A radioassay for proteolytic cleavage of isolated cartilage proteoglycan. 2. Inhibition of human leukocyte elastase and cathepsin G by anti-inflammatory drugs.

20 non-steroidal anti-inflammatory drugs and other agents were evaluated for their effectiveness in directly inhibiting the proteolytic activity of human leukocyte elastase and cathepsin G. The proteolysis of hide powder azure by leukocyte granule extracts was used for initial testing, and selected drugs were then studied further using a radioassay of the proteolysis of isolated proteoglycan by purified leukocyte elastase and cathepsin G. The results indicated that at drug concentrations likely to be attained to vivo, phenylbutazone may significantly inhibit elastase, while gold thiomalate and mucopolysaccharide polysulfonic acid ester (MPSE; Arteparon) could limit the action of cathepsin G. Oleic acid may provide a useful starting point for development of agents specifically designed to inhibit cartilage erosion.