Immunohistochemistry of collagen types II and X, and enzyme‐histochemistry of alkaline phosphatase in the developing condylar cartilage of the fetal mouse mandible

Abstract

We investigated the immunohistochemical localisation of types II and X collagen as well as the cytochemical localisation of alkaline phosphatase in the developing condylar cartilage of the fetal mouse mandible on d 14-16 of pregnancy. On d 14 of pregnancy, although no immunostaining for types II and X collagen was observed, alkaline phosphatase activity was detected in all cells in the anlage of the future condylar process. On d 15 of pregnancy, immunostaining for both collagen types was simultaneously detected in the primarily formed condylar cartilage. Alkaline phosphatase activity was also detected in chondrocytes at this stage. By d 16 of pregnancy, the hypertrophic cell zone rapidly increased in size. These findings strongly support a periosteal origin for the condylar cartilage of the fetal mouse mandible, and show that progenitor cells for condylar cartilage rapidly or directly differentiate into hypertrophic chondrocytes.

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

“…Another most narrow definition is that it arises from the periostea of membrane bone after (secondary to) bone formation [2,5,6]. We have demonstrated that newly formed condylar cartilage is derived from alkaline phosphatase-positive periosteum-like tissue, and supported this definition in mice and rats [7,8]. 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].…”

“…We have demonstrated that newly formed condylar cartilage is derived from alkaline phosphatase-positive periosteum-like tissue, and supported this definition in mice and rats [7,8]. 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].…”

“…We have previously described that rodent mandibular condylar cartilage derives from alkaline phosphatase-positive periosteum-like tissue continuous with the ossifying mandible [7,8], supporting the narrow definition of secondary cartilage that it arises from the periostea of membrane bone. In human fetus, a general histologic study demonstrated that the condylar cartilage formed continuous with the ossifying mandible, and postulate this narrow definition may be applied for human condylar cartilage [8].…”

“…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.…”