GROWTH OF CARTILAGE EXPLANTS BIOCHEMICAL AND TENSILE BIOMECHANICAL PROPERTIES

Articular cartilage mechanical properties and biochemical composition evolve during in utero development and in vivo growth, with marked differences between the fetus, newborn, and young adult. The objective of this study was to esbblish an in vino system to asses the fartors that regulate such growth, in particular by characterizing the growth of fetal and newborn bovine articular cartilage explants during 6 weeks of freeswelling rulture in serunksupplemented medium. During this culture period, both fetal and calf cartilage grew markedly in sue, increasing in cell and matrix components. While the tensile modulus, strength and stiffness of calf cartilage were initially higher than those of fetal cartilage, the tensile properties of both types of cartilage explants fell, to similarly Im levels, during the cnlture period. The increase in cells and matrix, but diminution rather than increase in tensile properties, suggests that regulatory factors other than serum, may trigger the biomechanical maturation of articular cartilage in vivo.