生長期迷你豬施行單側下顎骨 牽引性骨生成術之顳顎關節變化

Changes of TMJ Following Mandibular Distraction Osteogenesis in Growing Mini-pigs

黃繼瑩(Chi-Ying Huang)

指導教授 ： 姚宗珍

國立臺灣大學/醫學院/臨床牙醫學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.02536

摘要

牽引性骨生成術(Distraction Osteogenesis)廣泛應用於治療成長期中顱顏部發育異常的病患，使之能夠提早建立正常的生理性功能。然而文獻中關於下顎牽引性骨生成術造成顳顎關節的變化尚無定論，其中又很少將生長因素列入考量。本實驗的目的即為以生長期迷你豬為實驗對象，探討單側下顎牽引性骨生成術對顳顎關節的影響。
實驗共計14隻具有生長潛力的迷你豬(年齡分布為5週至12週大，體重從6公斤到15公斤)，分成四組：(1)實驗組A，n=5，實驗側施行單側下顎骨截斷並裝置口內延長器，術後經過7天的延遲期，每天以0.9公釐的速度逐漸延長下顎，共延長14天，延長完成當日進行犧牲。(2)實驗組B，n=2，延長完成後固定4週再進行犧牲，以觀察長期的變化。(3)控制組，n=5，實驗側施行單側下顎骨截斷並裝置口內延長器，但未實施牽引。(4)正常組，n=2，為與實驗組B犧牲時年齡相近的健康迷你豬，作為提供正常組織的對照。研究共分四部分探討顳顎關節的變化：(1)以立體重組影像觀察下顎髁頭形態變化及下顎髁頭與顳窩相對位置改變情形。(2)以HE染色法觀察組織學特徵及比較關節軟骨厚度變化。(3)以免疫組織化學染色法觀察軟骨層中MMP9蛋白分佈的情形。(4)以TUNEL偵測法觀察軟骨層中細胞凋亡的情形。
結果顯示，顳顎關節在牽引作用下會有形態、位置及組織學上的改變，而其作用牽引側比控制側明顯；牽引結束後立即觀察，軟骨下成骨活動及基質代謝速率上升，但是經過4週的固定期，軟骨厚度略為變薄，這些變化也會有逐漸回復的現象，顯示生長期中迷你豬的關節軟骨適應能力；根據下顎髁頭相對位置改變情形以及關節軟骨厚度變化情形，推測牽引過程中，髁頭的外側1/3及中側1/3部分為受力較大部分；另外，牽引在顳顎關節區域產生的力量並未顯著地使細胞凋亡的數目增加。因此，牽引性骨生成術以能夠有效地延長下顎，而其對顳顎關節的影響似乎為暫時性的，惟在形態上的變化以及可能對下顎運動功能的影響仍須更長期的追蹤觀察。

關鍵字

牽引性骨生成術 ； 迷你豬 ； 顳顎關節 ； 軟骨細胞

並列摘要

Distraction osteogenesis has been widely used in congenital anomalies to correct craniofacial deficiency. Clinically it is frequently conducted on growing patients for early establishment of normal physiological functions. However, the effects on temporomandibular joints due to mandibular distraction are still controversial, and the influence of growth was not taken into consideration in most of the research. In this study, we investigated the effects on TMJs in growing mini-pigs in which unilateral mandibular distraction osteogenesis was performed.
Fourteen (5~12 weeks, 6~15kg weight) Lee-Sung genus of mini-pigs were divided into 4 groups: 1) Experimental group A (n=5), received osteotomy and the distractor device (Leibinger intraoral distractor) was fixed on one side of the mandible. After one-week latency period, the mandible was distracted for 2 weeks with the velocity of 0.9 mm/day. At the end of distraction, the animals were sacrificed immediately. 2) Experimental group B (n=2), the animals received the similar treatment as Experimental group A, except that they were sacrificed after a consolidation period of 4 weeks for the long-term observation. 3) Control group (n=5), received osteotomy but the distractor device was placed without distraction. And 4) Normal group, 2 healthy mini-pigs without any operation were used to provide information of normal structures.
Changes of temporomandibular joints in the experimental groups were detected from 4 different approaches. 1) Using three-dimensional reconstruction using MRI image data, to observe morphological changes of mandibular condyle and relative position between temporal fossa and condyle. 2) From the H & E staining of different portion of the condyles, to observe histological characteristics and changes of thickness of condylar cartilage. 3) Via immunohistochemical analysis, to observe the distribution of MMP9 in cartilage. 4) Using TUNEL staining method, to detect apoptosis in chondrocytes in the sections of condylar cartilage.
There were detectable changes in morphology, position and histological characteristics of condyle after unilateral mandibular distraction and the extent of changes was more obvious at the distraction side than control side. Increased activities of subchondrol ossification and matrix degradation after distraction were noticed. After a 4-week consolidation, these changes returned to the normal level; however, the thickness of cartilage decreased. These findings revealed the enormous adaptive capacity of condyle in growing animals. Changes in the position of condyle and thickness of cartilage also suggested that the lateral and middle third of condylar head were under higher degree of loading. Additionally, the number of apoptotic chondrocytes did not obviously increase under distraction.
In conclusion, distraction osteogenesis is an effective way to lengthen the mandible with minimal and transient changes of TMJ. A more long-term observation is required to follow the morphological change of condyle and its consequences on the mandibular movement and function if it is not a reversible process.

並列關鍵字

distraction osteogenesis ； mini-pig ； temporomandibular joint ； chondrocyte

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