In vivo evaluation of induction of acute oxidative stress by metal oxide nanoparticles

Metal oxide nanoparticles are one of important industrial nanomaterials. Metal oxide nanoparticles have using for many industrial uses such as electronics components and catalysis. Recently, it is suggested that solubility of metal oxide nanoparticles is important for its cytotoxic activity on in vitro examinations. On the other hand, interaction of metal ion release and in vivo toxicity, particularly induction of oxidative stress, is still unclear. In the present study, acute biological influences were examined by rat intratracheal instillation of nano- and fine-scale nickel oxide (NiO) and titanium dioxide (Ti02). NiO and TiO2 particle were dispersed in water containing 5 % fetal bovine serum as a dispersant. The NiO nanoparticles dispersion included approximately 60 g/ml of nickel ion. Moreover, nickel chloride (NiC12) solution (60 g/m1) was also administrated as soluble nickel. Intratracheal instillation of these dispersions or solution to rat was performed (0.2 mg/rat). Then bronchoalveolar lavage fluid (BALF) was collected from 1 hour, 1 day, 3 days and 1 week after instillation. Lung injury and oxidative stress levels were examined. NiO nanoparticles and NiC12 induced lung injury and oxidative stress. On the other ahnd, NiO fine-particles and TiO2 particles did not induce injury and oxidative stress in rat lung. These results suggest that solubility of metal oxide nanoparticles is important factor of their toxic activity at least acute phase.