Oral administration of nano-titanium dioxide particle disrupts hepatic metabolic functions in a mouse model

TiO₂ nano-particle (TiO₂ NP) is widely used in industrial, household necessities, as well as medicinal products. However, the effect of TiO₂ NP on liver metabolic function has not been reported. In this study, after mice were orally administered TiO₂ NP (21nm) for 14days, the serum and liver tissues were assayed by biochemical analysis, real time quantitative polymerase chain reaction, western blot and transmission electron microscopy. The serum bilirubin was increased in a dose dependent manner. Deposition of TiO₂ NP in hepatocytes and the abnormality of microstructures was observed. Expression of metabolic genes involved in the endogenous and exogenous metabolism was modified, supporting the toxic phenotype. Collectively, oral administration of TiO₂ NP (21nm) led to deposition of particles in hepatocytes, mitochondrial edema, and the disturbance of liver metabolism function. These data suggested oral administration disrupts liver metabolic functions, which was more sensitive than regular approaches to detect material hepatotoxicity. This study provided useful information for risk analysis and regulation of TiO₂ NPs by administration agencies.