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.