Comparative Hepatotoxicity of Inhaled Cadmium Chloride and Cadmium Oxide

Abstract

The toxicity of inhaled aerosols of cadmium chloride (CdCl2) and cadmium oxide (CdO) on hepatic biochemical function was compared. Male rats were exposed for 2 hours to concentrations of 0.45 and 4.5 mg Cd/m3. Serum and liver enzymes and histological changes were studied immediately and 72 hours after exposure. Exposure to 4.5 mg/m3 CdCl2 and CdO resulted in an increase in liver Cd content. This deposition was not observed at the lower concentrations. Following exposure to 4.5 mg/m3 CdCl2, decreases in body and liver weight, as well as decreased activities of glutathione (GSH)-reductase, GSH-peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PDH) were observed. Increases in serum bilirubin and activities of creatine kinase, lactate dehydrogenase, and aspartate aminotransferase were evident 72 hours after exposure. Exposure to 4.5 mg/m3 CdO caused decreased activities of GSH-reductase and peroxidase, G-6-PDH, and an increased activity of serum alkaline phosphatase and lactate dehydrogenase. Exposure to 0.45 mg/m3 CdCl2, produced more hepatic effects than did a similar exposure to CdO. This differential response between inhalation of CdCl2 and CdO was probably due to a rapid clearance of CdCl2 or Cd2+ ions from the lung and transport to the liver via the systemic blood circulation.