Crystal-induced inflammation in canine joints. I. An experimental model with quantification of the host response.

Injection of sodium urate or calcium pyrophosphate crystals into the stifle joints of anesthetized dogs almost invariably induced an acute exudative response. This response was quantified by serial measurements of intra-articular pressure, pH and leukocyte concentration. Pressure rose progressively and reflected intra-articular volume increase. The hydrogen ion concentration increased as the reaction progressed and correlated in a given exudate with the leukocyte concentration. Analysis of sequential physiologic and biochemical changes occurring in this model of crystal-induced inflammation may provide insight into the mechanisms of acute gouty arthritis in man.