Hypertrophy is not a prerequisite for type X collagen expression or mineralization of chondrocytes derived from cultured chick mandibular ectomesenchyme. 1994

S Ekanayake, and B K Hall
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.

Meckel's cartilage in the avian mandible is a neural crest-derived permanent cartilage. To investigate whether chondrocytes that form Meckel's cartilage can be induced to undergo maturation and mineralization by manipulating the environment, we used in vitro micromass culture in which young embryonic mandibular ectomesenchymal cells were maintained at a high cell density (2 x 10(7) cells/ml) and treated with ascorbic acid (AA) or with dexamethasone and ascorbic acid (DEX + AA). Chondrogenesis and chondrocyte maturation were analyzed by histological, immunohistochemical and SDS/PAGE techniques. Chick mandibular ectomesenchymal cells from Hamburger and Hamilton (J. Morphol. 88:49-92, 1951) stage 21 (HH stage 21) chick embryos undergo chondrogenesis forming cartilage nodules when maintained under micromass culture conditions. These chondrocytes undergo maturation in response to AA but not DEX. Addition of AA to culture medium induced type X collagen expression by these chondrocytes. With prolonged culture, chondrocytes began to mineralize turning cartilage nodules into completely mineralized structures. There was no correlation between chondrocyte size and type X collagen expression. Small chondrocytes as well as large (hypertrophic) chondrocytes expressed type X collagen and then underwent mineralization. Co-treatment of cultures with DEX + AA caused reduction of chondrogenesis and inhibited chondrocyte maturation and mineralization seen with AA alone.

UI MeSH Term Description Entries
D006984 Hypertrophy General increase in bulk of a part or organ due to CELL ENLARGEMENT and accumulation of FLUIDS AND SECRETIONS, not due to tumor formation, nor to an increase in the number of cells (HYPERPLASIA). Hypertrophies
D007150 Immunohistochemistry Histochemical localization of immunoreactive substances using labeled antibodies as reagents. Immunocytochemistry,Immunogold Techniques,Immunogold-Silver Techniques,Immunohistocytochemistry,Immunolabeling Techniques,Immunogold Technics,Immunogold-Silver Technics,Immunolabeling Technics,Immunogold Silver Technics,Immunogold Silver Techniques,Immunogold Technic,Immunogold Technique,Immunogold-Silver Technic,Immunogold-Silver Technique,Immunolabeling Technic,Immunolabeling Technique,Technic, Immunogold,Technic, Immunogold-Silver,Technic, Immunolabeling,Technics, Immunogold,Technics, Immunogold-Silver,Technics, Immunolabeling,Technique, Immunogold,Technique, Immunogold-Silver,Technique, Immunolabeling,Techniques, Immunogold,Techniques, Immunogold-Silver,Techniques, Immunolabeling
D008334 Mandible The largest and strongest bone of the FACE constituting the lower jaw. It supports the lower teeth. Mylohyoid Groove,Mylohyoid Ridge,Groove, Mylohyoid,Grooves, Mylohyoid,Mandibles,Mylohyoid Grooves,Mylohyoid Ridges,Ridge, Mylohyoid,Ridges, Mylohyoid
D008648 Mesoderm The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube. Mesenchyme,Dorsal Mesoderm,Intermediate Mesoderm,Lateral Plate Mesoderm,Mesenchyma,Paraxial Mesoderm,Dorsal Mesoderms,Intermediate Mesoderms,Lateral Plate Mesoderms,Mesenchymas,Mesoderm, Dorsal,Mesoderm, Intermediate,Mesoderm, Lateral Plate,Mesoderm, Paraxial,Mesoderms, Dorsal,Mesoderms, Intermediate,Mesoderms, Lateral Plate,Mesoderms, Paraxial,Paraxial Mesoderms,Plate Mesoderm, Lateral,Plate Mesoderms, Lateral
D002113 Calcification, Physiologic Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts. Bone Mineralization,Calcification, Physiological,Physiologic Calcification,Mineralization, Bone,Physiological Calcification
D002356 Cartilage A non-vascular form of connective tissue composed of CHONDROCYTES embedded in a matrix that includes CHONDROITIN SULFATE and various types of FIBRILLAR COLLAGEN. There are three major types: HYALINE CARTILAGE; FIBROCARTILAGE; and ELASTIC CARTILAGE. Cartilages
D002452 Cell Count The number of CELLS of a specific kind, usually measured per unit volume or area of sample. Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D002478 Cells, Cultured Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others. Cultured Cells,Cell, Cultured,Cultured Cell
D002642 Chick Embryo The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching. Embryo, Chick,Chick Embryos,Embryos, Chick
D003094 Collagen A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH). Avicon,Avitene,Collagen Felt,Collagen Fleece,Collagenfleece,Collastat,Dermodress,Microfibril Collagen Hemostat,Pangen,Zyderm,alpha-Collagen,Collagen Hemostat, Microfibril,alpha Collagen

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