Acute toxicity and biodistribution of different sized titanium dioxide particles in mice after oral administration

In order to evaluate the toxicity of TiO₂ particles, the acute toxicity of nano-sized TiO₂ particles (25 and 80 nm) on adult mice was investigated compared with fine TiO₂ particles (155 nm). Due to the low toxicity, a fixed large dose of 5 g/kg body weight of TiO₂ suspensions was administrated by a single oral gavage according to the OECD procedure. In 2 weeks, TiO₂ particles showed no obvious acute toxicity. However, the female mice showed high coefficients of liver in the nano-sized (25 and 80 nm) groups. The changes of serum biochemical parameters (ALT/AST, LDH) and pathology (hydropic degeneration around the central vein and the spotty necrosis of hepatocytes) of liver indicated that the hepatic injury was induced after exposure to mass different-sized TiO₂ particles. In addition, the nephrotoxicity like increased BUN level and pathology change of kidneys was also observed in the experimental groups. The significant change of serum LDH and alpha-HBDH in 25 and 80 nm groups showed the myocardial damage compared with the control group. However, there are no abnormal pathology changes in the heart, lung, testicle (ovary), and spleen tissues. Biodistribution experiment showed that TiO₂ mainly retained in the liver, spleen, kidneys, and lung tissues, which indicated that TiO₂ particles could be transported to other tissues and organs after uptake by gastrointestinal tract.