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Space Environmental Factor Impacts upon Murine Colon Microbiota and Mucosal Homeostasis.

Ritchie LE, Taddeo SS, Weeks BR, Lima F, Bloomfield SA, Azcarate-Peril MA, Zwart SR, Smith SM, Turner ND - PLoS ONE (2015)

Bottom Line: Spaceflight increased Clostridiales and decreased Lactobacillales, and similar trends were observed in the experiment using a ground-based model of microgravity, suggesting altered gravity may affect colonic microbiota.Although we noted no differences in colon epithelial injury or inflammation, spaceflight elevated TGFβ gene expression.Microbiota and mucosal characterization in these models is a first step in understanding the impact of the space environment on intestinal health.

View Article: PubMed Central - PubMed

Affiliation: Intercollegiate Faculty of Genetics, Texas A&M University, College Station, Texas, United States of America.

ABSTRACT
Astronaut intestinal health may be impacted by microgravity, radiation, and diet. The aim of this study was to characterize how high and low linear energy transfer (LET) radiation, microgravity, and elevated dietary iron affect colon microbiota (determined by 16S rDNA pyrosequencing) and colon function. Three independent experiments were conducted to achieve these goals: 1) fractionated low LET γ radiation (137Cs, 3 Gy, RAD), high Fe diet (IRON) (650 mg/kg diet), and a combination of low LET γ radiation and high Fe diet (IRON+RAD) in male Sprague-Dawley rats; 2) high LET 38Si particle exposure (0.050 Gy), 1/6 G partial weight bearing (PWB), and a combination of high LET38Si particle exposure and PWB in female BalbC/ByJ mice; and 3) 13 d spaceflight in female C57BL/6 mice. Low LET radiation, IRON and spaceflight increased Bacteroidetes and decreased Firmicutes. RAD and IRON+RAD increased Lactobacillales and lowered Clostridiales compared to the control (CON) and IRON treatments. Low LET radiation, IRON, and spaceflight did not significantly affect diversity or richness, or elevate pathogenic genera. Spaceflight increased Clostridiales and decreased Lactobacillales, and similar trends were observed in the experiment using a ground-based model of microgravity, suggesting altered gravity may affect colonic microbiota. Although we noted no differences in colon epithelial injury or inflammation, spaceflight elevated TGFβ gene expression. Microbiota and mucosal characterization in these models is a first step in understanding the impact of the space environment on intestinal health.

No MeSH data available.


Related in: MedlinePlus

Relative abundance (%) of bacterial taxa at the order level in the feces of rats resulting from exposure to high dietary iron or low LET radiation (Experiment 1).Actual values in S2 Table.
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pone.0125792.g001: Relative abundance (%) of bacterial taxa at the order level in the feces of rats resulting from exposure to high dietary iron or low LET radiation (Experiment 1).Actual values in S2 Table.

Mentions: We observed a significant radiation effect on the Clostridiales order (q = 0.17, S2 Table), with CON having a significantly higher proportion of Clostridiales compared to RAD and IRON+RAD (both q = 0.14, Fig 1). IRON+RAD had a significantly higher abundance of Unknown OTUs within the Bacteroidetes phylum compared to CON, RAD, and IRON groups (q<0.2, S2 Table). We observed no significant differences in species diversity (Shannon Weaver index) in response to dietary iron level, irradiation or their interaction (Table 1). Although not statistically significant, species richness (Chao index) was numerically higher in IRON+RAD rats compared to IRON rats (Table 1). Additionally, we observed relatively large changes in the following phylogenetic taxa that did not reach significance after adjusting for multiple comparisons. The abundance of Firmicutes was lower in the RAD group compared to CON (S2 Table). IRON rats tended to have an increased proportion of Bacteroidetes (17%) and decreased proportion of Firmicutes (31%) compared to CON. RAD elevated Lactobacillales with IRON+RAD having a higher proportion compared to CON and IRON.


Space Environmental Factor Impacts upon Murine Colon Microbiota and Mucosal Homeostasis.

Ritchie LE, Taddeo SS, Weeks BR, Lima F, Bloomfield SA, Azcarate-Peril MA, Zwart SR, Smith SM, Turner ND - PLoS ONE (2015)

Relative abundance (%) of bacterial taxa at the order level in the feces of rats resulting from exposure to high dietary iron or low LET radiation (Experiment 1).Actual values in S2 Table.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470690&req=5

pone.0125792.g001: Relative abundance (%) of bacterial taxa at the order level in the feces of rats resulting from exposure to high dietary iron or low LET radiation (Experiment 1).Actual values in S2 Table.
Mentions: We observed a significant radiation effect on the Clostridiales order (q = 0.17, S2 Table), with CON having a significantly higher proportion of Clostridiales compared to RAD and IRON+RAD (both q = 0.14, Fig 1). IRON+RAD had a significantly higher abundance of Unknown OTUs within the Bacteroidetes phylum compared to CON, RAD, and IRON groups (q<0.2, S2 Table). We observed no significant differences in species diversity (Shannon Weaver index) in response to dietary iron level, irradiation or their interaction (Table 1). Although not statistically significant, species richness (Chao index) was numerically higher in IRON+RAD rats compared to IRON rats (Table 1). Additionally, we observed relatively large changes in the following phylogenetic taxa that did not reach significance after adjusting for multiple comparisons. The abundance of Firmicutes was lower in the RAD group compared to CON (S2 Table). IRON rats tended to have an increased proportion of Bacteroidetes (17%) and decreased proportion of Firmicutes (31%) compared to CON. RAD elevated Lactobacillales with IRON+RAD having a higher proportion compared to CON and IRON.

Bottom Line: Spaceflight increased Clostridiales and decreased Lactobacillales, and similar trends were observed in the experiment using a ground-based model of microgravity, suggesting altered gravity may affect colonic microbiota.Although we noted no differences in colon epithelial injury or inflammation, spaceflight elevated TGFβ gene expression.Microbiota and mucosal characterization in these models is a first step in understanding the impact of the space environment on intestinal health.

View Article: PubMed Central - PubMed

Affiliation: Intercollegiate Faculty of Genetics, Texas A&M University, College Station, Texas, United States of America.

ABSTRACT
Astronaut intestinal health may be impacted by microgravity, radiation, and diet. The aim of this study was to characterize how high and low linear energy transfer (LET) radiation, microgravity, and elevated dietary iron affect colon microbiota (determined by 16S rDNA pyrosequencing) and colon function. Three independent experiments were conducted to achieve these goals: 1) fractionated low LET γ radiation (137Cs, 3 Gy, RAD), high Fe diet (IRON) (650 mg/kg diet), and a combination of low LET γ radiation and high Fe diet (IRON+RAD) in male Sprague-Dawley rats; 2) high LET 38Si particle exposure (0.050 Gy), 1/6 G partial weight bearing (PWB), and a combination of high LET38Si particle exposure and PWB in female BalbC/ByJ mice; and 3) 13 d spaceflight in female C57BL/6 mice. Low LET radiation, IRON and spaceflight increased Bacteroidetes and decreased Firmicutes. RAD and IRON+RAD increased Lactobacillales and lowered Clostridiales compared to the control (CON) and IRON treatments. Low LET radiation, IRON, and spaceflight did not significantly affect diversity or richness, or elevate pathogenic genera. Spaceflight increased Clostridiales and decreased Lactobacillales, and similar trends were observed in the experiment using a ground-based model of microgravity, suggesting altered gravity may affect colonic microbiota. Although we noted no differences in colon epithelial injury or inflammation, spaceflight elevated TGFβ gene expression. Microbiota and mucosal characterization in these models is a first step in understanding the impact of the space environment on intestinal health.

No MeSH data available.


Related in: MedlinePlus