Abstract
Summary
A neutral protease fraction of human PMN granules which degrades elastin and hydrolyzes l-alanine p-nitrophenyl ester (NBA) was tested on rabbit articular cartilage. Forty micrograms of this fraction released 568 μg of protein from 10 mg of cartilage in 4 hr (average value of five experiments). This effect was correlated with a nearly complete loss of metachromatic staining of the cartilage ground substance. Electrophoretically purified pancreatic elastase also degraded cartilage matrix, supporting the suggestion that the elastinolytic protease of the PMN granule fraction was primarily responsible for its attack upon matrix proteoglycan. Another fraction of the granules, containing only collagenolytic activity but no NBA-esterolytic activity, gave insignificant matrix degradation. Of 15 human, pathologic synovial fluid samples, seven contained readily measurable NBA-esterase activity.
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