Gut microbiota of mice treated with LF216EV

Atopic dermatitis (AD) is a prevalent, chronic inflammatory skin disorder with complex pathogenesis, presenting significant therapeutic challenges. This study investigates the effects of probiotic-derived extracellular vesicles on AD. We administered Limosilactobacillus fermentum SLAM 216 derived extracellular vesicles (LF216EV) orally to BALB/c mice with AD induced by 2,4-dinitrochlorobenzene (DNCB). LF216EV alleviated AD-like symptoms, including redness, scaling, and excoriation, and decreased epidermal thickness and mast cell infiltration. Additionally, LF216EV reduced scratching and depression-related behaviors more rapidly than Dexamethasone. qRT-PCR analysis revealed increased expression of serotonin-associated genes (htrb2c, sert, tph-1) in the skin and gut, along with elevated serum serotonin levels. Gut microbiome analysis indicated that LF216EV adjusted gut microbiota profiles, with Limosilactobacillus and Desulfovibrio linked to changes in intestinal metabolites, including serotonin. These findings suggest that LF216EV mitigates AD symptoms by enhancing serotonin synthesis through gut microbiota modulation.