Neutrophil enzyme activities in carrageenan-induced inflammation in rats

During the course of carrageenan-induced inflammation in rats major changes were observed in the activities of neutrophil granule enzymes. The activities of three enzymes--gelatinase, collagenase and beta-glucuronidase, the markers of three different types of granules, have been measured and compared to those of a control group of animals. Total collagenase and gelatinase activities of control rats were 59.4 +/- 3.6 (mean +/- SD) and 23.0 +/- 2.9 units/mg protein, respectively. Significantly reduced levels of both collagenase (35.6 +/- 2.5 units) (p less than 0.05) and gelatinase (7.1 +/- 0.7 units) (p less than 0.001) were measured in the blood neutrophils of inflamed rats; and the collagenase activity of neutrophils derived from inflamed pleural exudate was also significantly decreased to a level of 19.7 +/- 1.8 units/mg protein (p less than 0.01). However, the gelatinase activity of exudate neutrophils did not differ from that of blood cells of inflamed rats. In contrast, no change was found for the beta-glucuronidase activity in blood neutrophils of control and inflamed rats. These observations support the concept that during the inflammatory response in rats, neutrophils in the circulation may become activated as judged by the extracellular secretion of collagenase and gelatinase. Therefore, neutrophils accumulating in acute inflammatory lesions contain decreased levels of collagenolytic enzymes and the significance of this observation is discussed.