Demonstration of chondroitin sulphate and glycoproteins in articular cartilage matrix using periodic acid-Schiff (PAS) method.

Staining of articular cartilage by the periodic acid-Schiff (PAS) method was measured using microspectrophotometry. Standard PAS technique with 2 h oxidation produced a distinct Schiff reaction in the cartilage sections. The staining increased with depth of the articular cartilage demonstrating distribution of the glycoproteins. The modified PAS method included a second, longer periodic acid treatment, which made the uronic acid of glycosaminoglycans PAS-positive. The modified PAS method proved to be highly specific for chondroitin sulphate, which was determined from the samples with gas chromatography. A statistically significant correlation between the Schiff reactivity and galactosamine content of the sections was observed. It is concluded that for articular cartilage standard and modified PAS methods are useful procedures for demonstrating local changes of glycoproteins and chondroitin sulphate, respectively.