Lactobacillus reuteri CCFM1072 and CCFM1040 with the role of Treg cells regulation alleviate airway inflammation through modulating gut microbiota in allergic asthma mice

This study investigated the effects of Lactobacillus (L.) reuteri strains on airway inflammation, immune responses, and gut microbiota in a house dust mite (HDM)-induced allergic asthma murine model. The L. reuteri strains CCFM1072 and CCFM1040, which increased Treg populations in the spleen, lowered airway inflammation as compared to other strains, downregulated histamine, IL-17A, IL-5, and IL-13 levels in the lungs, and reduced Th2-related immunoglobulin concentrations in serum. Gut microbiota and metabolism analysis revealed that CCFM1072 maintained the diversity of the gut microbiota, promoted the growth of L. reuteri and Bacteroides thetaiotaomicron, and increased propionate levels, whereas CCFM1040 remodeled the structure of the gut microbiota, particularly promoting the growth of Bifidobacterium, and these promoted bacteria were linked to the improvement of airway inflammation. In summary, the two L. reuteri strains have effects on alleviating airway inflammation partly depending on modulating gut microbiota, albeit differently, and promoting Tregs proliferation.