Preventive and Therapeutic Effects of Lactiplantibacillus plantarum HD02 and MD159 through Mast Cell Degranulation Inhibition in Mouse Models of Atopic Dermatitis

As the relationship between the gut microbiome and allergies becomes better understood, targeted strategies to prevent and treat allergies through gut microbiome modulation are being increasingly developed. In the study presented herein, we screened various probiotics for their ability to inhibit mast cell degranulation and identified <i>Lactiplatibacillus plantarum</i> HD02 and MD159 as effective candidates. The two strains significantly attenuated vascular permeability induced by mast cell degranulation in a passive cutaneous anaphylaxis (PCA) model and, in the MC903-induced murine atopic dermatitis (AD) model, demonstrated comparable preventive effects against allergies, reducing blood levels of MCPT-1 (mast cell protease-1) and total IgE. In the house dust mite (HDM)-induced murine AD model, both <i>L. plantarum</i> HD02 and MD159 showed therapeutic effects, with <i>L. plantarum</i> HD02 demonstrating superior efficacy. Nevertheless, <i>L. plantarum</i> MD159 better suppressed transepidermal water loss (TEWL). Furthermore, <i>L. plantarum</i> HD02 and MD159 significantly increased the number of splenic Foxp3⁺ regulatory T cells, with <i>L. plantarum</i> MD159 having a more pronounced effect. However, only <i>L. plantarum</i> HD02 achieved a reduction in immune cells in the draining lymph nodes. Our findings highlight <i>L. plantarum</i> HD02 and MD159 as promising candidates for the prevention and treatment of allergies, demonstrating significant efficacy in suppressing mast cell degranulation, reducing the number of allergy biomarkers, and modulating immune responses in experimental models of AD. Their distinct mechanisms of action suggest potential complementary roles in addressing allergic diseases, underscoring their therapeutic promise in clinical applications.