Shibata Shunichi, Amano Hitoshi, Nagayama Motohiko, Takahashi Masato, Watanabe Minoru, Tanaka Masami
Department of Maxillofacial Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 113-8549, Japan.
Department of Pharmacology, Osaka Dental University, Hirakata, 573-1121, Japan.
Anat Sci Int. 2020 Jan;95(1):54-66. doi: 10.1007/s12565-019-00493-3. Epub 2019 Jun 14.
Matrix components of growth plate cartilage and mandibular condylar cartilage were immunohistochemically analyzed in cartilage calcification insufficient (CCI) rats, a model for dwarf rats. Reduction in total tibial length, elongation of growth plate, and appearance of noncartilaginous regions in the growth plate were observed in CCI rats. Immunoreactivity for type I collagen and hyaluronic acid (HA) staining were observed in the noncartilaginous region. However, weak immunoreactivity was observed for aggrecan, collagen types II and X, and decorin in this region. Transmission electron microscopy indicated that the noncartilaginous region showed a loose network of thin collagen fibrils, indicating that HA is predominantly involved in capturing space of the noncartilaginous region in the growth plate. Meanwhile, the mandibular condylar cartilage in CCI rats also showed elongation of the cartilaginous region and had a noncartilaginous region, predominantly comprising thick collagen fibrils. The structural difference between the two types of cartilages in CCI rats may be due to the presence of the fibrous cell zone and the fibrocartilaginous nature of the normal condylar cartilage. Additionally, the reduction in mandibular length was relatively less than the reduction in tibial length. The outline of the condylar process showed only slight abnormality. These results suggest that the condylar cartilage compensated its growth by supplying the characteristic noncartilaginous region effectively and may adapt to severe structural changes observed in CCI rats.
在软骨钙化不足（CCI）大鼠（一种侏儒大鼠模型）中，对生长板软骨和下颌髁突软骨的基质成分进行了免疫组织化学分析。在CCI大鼠中观察到胫骨总长度缩短、生长板延长以及生长板中出现非软骨区域。在非软骨区域观察到I型胶原的免疫反应性和透明质酸（HA）染色。然而，在该区域观察到聚集蛋白聚糖、II型和X型胶原以及核心蛋白聚糖的免疫反应性较弱。透射电子显微镜显示，非软骨区域呈现出由细胶原纤维组成的松散网络，表明HA主要参与占据生长板中非软骨区域的空间。同时，CCI大鼠的下颌髁突软骨也显示出软骨区域延长，并有一个主要由粗胶原纤维组成的非软骨区域。CCI大鼠中两种类型软骨的结构差异可能归因于纤维细胞区的存在以及正常髁突软骨的纤维软骨性质。此外，下颌长度的减少相对小于胫骨长度的减少。髁突的轮廓仅显示出轻微异常。这些结果表明，髁突软骨通过有效提供特征性的非软骨区域来补偿其生长，并可能适应在CCI大鼠中观察到的严重结构变化。
