THE CELLULAR INFLAMMATORY STRESS RESPONSE GENERATED BY SELECT MARTIAN, LUNAR AND ASTEROIDAL METEORITE SAMPLES – IMPLICATION FOR HUMAN SPACE EXPLORATION

Whether for economic, explorative, or survival reasons humans are likely to visit nearby planetary bodies for extended periods of time. The three most likely candidates for exploration are the Moon, Mars, and Vesta. One of the risks associated with extended human exploration of these planetary bodies is the inadvertent and repeated exposure to dust. Assessment of inhalation exposure risk to human explorers is complicated by the fact that these planetary bodies all have been exposed to space weathering, which leads to alteration of primary minerals. One research strategy is to study the toxicity of simulants. An alternative approach is to study available planetary material.

In this study, the oxidative stress generated by selected meteorite samples is examined and compared to terrestrial mid-ocean ridge basalt (MORB). The primary marker utilized in the study is the cellular inflammatory stress response (ISR) of A549 human lung epithelial cells, defined as the cellular upregulation of ROS (indicator of future apoptosis) normalized by cellular viability (necrosis). The MORB is non-reactive and generated the lowest ISR, followed by the Vesta HED meteorites (NWA 2060 and Berthoud), which are also essentially non-reactive. Only one of the lunar meteorites (NWA 4734) is reactive, while the second one (NWA 7611) generates in ISR lower than the HED meteorites. Both Martian meteorite samples (NWA 7034 and Tissint) generated a significant ISR, with NWA 7034 generating a response similar to terrestrial soil contaminated with high levels of trace elements (NIST 2710).

The ISR generated by the Martian meteorite samples is likely due to their higher iron contents. Although more samples (primary, secondary or simulants) are needed in order to fully understand the hazards at the surface of each planetary body, the meteorite samples selected offer a basis for evaluating the risk of human exploration to these types of planetary bodies.