EFFECT OF HYDROCORTISONE ON OXYGEN-FREE RADICAL GENERATION BY MONONUCLEAR-CELLS

Corticosteroids are known to exert antiinflammatory and immunosuppress ive effects. Since reactive oxygen species (ROS) induce tissue damage and inflammation and since mononuclear cells (MNCs) generate ROS, we i nvestigated whether corticosteroids inhibit ROS generation by MNCs whe n given systemically. A single dose of either 300 mg (n = 8) or 100 mg (n = 6) of hydrocortisone (HC) was injected intravenously into eight and six subjects, respectively. Blood samples were obtained before and sequentially after the injection. Following 300 mg HC, N-formylmethio nyl leucyl phenylalanine (fMLP)-induced ROS generation, assayed by mea suring chemiluminescence with luminol, decreased significantly at 0.5 hours and reached a nadir at 2 hours (8% of basal, P < .001); thereaft er, it gradually recovered, but was still below baseline at 24 hours. Following the dose of 100 mg HC, ROS generation decreased significantl y at 1 hour (nadir, 30% of basal; P < .01) and gradually recovered to near basal level at 8 hours. Serum cortisol concentrations were marked ly elevated over basal and remained elevated throughout the first 8 ho urs of the experiment returning to baseline at 24 hours. This inhibiti on of ROS generation by HC land other glucocorticoids) may have a role to play in mediating the antiinflammatory action of corticosteroids. Copyright (C) 1998 by W.B. Saunders Company.