The immunotoxicity of three nickel compounds following 13-week inhalation exposure in the mouse

Abstract

Groups of B6C3F 1 mice were exposed to aerosols of nickel subsulfide (Ni 3S 2), nickel oxide (NiO), or nickel sulfate hexahydrate (NiSO 4·6H 2O) 6 hr/day, 5 days per week for 65 days to determine the immunotoxicity of these compounds. Exposure concentrations were 0.11, 0.45, and 1.8 mg Ni/m 3 for Ni 3S 2, 0.47, 2.0, and 7.9 mg Ni/m 3 for NiO; and 0.027, 0.11, and 0.45 mg Ni/m 3 for NiSO 4. Thymic weights were decreased only in mice exposed to 1.8 mg Ni/m 3 Ni 3S 2. Increased numbers of lung-associated lymph nodes (LALN), but not spleen nucleated cells, were seen with all compounds. Nucleated cells in lavage samples were increased in mice exposed to the highest concentrations of NiSO 4 and NiO and to 0.45 and 1.8 mg Ni/m 3 Ni 3S 2. Increased antibody-forming cells (AFC) were seen in LALN of mice exposed to 2.0 and 7.9 mg Ni/m 3 NiO and 1.8 mg Ni/m 3 Ni 3S 2. Decreased AFC 10 6 spleen cells were observed in mice exposed to NiO, and decreased AFC/spleen were seen for mice exposed to 1.8 mg Ni/m 3 Ni 3S 2. Only mice exposed to 1.8 mg Ni/m 3 Ni 3S 2 had a decrease in mixed lymphocyte response. All concentrations of NiO resulted in decreases in alveolar macrophage phagocytic activity, as did 0.45 and 1.8 mg Ni/m 3 Ni 3S 2. None of the nickel compounds affected the phagocytic activity of peritoneal macrophages. Only 1.8 mg Ni/m 3 Ni 3S 2 caused a decrease in spleen natural killer cell activity. Results indicate that inhalation exposure of mice to nickel can result in varying effects on the immune system, depending on dose and physicochemical form of the nickel compound. These nickel-induced changes may contribute to significant immunodysfunction.