Potential pulmonary toxic effects of Martian dust simulant

Human exploration of the Moon and Mars will inevitably result in exposure to extraterrestrial dust. We investigated the potential pulmonary toxicity of JSC Mars-1(Martian dust simulant, respirable diameter 1.45 μm) using an advanced multicellular lung mucosa model with dust applied apically to human bronchial epithelial cells cultured at the air-liquid interface, with doses 55, 222, and 890 μg/cm2, PBS (sham). Compared to the sham, medium and high doses of JSC Mars-1 increased necrosis-related gene HMGB1 expression. The cellular total reactive oxygen species (ROS) levels increased in a dose-dependent manner. The expression of antioxidant-related genes, HMOX-1 and SOD3, increased at all dose levels. Interleukin-6 (IL-6) protein and gene expression increased, and tumor necrosis factor alpha (TNF-α) after high dose. CXCL8 mRNA was elevated at medium and high doses. TLR4 surface and gene expression decreased at medium and high doses. JSC Mars-1 dust increased cytotoxicity, oxidative stress, and immune responses suggesting potential pulmonary toxic effects, providing insight to molecular mechanisms behind potential adverse respiratory effects.