Human recombinant lipocortin 1 has acute local anti-inflammatory properties in the rat paw edema test

Human recombinant lipocortin 1 has been tested for anti-inflammatory activity in a conventional model of acute inflammation. Microgram amounts of the protein, locally administered, inhibited edema of the rat paw when induced by subplantar injections of carrageenin: the ED50 was 10-20 micrograms per paw, and inhibition (maximum of 60-70%) was not dependent upon an intact adrenal cortex. Doses of lipocortin that produced approximately 50% inhibition in the carrageenin test were inactive against edema elicited by bradykinin, serotonin, platelet-activating factor-acether, or dextran, whereas edema caused by Naja mocambique venom phospholipase A2 was strongly inhibited by lipocortin. The protein inhibited edema when rats were pretreated with agents that depleted mast-cell amines, kininogen, or polymorphonuclear leukocytes prior to initiation of the carrageenin edema but had no inhibitory action when rats were pretreated with the dual cyclooxygenase/lipoxygenase inhibitor BW 755C. These results demonstrate that human recombinant lipocortin has potent local anti-inflammatory activity, probably through selectively interfering with eicosanoid generation. Lipocortin is relatively ineffective against edema caused by mast-cell degranulation or kinins, except when degranulation is caused by phospholipase A2.