Crystal-induced inflammation, enzyme release and the effects of drugs in the rat pleural space.

The pleural space of the rat has been used to study the acute inflammatory response to crystals of monosodium urate monohydrate, calcium pyrophosphate dihydrate and hydroxyapatite. Each crystal caused a brisk inflammatory response accompanied by crystal phagocytosis and release of lysosomal enzymes. These responses were modified by the anti-inflammatory drugs indomethacin, dexamethasone, colchicine and cyclophosphamide. The results of these experiments suggesting that the resting cell population of the pleural space contributed to the response, and that lysosomal enzyme release may play only a minor role in the mediation of increased vascular permeability.