Effect of low-dose prednisone in vivo on the ability of complement receptor to mediate an oxidative burst in rat neutrophils

Glucocorticoids have been used in the treatment of a variety of inflammator y processes including autoimmune diseases. However, the influence of low-do se glucocorticoids on the respiratory burst activity of neutrophils has not been studied. The aim of this work was to study the effect of treatment wi th low-dose prednisone on the oxidative burst of rat peripheral blood neutr ophils. Wister male rats were treated with prednisone by gavage (28, 87 or 257 mu g/animal/day) for 7 or 15 days. These doses are equivalent to 10, 30 or 90 mg/adult human (similar to 70 kg)/day, respectively. Sera from norma l rats were used to opsonize zymosan (opZy). Neutrophils (1 X 10(5)) were s timulated by opZy and the oxidative burst of control or treated rat cells w as measured by luminol-dependent chemiluminescence (CL). Prednisone did not affect the CL of rat neutrophils for either period of treatment, or any st udied doses, when compared with controls. These results suggest that the lo w-dose prednisone has no effect on the oxidative burst mediated by compleme nt receptors during the rat neutrophil phagocytosis of complement-opZy. (C) 2000 Elsevier Science B.V. All rights reserved.