Calf Articular Cartilage in Organ Culture in a Chemically Defined Medium. 2. Concentrations of Glycosaminoglycans and [35S]-sulfate Incorporation at Different Oxygen Tensions

Articular cartilage from 6-month-old calves was maintained in organ culture in Eagle's minimum essential medium at different oxygen tensions between 20 and 50%. When well standardized cartilage pieces of about 1 mm thickness were used the results showed a high degree of reproducibility. The glycosaminoglycans were studied using the cetylpyridinium chloride cellulose and epichlorohydrin triethanolamine (ECTEOLA) column techniques on a microscale. In some experiments the cartilage was labelled with [35S]sulfate. Small alterations of the concentrations and distribution of different glycosaminoglycans were found and were not affected by various oxygen tensions for up to 4 weeks. A small increase was found in the fractions containing low molecular weight chondroitin sulfate. Devitalized cartilage, maintained under identical conditions, remained largely unaltered during the 4 weeks. The [35S]sulfate activity calculated per mole of hexosamine showed a general decrease during culture maintenance. High specific activities in the fractions containing low molecular weight chondroitin sulfate and keratan sulfate were found between 1 and 3 weeks of maintenance in 20% oxygen. Maintenance in 50% oxygen resulted in severely disturbed synthesis of glycoaminoglycans. The results are interpreted as showing that the synthesis pattern of glycosaminoglycans in articular cartilage can be altered by other factors and without the prior loss of glycosaminoglycans.