Yoshida M, Zea-Aragon Z, Ohtsuki K, Ohnishi M, Ohno S
Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Yamanashi, Tamaho, Yamanashi, Japan.
Histol Histopathol. 2004 Oct;19(4):1033-41. doi: 10.14670/HH-19.1033.
The purpose of the present study is to clarify native ultrastructures of upper surface layers of the rat mandibular condylar cartilage in vivo by a quick-freezing method. The mandibular cartilaginous tissues were removed with their articular discs attached without opening the lower joint cavity. The specimens were processed for light microscopy, transmission or scanning electron microscopy. Deep-etching replica membranes were also prepared after the routine quick-freezing method. The upper surface layer was well preserved by the quick-freezing method. The cartilaginous tissues, which were fixed without opening their articular discs, appeared to keep better morphology than those after opening them. The upper surface layer was thicker than the corresponding layer as reported before. It consisted of atypical extracellular matrices with lots of apparently amorphous components, which were distributed over typical collagen fibrils, by conventional electron microscopy. As revealed with the replica membranes, it also consisted of variously sized filaments and tiny granular components localized on the typical collagen fibrils. A pair of stereo-replica electron micrographs three-dimensionally showed compact filaments within the upper surface layer. The quick-freezing method was useful for keeping native ultrastructures of the fragile upper surface layer in the mandibular condylar cartilage, which may be functionally important to facilitate smooth movement of the temporomandibular joint.
本研究的目的是通过快速冷冻法阐明大鼠下颌髁突软骨上表层在体内的天然超微结构。在不打开下颌关节腔的情况下，将附着有关节盘的下颌软骨组织取出。对标本进行光镜、透射或扫描电子显微镜检查。在常规快速冷冻法后还制备了深蚀刻复型膜。快速冷冻法很好地保存了上表层。未打开关节盘固定的软骨组织似乎比打开后固定的软骨组织形态保持得更好。上表层比之前报道的相应层更厚。通过传统电子显微镜观察，它由非典型的细胞外基质组成，其中有许多明显无定形的成分，分布在典型的胶原纤维上。正如复型膜所显示的，它还由大小各异的细丝和位于典型胶原纤维上的微小颗粒成分组成。一对立体复型电子显微照片三维显示了上表层内紧密排列的细丝。快速冷冻法有助于保持下颌髁突软骨脆弱上表层的天然超微结构，这对于促进颞下颌关节的平滑运动可能具有重要的功能意义。
