Anti-muscle Atrophy Effects ofLactobacillus reuteriATG-F4 and Its Impact on Intestinal Microbiota and Metabolites: Implications for Prophylaxis and Therapy

Lactobacillus reuteri ATG-F4, human gut-derived bacteria, was orally administrated in a model of hindlimb immobilization and confirmed the muscular performance, muscle mass and mechanism on anti-atrophy study. Concomitantly, the changes in the intestinal flora, the metabolites and cytokines were investigated. In the stapled immobilization mice model, ATG- F4 treated group had significantly increased muscle mass, myofiber size, running time to be exhausted and grip strength. The cytokine levels in serum and muscle tissues were reduced by ATG-F4 treatment. Furthermore, the phosphorylation of proteins involved in muscle synthesis such as mTOR, p70S6K, rpS6 and 4E-BP1 increased and MuRF1 related to muscle atrophy factor reduced in the TA and GA muscles. ATG-F4 treatment changed the ratio of main intestinal microflora by increasing the family Muribaculaceae ( phylum Bacteroidetes ) and decreasing the family Lachnospiraceae ( phylum Firmicutes ) and Lactobacillaceae ( phylum Firmicutes ). Also, the level of short chain fatty acids (SCFAs) including butyric acid and acetic acid in the serum of ATG-F4 group were increased. These results suggest that L. reuteri ATG- F4 can inhibit muscle atrophy and it is associated with the microbiota and its metabolites with the anti-inflammation effect. ATG-F4 may be a potential prophylactic or therapeutic composition for muscle atrophy.