| Summary: | Discs of articular cartilage from the humeral heads of adult goats have been compressed in vitro by a method which allows diffusion of liquid and solutes into the matrix. The ability of the chondrocytes to incorporate [35]S sulphate into glycosaminoglycans during mechanical loading has been examined both by autoradiography and after the chemical separation of the labelled matrix components. Static loads of greater than 15 kg./cm.[2] were sufficient to inhibit synthesis almost completely. Fluctuating loads of 50 kg./cm.[2] only partially inhibited sulphate incorporation. In both the loaded and unloaded specimens, most of the radioactivity was associated with the chondroitin sulphate. The cartilage was able to recover most of its ability to manufacture chondroitin sulphate after 2h. continuous compression by loads of 50 kg./cm.[2]. Chondrocytes were isolated from their matrix by enzymic digestion and cultivated for periods of up to 21 days in a chemically defined medium. The cell population remained constant or increased slightly during this period. By the twelfth day, the cells, which had originally been randomly dispersed, had become aggregated into clumps. The appearances of the cell cultures at various stages were examined both by light and by scanning electron microscopy. The cells incorporated sulphate and proline. Small quantities of hydroxyproline were produced. The synthesis of sulphated glycosaminoglycans was not inhibited by the addition of chondroitin sulphate to the medium. Cells were isolated from the calcified matrix of cancellous bone of adult goats and osteoarthritic humans by partial decalcification in ethylenediamine tetraacetic acid (E.D.T.A.) followed by enzymic digestion. The isolated cells fluoresced brilliantly when stained with Euchrysine 3R and viewed by transmitted fluorescent illumination, The cells also excluded eosin. The isolated bone cells were cultivated for periods of up to four weeks. The cells clumped during cultivation, and the population remained constant. Osteoclasts could be identified after four weeks cultivation. The isolated cells Incorporated [14]C labelled proline and hydroxylated small quantities of it.
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