What happens when the cartilage matrix breaks down?
A decrease in the number or length of GAG chains has serious effects on the cartilage tissue. One effect is that the reduced chain length leads to reduced binding with collagen. This allows the remaining GAGs to separate more widely and imbibe more water. A second and related effect is that when GAG molecules occupy less of the matrix volume there is more space for water. These two changes result in a softer, more watery matrix, which has less resiliency and less tensile strength. This soft matrix is more easily damaged by normal wear and tear, which leads in turn to a degraded environment for the cartilage cells. The damaged chondrocytes are more likely to produce abnormal GAGs, and so a vicious cycle is established, leading eventually to joint breakdown. Although science does not know exactly what starts matrix breakdown, we do know several factors that can predispose to it, including wear and tear to cartilage, chronic joint overuse, abnormal loading of joint surfaces, use of steroi
