An immunohistochemical study of matrix proteins in the craniofacial cartilage in midterm human fetuses

Abstract

Immunohistochemical localization of collagen types I, II, and X, aggrecan, versican, dentin matrix protein (DMP)-1, martix extracellular phosphoprotein (MEPE) were performed for Meckel’s cartilage, cranial base cartilage, and mandibular condylar cartilage in human midterm fetuses; staining patterns within the condylar cartilage were compared to those within other cartilaginous structures. Mandibular condylar cartilage contained aggrecan; it also had more type I collagen and a thicker hypertrophic cell layer than the other two types of cartilage; these three characteristics are similar to those of the secondary cartilage of rodents. MEPE immunoreactivity was first evident in the cartilage matrix of all types of cartilage in the human fetuses and in Meckel’s cartilage of mice and rats. MEPE immunoreactivity was enhanced in the deep layer of the hypertrophic cell layer and in the cartilaginous core of the bone trabeculae in the primary spongiosa. These results indicated that MEPE is a component of cartilage matrix and may be involved in cartilage mineralization. DMP-1 immunoreactivity first became evident in human bone lacunae walls and canaliculi; this pattern of expression was comparable to the pattern seen in rodents. In addition, chondroid bone was evident in the mandibular (glenoid) fossa of the temporal bone, and it had aggrecan, collagen types I and X, MEPE, and DMP-1 immunoreactivity; these findings indicated that chondroid bone in this region has phenotypic expression indicative of both hypertrophic chondrocytes and osteocytes.

An Immunohistochemical Study of Matrix Components in Early‐Stage Vascular Canals Within Mandibular Condylar Cartilage in Midterm Human Fetuses

“…Our findings from histological and histochemical studies of mice support this narrow definition (Shibata et al, ; ; ; Shibata and Yokohama‐Tamaki, ). Recently, we analyzed human midterm fetuses, focusing on the matrices of human mandibular condylar cartilage, including the perichondrium, and confirmed that this definition is also valid for human (Shibata et al, ). In addition, we demonstrated that tenascin‐ C is a marker of periosteum in human fetuses, and the perichondrium of condylar cartilage has characteristics of the periosteum (Shibata et al, ).…”

Immunohistochemistry for Matrix Proteins in newly formed Mandibular Condylar Cartilage in a Human Fetus

“…Furthermore, we have examined expression patterns of collagen types I, II and X in human cranial base cartilage which undertook endochondral ossification at 16 weeks of gestation [12]. Since digit cartilage in the present study did not undertake endochondral ossification, collagen type X immunoreactivity was very weak, but expression patters of these collagen types were similar to those in cranial base cartilage at 16 weeks of gestation, indicating these collagen types have universal function in developing human long bones.…”

“…We also demonstrated that chondrocytes in initially formed condylar cartilage is rapidly differentiated into hypertrophic chondrocytes, and simultaneously expresses many kinds of matrix components including collagen types I, II, X, aggrecan, versican, hyaluronan, bone sialoprotein and osteopontin [7][8][9][10][11]. In human, we demonstrated that the newly formed condylar cartilage is continuous with the ossifying mandible [8], and also demonstrated that immunohistochemical localization of matrix proteins in already formed condylar cartilage in midterm fetuses [12]. However, no immunohistochemical studies have been done in newly formed condylar cartilage in human.…”

“…Biotinated hyaluronan (HA)-binding protein (25 mg/ml) was from Seikagaku corp. (Tokyo, Japan). These antibodies and HA binding protein were used in our previous immunohistochemical studies [7,[10][11][12]14,15]. Mouse monoclonal anti-human alkaline phosphatase antibody (diluted 1:25) was from R&D systems (Minneapolis, MN, USA).…”

“…Alkaline phosphatase epitopes were retrieved by incubating the sections in 10 mol/L citrate buffer (pH 6.0) at 100 ̊C for 5 min. The Histofine SAB kit (Nichirei, Tokyo, Japan) was used to perform streptavidin-biotin labeling as previously described [7,[10][11][12]14,15]. The sections were treated with 3-amino-9-ethylcarbazole to visualize protein localization.…”