Neurotoxicity Study with Titanium Dioxide Nanoparticles on Rat

Abstract

Numerous studies have shown titanium dioxide nanoparticles (TiO2 NPs) could present a risk or potential risk to humans and other living organisms in certain conditions via inhalation and skin contact. Dermal exposure has limited adverse effects and the possible risks for exogenous inhaled nanoparticles migrating to the brain through the olfactory nerve is still under research. To study the in vivo and in vitro neurotoxicity of brain tissue in rats induced by TiO2 NPs. For in vitro study, rat astrocytes were exposed to TiO2 NPs with three different diameters (10, 50 and 200 nm) at five concentrations levels. Cellular morphology and sulfur rhodamine B (SRB) were carried out to evaluate the viability of particle-treated cells after 72 hours exposure. For in vivo study, suspensions of test material above mentioned were injected into tracheas of Wistar rats at dose of 0.1, 1.0 and 10.0 mg·kg-1 in three groups, respectively. After 72 hours of exposure, the concentration of TiO2 NPs in brain tissue and the levels of IL-1β, TNF-α and IL-10 in brain homogenate were measured, while the cell morphology induced by TiO2 NPs was observed by light microscopy and transmission electron microscopy. TiO2 NPs can significantly affect the growth and morphology of rat astrocytes and inhibit the proliferation of astrocytes, which was positively related to dose-effect and size-dependent response. Pathological observations indicated that TiO2 NPs could penetrate the blood-brain barrier, leading to blood-brain barrier damage in rats, brain tissue necrosis, mitochondrial swelling and apoptosis while the non-nanoscale TiO2 particles showed no significant toxicity in the central nervous system cells.