Cerium dioxide nanoparticles can interfere with the associated cellular mechanistic response to diesel exhaust exposure

The aim of this study was to compare the biological response of a sophisticated in vitro 3D co-culture model of the epithelial airway barrier to a co-exposure of CeO2 NPs and diesel exhaust using a realistic air–liquid exposure system. Independent of the individual effects of either diesel exhaust or CeO2 NPs investigation observed that a combined exposure of CeO2 NPs and diesel exhaust did not cause a significant cytotoxic effect or alter cellular morphology after exposure to diesel exhaust for 2 h at 20 μg/ml (low dose) or for 6 h at 60 μg/ml (high dose), and a subsequent 6 h exposure to an aerosolized solution of CeO2 NPs at the same doses. A significant loss in the reduced intracellular glutathione level was recorded, although a significant increase in the oxidative marker HMOX-1 was found after exposure to a low and high dose respectively. Both the gene expression and protein release of tumour necrosis factor-α were significantly elevated after a high dose exposure only. In conclusion, CeO2 NPs, in combination with diesel exhaust, can significantly interfere with the cell machinery, indicating a specific, potentially adverse role of CeO2 NPs in regards to the biological response of diesel exhaust exposure.

► First study to assess dual effects of diesel exhaust and cerium dioxide NPs.
► Cerium dioxide NPs interfere with the secondary toxicity of diesel exhaust.
► Cerium dioxide NPs could be advantageous fuel borne catalysts.