Pulmonary Response After Exposure to Inhaled Nickel Hydroxide Nanoparticles: Short and Long-term Studies in Mice

Short and long-term pulmonary response to inhaled nickel hydroxide nanoparticles (nano-Ni(OH)(2), CMD = 40 nm) in C57BL/6 mice was assessed using a whole body exposure system. For short-term studies mice were exposed for 4 h to nominal concentrations of 100, 500, and 1000 mg/m(3). For long-term studies mice were exposed for 5 h/d, 5 d/w, for up to 5 months (m) to a nominal concentration of 100 mg/m(3). Particle morphology, size distribution, chemical composition, solubility, and intrinsic oxidative capacity were determined. Markers of lung injury and inflammation in bronchoalveolar lavage fluid (BALF); histopathology; and lung tissue elemental nickel content and mRNA changes in macrophage inflammatory protein-2 (Mip-2), chemokine ligand 2 (Ccl2), interleukin 1-alpha (Il-1α), and tumor necrosis factor-alpha (Tnf-α) were assessed. Dose-related changes in BALF analyses were observed 24 h after short-term studies while significant changes were noted after 3 m and/or 5 m of exposure (24 h). Nickel content was detected in lung tissue, Ccl2 was most pronouncedly expressed, and histological changes were noted after 5 m of exposure. Collectively, data illustrates nano-Ni(OH)(2) can induce inflammatory responses in C57BL/6 mice.