咬合垂直距离降低对大鼠髁突软骨和软骨下骨形态学影响的初步研究

目的:探讨咬合垂直距离降低对大鼠颞下颌关节髁突软骨和软骨下骨改变的影响。方法:40只10周龄雄性大鼠随机等分为实验组和操作对照组。实验组通过降低大鼠牙冠高度的方法建立咬合垂直距离降低的动物模型,分别于处理后3、10、20、30d处死取材。30d组大鼠于实验处理前1d、处理后10、30d进行MICRO-CT扫描观察大鼠髁突软骨下骨形态改变。双侧颞下颌关节石蜡包埋、切片,通过HE染色观察大鼠髁突软骨形态学的改变。结果:①实验3d组与10d组髁突软骨中部厚度较操作对照组明显增厚(P<0.05),但实验20d组和30d组软骨中部厚度与操作对照组之间无显著差异(P>0.05)。所有实验组髁突软骨后部厚度在各时间点均较操作对照组显著增厚(P<0.05);②实验3d组髁突软骨增殖层出现了较大面积的胞核固缩,实验10d组部分关节(4/10)髁突软骨中出现了均质样无细胞区域,实验20d组与30d组髁突软骨各层形态基本与对照组相似;③实验30d组于10d时可见髁突软骨下骨后部出现骨质吸收凹陷,实验30d时凹陷变浅,骨表面又趋于光滑流畅。结论:①咬合垂直距离降低可以引起大鼠髁突软骨中后部的适应性改建;②实验早期改建活动较活跃,晚期改建活动趋于稳定。

A preliminary study on the effect of decreased occlusal vertical dimension on the morphology of rat condylar cartilage and subchondral bone

AIM:To study the effects of the decreased occlusal vertical dimension on the morphology of the rat condylar cartilage and subchondral bone.METHODS:Forty 10-week-old male SD rats were used in this study. The rats were randomly assigned into sham-control and experimental group.The decreased occlusal vertical dimension model was established by reducing the crown height.Five rats from each group were sacrificed at the time-point of 3, 10,20 and 30 days after experiment beginning.The morphology of rat's condylar...