Usefulness of dietary flaxseed in abrogating lung damage associated with space exploration: antioxidant and anti‐inflammatory effects of flaxseed in a murine model of repeated double‐hit low‐level radiation and hyperoxia exposure

Crew members during spaceflight missions must conduct extra‐vehicular activities (EVA) which may expose them to lung damaging hyperoxia and low levels cosmic/galactic radiation. Flaxseed (FS) has lung protective properties in mouse models of acute and chronic lung injury. To test the usefulness of FS as a dietary supplement for such missions, we evaluated FS in a murine model of double‐hit hyperoxia and radiation. Mouse cohorts (n=5/group) were pre‐fed diets containing either 0% FS or 10% FS for 3 wks and exposed to: a) normoxia; b) >95% O 2 (O 2 ); c) 0.25Gy gamma radiation (RAD); or d) a combination of O 2 and RAD (O 2 +RAD). Challenge (O 2 or RAD) was given 3X weekly for 2 wks; 8‐hour hyperoxia was spanned by normoxic intervals. Lungs were evaluated for oxidative damage, inflammation, injury and fibrosis. 0% FS‐fed mice developed significant lung injury and inflammation across all challenges, as evidenced by bronchoalveolar lavage (BAL) neutrophils (p<0.003), BAL protein levels and increased oxidative tissue damage (p<0.008). Lung hydroxyproline content increased in 0% FS‐fed mice exposed to RAD and O 2 +RAD (p<0.001). All adverse effects due to challenge conditions were ameliorated in FS‐fed mice. In conclusion, dietary FS is protective in a murine model of repeated low‐level radiation and hyperoxia exposure. Funded by: NIH/NCI, NASA (MCS)Grant Funding Source : NIH/NCI/NASA