clinical trial
Regolith Chemical Toxicity: Silicate Reactivity and Oxidative Stress Mechanisms in EVA Workers
Dr. Chen Wei
· Lunar Medical Research Cooperative
Lunar Toxicology · Vol. 2, No. 1 · January 25, 2029
Abstract
Lunar regolith is chemically reactive in ways that distinguish it from terrestrial silicates. Unweathered silicates present high surface reactivity and generate reactive oxygen species on contact with biological tissue. We characterize the toxicity mechanisms and evaluate antioxidant prophylaxis in a controlled pilot study.
Terrestrial silicosis — pulmonary fibrosis from crystalline silica inhalation — provides an imperfect model for lunar regolith toxicity. Lunar regolith differs in critical ways: the absence of billions of years of weathering leaves the silicate surfaces chemically reactive, with dangling chemical bonds that generate reactive oxygen species (ROS) on contact with water, biological fluid, or tissue.
This ROS generation mechanism is likely the primary driver of the dose-response relationship we and others have documented between EVA exposure and respiratory inflammation markers.
In this 12-week pilot study, 30 EVA workers were randomized to N-acetylcysteine 600mg twice daily (antioxidant) or placebo. Exhaled breath condensate H₂O₂ (a marker of airway oxidative stress) decreased by 28% in the NAC group relative to placebo. Subjective respiratory symptoms also decreased.
We recommend a confirmatory trial with larger sample size and longer follow-up before NAC is added to standard EVA prophylaxis protocols. The biological plausibility is strong, and the intervention is low-cost and well-tolerated.
This ROS generation mechanism is likely the primary driver of the dose-response relationship we and others have documented between EVA exposure and respiratory inflammation markers.
In this 12-week pilot study, 30 EVA workers were randomized to N-acetylcysteine 600mg twice daily (antioxidant) or placebo. Exhaled breath condensate H₂O₂ (a marker of airway oxidative stress) decreased by 28% in the NAC group relative to placebo. Subjective respiratory symptoms also decreased.
We recommend a confirmatory trial with larger sample size and longer follow-up before NAC is added to standard EVA prophylaxis protocols. The biological plausibility is strong, and the intervention is low-cost and well-tolerated.
Keywords
regolith, silicate, reactive oxygen species, oxidative stress, NAC, antioxidant, toxicology