Effects of 60 days of 6° head-down bed rest on the composition and function of the human gut microbiota

Spaceflight is rigorous and dangerous environment which can negatively affect as-tronauts' health and the entire mission. The 60 days of 6 degrees head-down bed rest (HDBR) experiment provided us with an opportunity to trace the change of gut mi-crobiota under simulated microgravity. The gut microbiota of volunteers was analyzed and characterized by 16S rRNA gene sequencing and metagenomic sequencing. Our results showed that the composition and function of the volun-teers' gut microbiota were markedly was affected by 60 days of 6 degrees HDBR. We further confirmed the species and diversity fluctuations. Resistance and virulence genes in the gut microbiota were also affected by 60 days of 6 degrees HDBR, but the spe-cies attributions remained stable. The human gut microbiota affected by 60 days of 6 degrees HDBR which was partially consistent with the effect of spaceflight, this implied that HDBR was a simulation of how spaceflight affects the human gut microbiota.

Automated summary

The 60-day experiment of 6 degrees head-down bed rest provided an opportunity to study the change of gut microbiota under simulated microgravity. Through sequencing and analysis, it was found that the composition, function, species diversity, and the presence of resistance and virulence genes in the gut microbiota of volunteers were significantly affected. This indicates that head-down bed rest can serve as a simulation of how spaceflight affects the human gut microbiota.