AGE-CHANGES IN THE RAT TEMPOROMANDIBULAR-JOINT ARTICULAR DISC - A BIOCHEMICAL-STUDY ON GLYCOSAMINOGLYCAN CONTENT

The temporomandibular joint (TMJ) articular discs were removed from fe male Sprague-Dawley rats 3, 5, 10, 32, 90 and 130 weeks of age. Glycos aminoglycans (GAGs) were extracted from the discs by heat treatment, a lkali treatment and digestion with Pronase E, and purified by precipit ation with cetylpyridinium chloride and ethanol. The concentration of total GAG was highest in the 3 week extracts and tended to decrease wi th age. Dermatan sulphate was the predominant GAG detected in all age groups along with chondroitin sulphate, hyaluronic acid and heparan su lphate. The disaccharides obtained from chondroitin sulphate were Delt a Di-4S, Delta Di-6S and Delta Di-0S, with Delta Di-4S being the predo minant isomer followed by Delta Di-6S for all ages of all the GAG exam ined. The concentration of chondroitin sulphate showed a decrease with age. Quantitative changes of GAG with age may be related to functiona l changes in TMJ discs.