Suppression of DNCB-induced irritant dermatitis by colchicine.

In vivo effects of colchicine on DNCB-induced primary irritant dermatitis in guinea-pigs were investigated with simultaneous evaluation of in vitro chemotactic activity of polymorphonuclear leukocytes (PMNs). Colchicine, 125, 250 and 500 microgram/kg, was injected intraperitoneally 1 hour prior to the painting of 20 microliter of 10% DNCB in acetone on shaved dorsum of the animals. In the control animals, erythema and induration were maximum and dermal PMN infiltration was most intense at 24 hours. In the colchicine-treated animals, induration--but not erythema--was reduced, with sparse dermal PMN infiltration. In vitro chemotaxis of PMNs from cardiac blood to LPS-treated serum using Boyden chamber techniques revealed maximal suppression of the activity in the colchicine injected animals at 12 hours. It is suggested that the reduced induration and decreased infiltration of PMNs in the inflammatory tissue in the colchicine-injected animals are caused by prior suppression of locomotion of PMNs in the peripheral blood.