Cellular stages in cartilage formation as revealed by morphometry, radioautography and type II collagen immunostaining of the mandibular condyle from weanling rats.

摘要: The role played by cell addition, enlargement, and matrix deposition in the endochondral growth of condyle was assessed weanling rats four approaches making use light microscope: morphometry, 3H-thymidine radioautography, 3H-proline immunostaining for cartilage-specific type II collagen. From articular surface down, may be divided into five layers made up cells embedded a matrix: 1) layer composed static rich fibers presumed to I collagen, 2) polymorphic including progenitor from which arise undergoing changes, 3) flattened produce precartilagenous devoid collagen while differentiation two stages: "chondroblast" stage short "flattened chondrocyte" when intracellular elaboration begins, 4) upper hypertrophic layer, are "typical chondrocytes" that enlarge at rapid rate, actively deposit it cartilagenous matrix, 5) lower chondrocytes terminal enlargement is adapting mineralization. radioautographic results indicate turnover time about 2.9 days. spent each development estimated 1.4 days as chondroblasts, 0.5 chondrocytes, 2.3 1.1 those layer. Calculations referring 1 x 1-mm square-sided column extending zone vascular invasion provide daily rate addition (0.0077 mm3), extracellular (0.0127 (0.0302 mm3). Hence respective contribution three factors ratio 1:1.6:4. This result emphasizes overall condyle.