Granulocyte and plasma cytokine activity in acute cadmium intoxication in rats

Abstract

Changes in the number and ex vivo function of peripheral blood neutrophils were investigated following intraperitoneal administration of cadmium-chloride in rats. Besides a dose-dependent increase in the number of peripheral blood neutrophils, changes were found in the functional state of isolated polymorphonuclear leukocytes (PMNs). Increased spontaneous adhesion and activation, and TNF activity in a conditioned medium were observed in cultures of granulocytes in comparison to granulocytes from control (saline-treated) animals. Increased levels of plasma activity of inflammatory cytokines, tumor necrosis factor (TNF) and interleukin-6 (IL-6) were noted following cadmium administration. Cytological signs of pulmonary inflammation were revealed histologically and the majority of neutrophils recovered from the lungs by enzyme digestion exhibited a capacity of nitroblue tetrazolium (NBT) reduction. Our data demonstrate that acute cadmium intoxication leads to a systemic inflammatory response characterized by numerical and functional changes in the granulocyte compartment and to increased levels of inflammation-related cytokine activity in the circulation. Correlations between the increased number of peripheral blood neutrophils and IL-6 plasma activity (r = 0.776, p < 0.00001) and the number of neutrophils recovered from the lung tissue (r = 0.893, p < 0.00001) suggested that systemic cadmium-induced inflammation might be involved in the pulmonary toxicity of cadmium.