Toxicity of TiO2 nanoparticles on the NRK52E renal cell line

Titanium dioxide nanoparticles are widely used in industry to produce a number of products (cosmetics, paints, foods). TiO2 nanoparticles form aggregates and their toxicity varies in function of their size. In this study, aggregate sizes were determined using dynamic light scattering (DLS). The stability of the suspension was evaluated by turbidimetry and the size by transmission electronic microscopy (TEM). In the present study the toxicity of TiO2 nanoparticles was evaluated in vitro on rat kidney proximal tubular cells (NRK-52E). Cells were exposed to TiO2 nanoparticles (20 mu g/mL) for 24, 48, 72 and 96 hours. TiO2 nanoparticles induce the production of reactive oxygen species (ROS). The relative number of mitosis decreased, while an increase of apoptotic cells was noted. The number of S-phase cells evidenced by BrdU immunoreactivity in cultures was significantly reduced by the exposure to the nanoparticles. These results attest to the toxic effect of the TiO2 nanoparticles on NRK-52E cells.