MAINTENANCE OF PHENOTYPIC PROPERTIES BY CHONDROCYTES CULTURED IN SUSPENSION

Sternal chondrocytes obtained from 13-day-old chick embryos could be cultured in suspension without any mechanical agitation for 8 weeks. The cells in suspension retained all characteristics of chondrocytes when examined from morphological, histochemical and biochemical points of view. The floating cells were round in shape, rich in Golgi apparatus-associated vesicles. Each cell was covered with a thin coat of matrix showing metachromasia when stained with toluidine blue. Autoradiographic studies suggested an active synthesis of proteochondroitin sulfates by the individual floating cells. The biochemical analyses revealed that the floating cells continued to synthesize type H proteochondroitin sulfate and type II collagen, both of which are known to be characteristic products of differentiated chondrocytes.