A quantitative chemical study of glycosaminoglycans in the articular disc of the bovine temporomandibular joint.

Glycosaminoglycans were prepared from the disc by digestion with papain. The disc contained 5% of its dry weight as glycosaminoglycan. Fractionation by ion-exchange chromatography, followed by precipitation at varying concentrations of ethanol, together with chemical and enzymatic analyses, showed this glycosaminoglycan to consist of approx. 5% hyaluronic acid, 14% dermatan sulphate, 79% chondroitin sulphate and 2% keratan sulphate. Disaccharides obtained from the chondroitin sulphate were 75% 6-sulphated, 21% 4-sulphated and 4% non-sulphated. Chemical analysis showed a low average degree of sulphation of chondroitin sulphate. Immunohistochemical staining of sagittal sections of the disc showed chondroitin sulphate to be distributed throughout, whereas dermatan sulphate (as proteodermatan sulphate) appeared to be concentrated in the periphery.