Cerium oxide nanoparticle aggregates affect stress response and function in Caenorhabditis elegans

OBJECTIVE: The continual increase in production and disposal of nanomaterials raises concerns regarding the safety of nanoparticles on the environmental and human health. Recent studies suggest that cerium oxide (CeO(2)) nanoparticles may possess both harmful and beneficial effects on biological processes. The primary objective of this study is to evaluate how exposure to different concentrations (0.17–17.21 µg/mL) of aggregated CeO(2) nanoparticles affects indices of whole animal stress and survivability in Caenorhabditis elegans. METHODS: Caenorhabditis elegans were exposed to different concentrations of CeO(2) nanoparticles and evaluated. RESULTS: Our findings demonstrate that chronic exposure of CeO(2) nanoparticle aggregates is associated with increased levels of reactive oxygen species and heat shock stress response (HSP-4) in Caenorhabditis elegans, but not mortality. Conversely, CeO(2) aggregates promoted strain-dependent decreases in animal fertility, a decline in stress resistance as measured by thermotolerance, and shortened worm length. CONCLUSION: The data obtained from this study reveal the sublethal toxic effects of CeO(2) nanoparticle aggregates in Caenorhabditis elegans and contribute to our understanding of how exposure to CeO(2) may affect the environment.