Degradation of cartilage matrix by purified elastase and its control by an endogenous purified specific cartilage elastase inhibitor.

UNLABELLED: We report here that an endogenous protein in cartilage is capable of inhibiting leukocyte elastase degradation of cartilage matrix. This inhibitor is specific for elastase. After 30 min of incubation, small amounts of the purified elastase are capable of releasing relatively large amounts of uronic acid positive material and relatively small amounts of collagenous and noncollagenous protein. The hydrolytic effectiveness of elastase is exemplified by its action on various natural substrates. This action, however, is inhibited by a specific natural elastase inhibitor purified from cartilage. INTRODUCTION: The extracellular matrix of cartilage is responsible for the resiliency, tensile strength plus ion and water binding ability of this tissue. Any modification in the arrangement or composition of proteoglycans, collagen and glycoproteins found in the cartilage matrix affects these properties. Such modification can be derived by the action of hydrolytic enzymes originating from chrondrocytes or from cells attracted in the cartilage area by chemotaxis.