Kinetics of collagenase and neutral protease release by neutrophils exposed to microcrystalline sodium urate.

The rates of release of the various enzymes from PMN leukocytes exposed to MSU crystals were measured. Lysozyme and neutral protease appeared to be released simultaneously and release appeared to be essentially complete by 60 minutes. In contrast, collagenase was detected only after 30 minutes incubation, reached peak concentration at 90 minutes and dropped noticeably by 180 minutes. The presence of these enzymes was not due to cell lysis since only 10% of the total cellular LDH was present in the supernates. The levels of total and active collagenase in the supernatants were measured. In contrast to latent collagenase, active collagenase levels increased continually throughout the incubation period. The gradual increase in level of active collagenase may explain the corresponding drop of latent collagenase in the longer incubation (90 minutes or more) as the latter apparently is converted to active form. The effects of collagenase on Type I collagen were examined by SDS gel electrophoresis.