Asian dust and titanium dioxide particlesinduced inflammation and oxidative DNA damage in C57BL/6 mice

Inhaled particulate matter (PM) might influence many adverse health effects in human body, including increased exacerbations of pulmonary and cardiovascular diseases. In this study, we examined the associations between PM and pulmonary adverse effects. Two types of particles, Asian dust (AD) and titanium dioxide (TiO2), were administered intratracheally to C57BL/6 mice. The mice were exposed to saline and saline suspensions of 20mg/kg of AD, TiO2 particles twice a week for 12 weeks. Following exposure with these particles, the lungs were analyzed histopathologically by hematoxylin and eosin (H&E) and Masson's trichrome (MT) staining. Oxidative injuries were determined by immunohistochemistry (IHC) for 8-oxoguanine in the lungs and Comet assays in peripheral blood mononuclear cells (PBMCs) of C57BL/6 mice. Mice exposed to AD and TiO2 showed significant inflammatory changes and oxidative damages in the lungs as compared with the control group. DNA damage in PBMCs was also increased significantly in AD and TiO2-exposed mice. However, lung fibrosis was minimal and there was no significant difference between PM exposed and control mice. Exposure to AD and TiO2 particlesinduced similar inflammatory damages in the lungs and elicited oxidative DNA damage in the PBMCs.