Effects of Titanium Dioxide Nanoparticles Isolated from Confectionery Products on the Metabolic Stress Pathway in Human Lung Fibroblast Cells

Abstract

Titanium dioxide (TiO 2) is a common additive in many foods, pigments, personal care products, and other consumer products used in daily life. Despite the widespread use of nanoscale TiO 2 and composites of nanoscale TiO 2 in the food industry, there is a serious lack of awareness of the toxicity of TiO 2 nanoparticles (NPs) among consumers and manufacturers. There is an urgent need for toxicological studies of TiO 2 NPs. TiO 2 food additives separated from marketed foods were characterized by transmission electron microscopy. In addition, the effects of TiO 2 NPs on metabolic stress in WI-38 cells were analyzed. Cell viability, total ROS, mitochondrial transmembrane potential (ΔψM), cell cycle, and metabolism-related gene expression were analyzed. The results indicate that TiO 2 NPs have a significant concentration-dependent toxic effect in lung cells. The ΔψM, the intracellular ROS level, and the stages of the WI-38 cell cycle were altered by increasing TiO 2 concentrations after exposure for 24 and 48 h relative to the control. Cytochrome P450 1A, GSTM3, and glutathione S-transferase A4 upregulation in response to the TiO 2 NPs was observed. These findings suggest that the toxicity of TiO 2 from confectionery products in WI-38 cells may be mediated through an increase in oxidative stress. The results of this study clearly demonstrate the nanotoxicological effects of TiO 2 on WI-38 cells and will be useful for nanotoxicological indexing.