Speaker
Description
Proton radiation dominates space radiation (∼90%) and threatens deep space missions, yet its effects on gut microbiota at mission-relevant doses (0.1-1 Gy) are unclear. This study assessed impacts in BALB/c mice exposed to whole-body proton irradiation (0, 0.1, or 1 Gy; 100 MeV cyclotron). Fecal samples (day 3 post-irradiation) underwent 16S rRNA sequencing. Results revealed a dose threshold: 1 Gy induced significant structural remodeling, marked by increased Firmicutes (56.93% vs. control 32.23%), decreased Bacteroidetes (3.95% vs. 27.95%), a 116% higher Firmicutes/Bacteroidetes ratio, and enrichment of biomarkers Lachnospiraceae NK4A136 (LDA=4.2) and denitrifiers (LDA=3.8). Conversely, 0.1 Gy caused minor changes (Rikenellaceae, LDA=3.5; Odoribacter, LDA=3.3). Critically, 1 Gy enhanced alpha diversity (Chao1 +15-20%, Shannon +11.3%; p<0.05) and altered beta diversity (R²=0.251-0.361, p<0.05) versus controls. Functional prediction (PICRUSt2) identified disruptions in cellular processes/signaling (p=0.0133), poorly characterized pathways (p=0.0298), ABC transporters (K03088, p=0.021), and fatty acid metabolism (K02003, p=0.045). These findings demonstrate that gut microbiota exhibits differential dose-response patterns to proton radiation, which provide both reference biomarkers and mechanistic insights for evaluating astronaut intestinal health risks and developing microbiota-targeted countermeasures during deep space missions.
Funding Agency
Supported by CNNC Basic Research Foundation CNNC-JCYJ-202313
