[Action of sodium hyaluronate on embryonic chondrogenesis in Pleurodeles (author's transl)]

Sodium hyaluronate, present in large quantities during cellular multiplication and the migration phase, is not found in the extracellular matrix during early chondrocyte differentiation. Microinjections enabled a higher concentration of hyaluronate to be maintained than in normal embryos. This leads to the appearance of anomalies in the cartilage structure; these are always reversible and more or less marked according to the amount of hyaluronate injected and to the timing of the injection. If the injection is made as soon as differentiation takes place, or after it, a decrease of chondroïtine-sulfate excretion is observed. As these molecules are responsible for the differentiated state of chondrocytes, hyaluronate appears to be an extracellular substance that regulates chondrogenesis.