Therapeutic Potential of Specific Lacticaseibacillus rhamnosus Strains for DNCB-Induced Atopic Dermatitis in Mice

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease linked to epidermal barrier dysfunction, Th2-skewed immune polarization, and disrupted gut microbiota homeostasis. While probiotic interventions show promise in managing AD, the mechanisms governing strain-specific efficacy-particularly systemic modulation via the "gut-skin axis"-remaining to be fully elucidated. Methods: This study systematically compared the oral therapeutic effects of three Lacticaseibacillus rhamnosus strains (MG-A047, MG-A054, and LGG) in a 2,4-dinitrochlorobenzene (DNCB)-induced AD mouse model. Results: By integrating behavioral, histopathological, and serological assessments with 16S rRNA-based gut microbiota profiling and in vitro functional assays, this study offers a multidimensional evaluation of the strain-specific advantages and potential therapeutic mechanisms of three L. rhamnosus strains. The results demonstrate that MG-A054 most effectively alleviated cutaneous inflammation and pruritus, significantly reduced serum IgE and IL-4 levels, and attenuated epidermal hyperplasia and inflammatory cell infiltration (including mast cells and eosinophils). Mechanistically, this strain may directly inhibit hyaluronidase activity and mast cell degranulation, and specifically remodel the gut microbiota structure, thereby promoting a shift toward a healthier functional profile. Conclusions: These findings suggest that the superior efficacy of MG-A054 may be achieved through coordinated modulation of the gut-skin axis and related pathways. This study offers new mechanistic clues for understanding the strain-specific actions of probiotics and lays a preclinical foundation for the further development of MG-A054 as a potential targeted microecological therapy for AD.