Antioxidant and anti-genotoxic properties of cerium oxide nanoparticles in a pulmonary-like cell system

Cerium oxide nanoparticles (CeO2-NP) present two different oxidation states what can suppose an auto-regenerative redox cycle. Potential applications of CeO2-NP to quench reactive oxygen species (ROS) in biological systems are currently being investigated. In this context, CeO2-NP may represent a novel agent to protect cells and tissues against oxidative damage by its regenerative free radical-scavenging properties. In this study, we have used a human epithelial lung cell line, BEAS-2B, as a model to study the possible antioxidant and anti-genotoxic effect of CeO2-NP in a pulmonary-like system. We have assessed the protective effect of CeO2-NP pre-treatment in front of a well-defined oxidative stress-inducing agent (KBrO3). Different endpoints like toxicity, intracellular ROS induction, genotoxicity and DNA oxidative damage (comet assay), and gene expression alterations have been evaluated. The obtained results confirmed the antioxidant properties of CeO2-NP. Thus, its pre-treatment significantly reduced the intracellular production of ROS induced by KBrO3. Similarly, a reduction in the levels of DNA oxidative damage, as measured with the comet assay complemented with formamidopyrimidine DNA glycosylase enzyme, was also observed. Pre-treatment of BEAS-2B cells with CeO2-NP (at 2.5 µg/mL) slightly increased the viability of cells treated with KBrO3 as well as down-regulated the expression of the Ho1 and Sod2 genes involved in the oxidative Nrf2 pathway. Our finding would support the potential usefulness of CeO2-NP as a pharmacological agent to be used against diseases caused by oxidative stress.