The mechanism of regulating renin angiotensin system in bronchial asthma based on intestinal flora
Objective To explore the role of the renin angiotensin system in asthma and intestinal microecology.Methods Twenty Balb/c female mice were randomized into control group,asthma group,antibiotics group and Lactica-seibacillus rhamnosus(LGG)group,5 in each group.The asthma mouse model was established through ovalbumin sensit-ization and excitation,and fresh broad-spectrum antimicrobial drugs were added into the drinking water for intestinal flora depletion.Hematoxylin-eosin staining was used to observe the pathological changes in the lung tissues of mice;flow cyto-metry to detect the Th1/2 ratio in the spleen;RT-PCR to detect the mRNA expressions of GATA3,T-bet,ACE,ACE2,Ang Ⅱ,AT1R,AT2R and the cytokine receptors IL-4,IL-5,IL-13 and IFN-γ in the lung tissue.Feces were collected for 16S rRNA gene high-throughput sequencing to analyze the composition and diversity of intestinal flora.Results Com-pared with the control group,the asthma group showed significant increases in the degree of airway inflammation;the ratio of Th1/2 elevated in the spleen;the mRNA expressions of IL-4,IL-5,IL-13,GATA3,ACE,Ang Ⅱ,AT1R and AT2R in lung tissue were significantly higher,but those of IFN-γ,T-bet and ACE2 were significantly lower in the asthma group than those in the control group,respectively.There were almost no differences in the levels of phylum,class,order,family,genus and species of gut microorganisms.Compared with the asthma group,both the antibiotic group and the LGG group were able to reduce airway inflammation and inhibit the ACE/Ang Ⅱ/AT1R axis,but the LGG group showed a better ef-fect and a higher degree of intestinal flora diversity.Conclusion Supplementation of LGG can maintain the balance of in-testinal microecology,and the metabolites it produces may circulate through the bloodstream and have a therapeutic effect on asthma by inhibiting the ACE/Ang Ⅱ/AT1R axis and inhibiting the release of Th2-associated cytokines.The exact mechanisms involved still need to be further verified.
AsthmaIntestinal floraLacticaseibacillus rhamnosusRenin-angiotensin system
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