The differentiation and calcification of chondrocytes in primary cell cultures.

: The cartilage from a non-immobilized fracture undergoes a series of morphological and biochemical changes resembling the in vivo differentiation and calcification in the epiphyseal plate. The studies reported here demonstrate that a homogeneous population of chondrocytes isolated from fracture callus fibrocartilage undergoes the same changes in vitro. Chondrocyte primary cultures were grown for 28 days during which time the morphological, histological and histochemical properties of the cultures were studied. Demonstrated by various histological procedures, chondrocytes synthesized the characteristic cartilage matrix, and progressively calcified with increased culture age. This system can be used to elucidate the cellular and molecular mechanisms of calcification.