Adrenal deficiency alters mechanisms of neutrophil mobilization

Deficiency of adrenal hormones promotes exacerbated neutrophil influx into inflammatory sites. We investigated the effect of adrenal deficiency on neutrophil mobilization comparing adrenalectomized (ADX) male Wistar rats to sham-operated (SO) or non-manipulated (N) animals, as controls. Seven days after surgeries, the number of neutrophils in peripheral blood was increased in ADX rats, by accelerating neutrophil maturation steps in the bone marrow. The investigation of adhesive properties on neutrophil membranes indicated reduced and increased expressions of L-selectin on cells present in the bone marrow and circulating blood, respectively. Similar levels of L-selectin mRNA in both cells from ADX or non-manipulated rats suggest that these effects do not depend on gene expression. Even though no differences in the expression of β2 integrin by neutrophils were detected, modulation on subsequent PMN activation may occur by adrenal hormones, since circulating neutrophils from ADX exhibit lower in vitro adherence to the endothelium. We conclude that adrenal hormones control the adhesive interactions of neutrophils with the bone marrow microenvironment and with the vascular endothelium chiefly by modulation of L-selectin on PMN membrane in a mechanism independent of L-selectin gene expression.