| Low oxygen conditions in the high-altitude environment may damage the intestine and lead to the disorder of intestinal flora.Probiotics can regulate the disorder of intestinal flora,enhance the body’s immunity and maintain the function of intestinal mucosal barrier.This study explored the effects of Lactobacillus johnsonii BS15 on intestinal flora of mice in the low oxygen conditions of the high altitude environment.Thirty-six C57BL/6J mice were randomly divided into three groups.They were divided into Control group,the High altitude group(HA)and the High altitude fed with probiotics group(HAP),respectively.And the HA and HAP were exposed for 14 days in a simulated low-pressure oxygen chamber at an altitude of 3000～3500 m.And each mouse in HAP group was given 0.2 m L Lactobacillus johnsonii BS15 bacterial solution(1×10~9CFU/m L)every day,and the other groups were fed the same amount of PBS buffer.At the end of the trial,determine the antioxidant capacity and diamine oxidase(Diamine oxidase;DAO)and D-lactate levels in serum.And collected the ileum for intestinal tissue damage detection and miRNA sequencing analysis.The intestinal flora was analyzed by high-throughput sequencing.The results are as follows:1.The detection of serum oxidative stress related indicators showed that the low oxygen conditions in the high-altitude environment led to increased oxidative stress level and decreased antioxidant capacity in mice.The increase of serum intestinal mucosal barrier integrity damage markers indicates that the low oxygen conditions in the high-altitude environment destroyed the intestinal barrier.The detection of the related indicators of ileum inflammation showed that the low oxygen conditions in the high-altitude environment led to the occurrence of ileum inflammation in mice.Lactobacillus johnsonii BS15 supplementation improved these symptoms.2.The results of intestinal microflora diversity analysis showed that the low oxygen conditions in the high-altitude environment increased the richness and diversity of intestinal microflora in mice.From the results of Principal Coordinates Analysis(PCo A)and the changes of intestinal flora at the phylum,family and genus levels,it was shown that the low oxygen conditions in the high-altitude environment led to changes in the structure of intestinal flora in mice.Lactobacillus johnsonii BS15 supplementation reversed the above changes and restored the gut microbiota structure.3.The results of the LEfSe analysis are indicated,the biomarkers in the HAP group were Lactobacillus,Bacteroides,S24-7,Erysipelothrix,Desulfovibrio and Bifidobacterium,and which were Lactobacillus,Erysipelothrix,Isobibacter,Coriobacteriaceae,S24-7,Desulfovibrio and Bifidobacterium in Control group.The HA group biomarkers are Bacillus,Staphylococcus.4.Indicator species analysis showed that the dominant bacteria were Coriobacteriaceae,Lactobacteriaceae,S24-7 and Erysipelotichaceae in Control group and HAP group.And that were Coriobacteriaceae in HAP group and HA group.While the Control group and HA group had no obvious common dominant flora.5.The results of the miRNA analysis of the ileal expression showed,the miR-122-5p showed a high correlation with miR-196b-5p,miR-5114,miR-196a-5p,as well as miR-196a-1-3p.Compared with the Control group,11 miRNAs were up-regulated and 11miRNAs were down-regulated in the HA group;4 miRNAs were up-regulated and five miRNAs were down-regulated in HAP group.Compared with HA group,8 miRNAs were up-regulated and 5 miRNAs were down-regulated in HAP group.Meanwhile,the differentially expressed miRNA target gene prediction is shown that the target genes are mainly enriched in cellular processes,biological processes,the regulation of cellular processes,the regulation of biological processes,and the cellular response to stimuli.And the KEGG pathways are mainly enriched in pathways such as olfactory transduction,cancer pathway,mitogen-activated protein kinase signaling pathway,and Adenosine Monophosphate activated protein kinase pathway.In conclusion,the mice were exposed for 14 days in the low oxygen conditions in the high-altitude environment of 3000～3500 m,reduced oxidation resistance,disrupted the intestinal mucosal barrier integrity,and change the structure of the intestinal flora in mice.And the Lactobacillus johnsonii BS15 could alleviate the effects of the low oxygen conditions in the high-altitude environment on the intestinal microflora to some exten. |
