AbstractBilateral medial meniscectomy was undertaken in 14 mature beagles. Another two underwent arthrotomy (sham‐operated controls). One week after surgery, six of the meniscectomised animals were administered glycosaminoglycan polysulphate (Arteparon) (2 mg/kg) subcutaneously three times a week for 3 weeks, then twice weekly until killed 23 weeks later. Two months before death all animals were given Na235SO4(1.0 mCi/kg) intravenously. At autopsy, articular cartilage (AC) from the medial and lateral compartments, as well as from the femoral trochlear groove and femoral head, was sampled. Proteoglycans (PGs) were isolated by 4.0MGuanidine hydrochloride (GuHCI) extraction of AC and purified by ultracentrifugation. The PG monomers were assayed for hexuronic acid, protein, and hexosamines (galactosamine/glucosamine), and their ability to aggregate. The results indicated that Arteparon provided some protective effect to AC in the menisectomised compartment as demonstrated histologically by reduced surface fibrillation, diminished chondrocyte cloning, and maintence of alcianophilia. The levels of PGs and hexuronate‐protein ratios in medial AC of drug‐treated meniscectomised animals were found to be comparable to sham controls, whereas these parameters in the nondrug‐treated meniscectomized group were de