Effects of Myeloid Hif-1β Deletion on the Intestinal Microbiota in Mice under Environmental Hypoxia

External environmental factors can cause an imbalance in intestinal flora. For people living in the extremes of a plateau climate, lack of oxygen is a primary health challenge that leads to a series of reactions. We wondered how intestinal microorganisms might change in a simulated plateau environment and what changes might occur in the host organism and intestinal microorganisms in the absence of hypoxia-related factors. In this study, mice carrying a knockout of hypoxia-inducible factor 1β ( ) in myeloid cells and wild-type mice were raised in a composite hypoxic chamber to simulate a plateau environment at 5,000 m of elevation for 14 days. The mice carrying the myeloid deletion displayed aggravated hypoxic phenotypes in comparison to and significantly greater weight loss and significantly higher cardiac index values than the wild-type group. The levels of some cytokines increased in the hypoxic environment. Analysis of 16S rRNA sequencing results showed that hypoxia had a significant effect on the gut microbiota in both wild-type and -deficient mice, especially on the first day. The levels of members of the family increased continuously from day 1 to day 14 in deletion mice, and they represented an obviously different group of bacteria at day 14 compared with the wild-type mice. Butyrate-producing bacteria, such as , were found in wild-type mice only after 14 days in the hypoxic environment. In conclusion, hypoxia caused heart enlargement, greater weight loss, and obvious microbial imbalance in myeloid -deficient mice. This study revealed genetic and microecological pathways for research on mechanisms of hypoxia.