Immunohistochemistry of collagen types II and X, and enzyme-histochemistry of alkaline phosphatase in the developing condylar cartilage of the fetal mouse mandible
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.(Accepted July 29 1997)
Key Words: Bone; periosteum; chondrocytes.
c1 Correspondence to Dr Shunichi Shibata, 1st Department of Oral Anatomy, School of Dentistry, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113, Japan. Tel: 03-5803-5436; fax: 03-5803-0185; e-mail: S.Shibata.email@example.com