Assessing Toxicity and Nuclear and Mitochondrial DNA Damage Caused by Exposure of Mammalian Cells to Lunar Regolith Simulants

Previous missions to the lunar surface implicated potential dangers of lunar soil. In future explorations, astronauts may spend weeks or months on the Moon, increasing the risk of inhaling lunar dust. In an effort to understand the biological impact of lunar regolith, cell cultures derived from lung or neuronal cells were challenged with lunar soil simulants to assess cell survival and genotoxicity. Lunar soil simulants were capable of causing cell death and DNA damage in neuronal and lung cell lines, and freshly crushed lunar soil simulants were more effective at causing cell death and DNA damage than were simulants as received from the supplier. The ability of the simulants to generate reactive oxygen species in aqueous suspensions was not correlated with their cytotoxic or genotoxic affects. Furthermore, the cytotoxicity was not correlated with the accumulation of detectable DNA lesions. These results determine that lunar soil simulants are, with variable activity, cytotoxic and genotoxic to both neuronal and lung-derived cells in culture. Plain Language Summary Lunar dust adhering to their suits caused mild respiratory issues for Apollo astronauts returning from the Moon. Chronic or long-term effects of such dust exposure could be a problem for future missions. We assessed the cellular effects of exposure to terrestrial materials produced to mimic some aspects of lunar dust (simulants). We found significant cell toxicity in neuronal and lung cell lines in culture, as well as DNA damage associated with the exposure. Unexpectedly, these effects did not reflect the ability of the simulants to generate free radicals.