Comparison of the biological activity between ultrafine and fine TiO2 particles in raw 264.7 cells associated with oxidative stress.
Kang-JL; Moon-C; Lee-HS; Lee-HW; Park-E; Kim-HS; Castranova-V
Toxicologist 2008 Mar; 102(1):304-305
Ultrafine or fine TiO2 particles are widely used in the production of white pigments, sunscreens and cleanup techniques. However, currently the knowledge is deficient of cellular response to these particles. The study evaluated and compared the biological activity of ultrafine and fine TiO2 particles in RAW 264.7 macrophages according to an oxidative stress paradigm. We found that in vitro exposure of macrophages with ultrafine or fine TiO2 in the range of 0.5-100 microg/ml did not significantly alter cell viability. Ultrafine TiO2 enhanced intracellular generation of reactive oxygen species (ROS) to a greater extent than fine TiO2 at each exposure dose. Ultrafine TiO2 induced ERK1/2 activation in a dose-dependent man while the fine-TiO2-induced changes were minimal. Phosphorylation of ERK1/2 occurred following 10 min exposure to higher doses of ultrafine TiO2 (above 25 microg/ml). Similarly, ultrafine TiO2 exposure significantly enhanced TNFalpha and MIP- 2 secretion in a dose-dependent manner and its potency was higher than fine TiO2. These findings suggest that at relatively low doses of the particles, ultrafine TiO2 has greater biological activity associated with oxidative stress, such as ROS generation, ERK 1/2 activation, and proinflammatory mediator secretion, in RAW 264.7 macrophages than fine TiO2.
Particulates; Particulate-dust; Cell-biology; Cellular-reactions; Pigments; Sunscreening-agents; Biological-factors; Biological-monitoring; Biological-transport; Biological-effects; Biological-function; Oxidative-metabolism; Oxidative-processes; Chronic-exposure; Epidemiology; Cell-function; Biological-systems; Dust-exposure; Dust-particles; Particle-aerodynamics; Nanotechnology
The Toxicologist. Society of Toxicology 47th Annual Meeting and ToxExpo, March 16-20, 2008, Seattle, Washington