Intestinal microbiota contributes to altered glucose metabolism in simulated microgravity mouse model

Exposure to space environment induces alterations in glucose and lipid metabolism that contribute to muscular atrophy, bone loss, and cardiovascular disorders. Intestinal microbiota is also changed, but its impact on spaceflight-related metabolic disorder is not clear. We investigated the relationship between glucose metabolic changes and gut dysbiosis in a hind limb-unloading (HU) mouse model, a well-accepted ground-based spaceflight analog. Impaired body weight gain, glucose intolerance, and peripheral insulin resistance were found in 2-4-wk HU mice. Reduced abundance of gut Bifidobacterium spp. and Akkermansia muciniphila was observed within 3 d of HU. The ground-based control (Ctrl) mice that were cohoused with HU mice showed similar patterns of dysbiosis and metabolic changes. Compared with the Ctrls, higher levels of plasma LPS-binding protein and altered transcription of Tnfa and glucose metabolism-related genes in the liver were observed in HU mice. The supplementation of Bifidobacterium spp. suppressed endotoxemia and liver inflammation and improved glucose tolerance in HU mice. The results indicate a close relationship between dysbiosis and altered glucose metabolism in the HU model and also emphasize the importance of evaluating intestinal microbiota in astronauts and its effect on glucose metabolism.-Wang, Y., Zhao, W., Shi, J., Wang, J., Hao, J., Pang, X., Huang, X., Chen, X., Li, Y., Jin, R., Ge, Q. Intestinal microbiota contributes to altered glucose metabolism in simulated microgravity mouse model.