When something causes an increased expression of degradative enzymes, then the balance tips toward a net loss of cartilage, via loss of proteoglycans and collagen.
They initially start making less of the proteoglycans and more Type II collagen, but soon switch over to making a different collagen type, type I collagen.
Unfortunately, type I collagen doesn't interact with the proteoglycans in the same way and there is an overall decrease in elasticity in the cartilage matrix, allowing it to breakdown.
The anchors of this framework are proteins called proteoglycans. And from each one sprouts lots and lots of long, starchy strands called glycosaminoglycans, or GAGs, radiating out from those proteins like brush bristles.