少引起的髁突降解。
Condylar Degradation from Decreased Occlusal Loading following Masticatory Muscle Atrophy.
机构信息
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Faculty of Dentistry, Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong.
出版信息
Biomed Res Int. 2018 May 27;2018:6947612. doi: 10.1155/2018/6947612. eCollection 2018.
OBJECTIVE
The masticatory muscles are the most important contributor to bite force, and the temporomandibular joint (TMJ) receives direct occlusal loading. The present study aimed to investigate condylar remodeling after masseter muscle atrophy in rats.
METHODS
Sixty 5-week-old female Sprague-Dawley rats were divided into the following 3 groups: the control group, soft diet (SD) group, and botulinum toxin (BTX) group. The cross-sectional area (CSA) of the masseter muscles was investigated as well as atrogin-1/MuRF-1 expression. Changes in the condylar head were evaluated by H-E, toluidine blue staining, and contour measurements. The biomechanical sensitive factors PTHrP Ihh, Col2a1, and ColX of condylar cartilage were detected by immunohistochemical staining and western blotting. Furthermore, micro-CT and tartrate-resistant acid phosphatase (TRAP) staining were performed to determine the osteopenia in subchondral bone.
RESULTS
The histological and protein analysis demonstrated muscle hypofunction in the SD and BTX groups. Condylar cartilage contour was diminished due to different treatments; the immunohistochemistry and protein examination showed that the expressions of PTHrP, Ihh, Col2a1, and ColX were suppressed in condylar cartilage. A steady osteoporosis in subchondral bone was found only in the BTX group.
CONCLUSION
The current results suggested that a steady relationship between muscular dysfunction and condylar remodeling exists.
目的
咀嚼肌是产生咬合力的最重要因素，而颞下颌关节（TMJ）则直接承受咬合负荷。本研究旨在探讨大鼠咬肌萎缩后髁突的重塑情况。
方法
将 60 只 5 周龄雌性 Sprague-Dawley 大鼠分为以下 3 组：对照组、软食（SD）组和肉毒毒素（BTX）组。研究了咬肌横截面积（CSA）以及萎缩相关基因 Atrogin-1/MuRF-1 的表达情况。通过 H-E、甲苯胺蓝染色和轮廓测量评估髁突头的变化。通过免疫组织化学染色和 Western blot 检测髁状突软骨的生物力学敏感因子 PTHrP、Ihh、Col2a1 和 ColX。此外，还进行了微 CT 和抗酒石酸酸性磷酸酶（TRAP）染色，以确定软骨下骨的骨质疏松情况。
结果
SD 和 BTX 组的组织学和蛋白分析显示肌肉功能低下。不同处理导致髁突软骨轮廓减小；免疫组织化学和蛋白检测显示，PTHrP、Ihh、Col2a1 和 ColX 在髁状突软骨中的表达受到抑制。仅在 BTX 组中发现软骨下骨持续骨质疏松。
结论
目前的结果表明，肌肉功能障碍与髁突重塑之间存在稳定的关系。
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