〔摘要〕　目的：检测髁状突骨上组织细胞及细胞外基质超微结构在负荷改变后的变化特点。方法：4只成年家兔在被拔除双侧下颌磨牙后1月和3月，用透射电镜的方法观察组织的表现。结果：细胞发生了不同程度的改建及退行性反应，如粗面内质网的扩张，线粒体肿胀，溶酶体增多等；基质中胶原原纤维的有序排列结构消失，胶原网受到破坏，同时蛋白多糖颗粒减少；基质中脂质小体及基质小囊等成分增多；负重区较非负重区的改变更显著。结论：过重的负荷会超过组织的代偿能力，使细胞产生基质的能力下降，对细胞自身产生不利的影响，引起髁状突的弹性及抗压、抗磨擦等能力的下降。

The ultrastructure changes of cells and extracellular matrix in the supraosseous tissue of mandibular condyle following load change

Duan Xiaohong, Wang Huiyun.

　　Dept. of Oral Anatomy and Physiology, Stomatological College, Fourth Military Medical University, Xi'an, 710032

　　〔Abstract〕Objective: To observe the ultrastructure changes of the supraosseous tissues of mandibular condyle following load change.Methods:The ultrastructure of supraosseous tissues of 4 adult rabbits were observed under transmission electron microscope 1～3 months after removal of the bilateral lower molars. Result:After removal of the bilateral lower molars, the remodeling and degenerative activities in different layers of the condyles increased, such as vesiculation of endoplasmic reticulum, distortion of mitochondria and increase of lysosome. Furthermore, the sequential arrangement of collagen fibrils was disturbed, the collagen network broke down and the proteoglycan granules decreased. The number of lipid globules and matrix vesicles increased. Load-bearing areas showed more changes than unload-bearing areas. Conclusion:Overloading beyond the adaptive abilities of the tissue may cause a decrease of matrix's synthetic activity of the cells and degenerative changes of the ultrastructure of the cells and matrix.

　　Key words Mandibular condyle; Ultrastructure; Collagen; Proteoglycans; Electron microscopy

　　近年来，采用扫描电镜和透射电镜(transmission electron microscopy,TEM)方法对颞下颌关节疾病的研究取得了一些结果，但关于髁状突骨上组织细胞外基质(extracellular matrix,ECM)的研究甚少，尤其是在负荷改变对基质的影响方面。本研究采用拔除成年家兔双侧下颌磨牙的方法，间接造成关节负荷的加重，用TEM观察髁状突负重区和非负重区的骨上组织细胞及ECM在实验后1月和3月时的表现。

　　1　材料和方法

　　8只成年家兔(本校实验动物中心提供)为实验对象，分为2组，每组中2只为实验动物，另外2只为对照，雌雄随机。实验动物在846合剂麻醉下拔除双侧下颌磨牙，实验动物和对照动物在相同条件下喂养。2组动物全麻下取样，分别从左侧髁状突的前斜面和后斜面切取大小约1mm×1mm×3mm的骨上组织，30g/L戊二醛4℃条件下固定，0.1mol/L磷酸缓冲液冲洗，10g/L锇酸固定，冲洗后丙酮逐级脱水，混合液浸透，Epon812包埋，光镜下定位，制备超薄切片后，醋酸铀和柠檬酸铅双重染色，JEM2000EX透射电镜观察。右侧髁状突做常规HE染色，光镜观察。

　　2　结　果

　　2.1光镜结果　对照组髁状突骨上组织分纤维表层、增殖层和软骨层。前斜面和后斜面相比，后者纤维层较厚，细胞成分多，增殖层连续，软骨细胞排列较为致密。3月组比1月组细胞成分较少，余无明显差异。

责任编辑：韩晓炜