Influence of Different Sizes of Titanium Dioxide Nanoparticles on Hepatic and Renal Functions in Rats with Correlation to Oxidative Stress

Abstract

As titanium dioxide (TiO₂) nanoparticles are widely used commercially, the potential effects of TiO₂ nanoparticles on humans are a concern. To evaluate the effects of TiO₂ nanoparticles on hepatic and renal functions and correlate changes to oxidative stress, Sprague-Dawley rats were treated with TiO₂ particles of two different specific surface areas (TiO_2-S50: 50 m²/g, and TiO_2-S210: 210 m²/g) at 0.5, 5, or 50 mg/kg body weight by intratracheal instillation. After 7 d, TiO₂ nanoparticles produced no obvious acute toxicity on hepatic and renal functions. However, superoxide dismutase (SOD) activity of plasma and glutathione peroxidase (GSH-PX) activity of kidney in the low-dose TiO_2-S210 group were significantly decreased. After TiO_2-S210 exposure, malondialdehyde (MDA) levels of liver and kidney in intermediate and high-dose groups were significantly increased. This change only appeared in liver after TiO_2-S50 exposure. Furthermore, SOD activity in liver and kidney and GSH-PX activity in kidney with low TiO_2-S210 exposure group were significantly less than with low TiO_2-S50. No apparent pathological changes in liver and kidney were observed. Intratracheal exposure to TiO₂ nanoparticles may induce oxidative stress in liver and kidney, but does not influence hepatic or renal functions. There was no apparent evidence that TiO_2-S210 was more toxic than TiO_2-S50. In general, intratracheal exposure to TiO₂ did not markedly affect extrapulmonary tissue functions.