Comparison of collagenase activity in eosinophil and neutrophil fractions from rat peritoneal exudates

The collagenase activity had been compared in extracts of eosinophils and of neutrophilss from peritoneal exudates in two groups of rats, one of which had been treated to augment the numbers of eosinophils and the other the numbers of neutrophils. The proportion of granulocytes to other cells in each preparation was increased by differential centrifugation over a continuous gradient. Collagenase was extracted from the fractions in which granulocytes were concentrated and the activity assayed by the radioactive fibril method. There was at least as much collagenase in the eosinophil-enriched extracts as in the neutrophil-enriched extracts. It is postulated that eosinophil collagenase may have a function in the remodelling of newly-synthesised collagen during the post-inflammatory phase of healing, since eosinophil leucocytes appear in significant numbers within the connective tissue during this phase. This suggests a different role for eosinophil collagenase than that for neutrophil collagenase, since neutrophil are present only in the early stages of inflammation, when collagen is being degraded.