Immunohistochemical and ultrastructural evaluation of matrix components in mandibular condylar cartilage in comparison with growth plate cartilage in cartilage calcification insufficient rats

• Published in: Anatomical science international Vol. 95; no. 1; pp. 54 - 66
• Main Authors: Shibata, Shunichi, Amano, Hitoshi, Nagayama, Motohiko, Takahashi, Masato, Watanabe, Minoru, Tanaka, Masami
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 2020; Springer Nature B.V
• Subjects: Aggrecan; Anatomy; Animal Anatomy; Animal Physiology; Calcification; Cartilage; Cell Biology; Collagen; Collagen (type I); Decorin; Elongation; Fibrils; Growth plate; Histology; Human Physiology; Hyaluronic acid; Immunoreactivity; Mandible; Medicine; Medicine & Public Health; Morphology; Neurosciences; Original Article; Transmission electron microscopy; Proteoglycan; Growth plate; Condylar cartilage; Collagen; Cartilage calcification insufficient rat
• ISSN: 1447-6959; 1447-073X
• DOI: 10.1007/s12565-019-00493-3

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.