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 inflammatory processes including autoimmune diseases. However, the influence of low-dose glucocorticoids on the respiratory burst activity of neutrophils has not been studied. The aim of this work was to study the effect of treatment with low-dose prednisone on the oxidative burst of rat peripheral blood neutrophils. Wistar male rats were treated with prednisone by gavage (28, 87 or 257 μg/animal/day) for 7 or 15 days. These doses are equivalent to 10, 30 or 90 mg/adult human (∼70 kg)/day, respectively. Sera from normal rats were used to opsonize zymosan (opZy). Neutrophils (1×10⁵) were stimulated by opZy and the oxidative burst of control or treated rat cells was measured by luminol-dependent chemiluminescence (CL). Prednisone did not affect the CL of rat neutrophils for either period of treatment, or any studied doses, when compared with controls. These results suggest that the low-dose prednisone has no effect on the oxidative burst mediated by complement receptors during the rat neutrophil phagocytosis of complement-opZy.