title: Chondrocytes synthesize type I collagen and accumulate the protein in the matrix during development of rat tibial articular cartilage.
abstract: The present study was designed to investigate whether or not chondrocytes in articular cartilage express type I collagen in vivo under physiological conditions. Expressions of the gene and the phenotype of type I collagen were examined in rat tibial articular cartilage in the knee joint during development. Knee joints of Wistar rats at 1, 5, and 11 weeks postnatal were fixed in 4% paraformaldehyde with or without 0.5% glutaraldehyde and decalcified in 10% EDTA. After the specimens were embedded in paraffin and serial sections made, adjacent sections were processed for immunohistochemistry and in situ hybridization for type I collagen. The epiphysis of the tibia was composed of cartilage in week- 1 rats. Formation of articular cartilage was in progress in week 5 as endochondral ossification proceeded and was completed in week 11. Anti-type I collagen antibody stained only the superficial area of the epiphysis in week 1, but the immunoreactivity was expanded into the deeper region of the articular cartilage with development in weeks 5 and 11. Hybridization signals for pro-alpha 1 (I) collagen were seen in some of chondrocytes in the epiphysis of the week-1 tibia. The most intense signals were identified in chondrocytes in week 5 and the signals appeared weaker in week 11. The present study demonstrated that chondrocytes synthesize type I collagen and accumulate the protein in the matrix during development of the articular cartilage.
authors.affiliation: Second Department of Oral Anatomy, Tohoku University School of Dentistry, Sendai, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sasano
authors.forename: M
authors.initials: M
authors.lastname: Furusawa
authors.forename: H
authors.initials: H
authors.lastname: Ohtani
authors.forename: I
authors.initials: I
authors.lastname: Mizoguchi
authors.forename: I
authors.initials: I
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Kagayama
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D002358:Cartilage, Articular / Q000737:chemistry* / Q000166:cytology / Q000254:growth & development; D003094:Collagen / Q000096:biosynthesis* / Q000235:genetics; D004838:Epiphyses / Q000737:chemistry / Q000196:embryology; D005109:Extracellular Matrix / Q000737:chemistry* / Q000235:genetics; D006132:Growth Plate / Q000737:chemistry; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007719:Knee Joint / Q000737:chemistry / Q000196:embryology*; D051381:Rats; D017208:Rats, Wistar; D013977:Tibia / Q000196:embryology*
chemical_list: D003094:Collagen