Prolonged Hyperbaric Exposure Alters Gut Mucus, Microbiota Composition And Intestinal Antimicrobial Defense In Mice

Abstract

PURPOSE Long‐time saturation exposure may induce anxiety, loss of appetite, and digestive disorders, which relate to impairment of intestinal mucosal immune system and gut microbiota homeostasis. Our study examined the effects of 4‐day of saturation exposure on gut microbiota and intestinal antimicrobial peptides (AMPs) in mice. METHOD 20 male C57 Mice, 8‐week old, were randomly divided into saturation exposure group (SE, n=10) and control group (CON, n=10). SE exposed to N2/O2 mixed gas at 500kPa for 4 days in pressure chamber. Intestines were excised and stained with HE and AB‐PAS. Feces and Intestines were collected and extract gDNA and RNA respectively. We used qPCR to assay bacterial population (Bacteroides, Clostridia, Lactobacilli, Enterobacteria, and Akkermansia muciniphila) of the feces, and the AMPs (Defα5/β1, Retnlβ, Reg3β/γ) of small intestine and colon. RESULTS Within 4 days, SE mice did not exhibit nitrogen narcosis behavior. By comparing with the 16S rRNA genes, results revealed a significant increase in the relative abundances of A. muciniphila (9.28±5.67) and Clostridia (3.45±0.63) in SE. The relative abundance of Lactobacilli was lower (0.40±0.24) in SE. Moreover, a distinct increase of Enterobacteria (23.34±8.88) was observed in SE compared with CON. Gene expressions for Defα5/β1 in SE were decreased in small intestine, while Defβ1 and Reg3γ in SE were significantly decreased, and Defα5 and Reg3β increased in colon. CONCLUSION In sum, the data showed that a four‐day saturation exposure induced changes in the mRNA level of AMPs, and the gut microbiota composition in mice. Found: NSFC 31471135