Probiotic lactic acid bacterial strains MG4693 and MG5474 alleviate atopic dermatitis by enhancing intestinal barrier integrity and modulating the immune system

Abstract

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by barrier dysfunction and a Type 2 T helper cell-dominant immune response. Probiotics have emerged as promising candidates for the management of AD by modulating intestinal and systemic immune responses.

Objective: This study aimed to investigate the effects of Lacticaseibacillus paracasei MG4693 and Lactococcus lactis MG5474 on 2,4-dinitrochlorobenzene-induced AD mice.

Design: AD was induced in Bagg Albino/c (BALB/c) mice by repeated topical 2,4-dinitrochlorobenzene applications, followed by the daily oral administration of MG4693 or MG5474 for 5 weeks. Skin lesions and scratching behavior in the dorsal and ear skin were evaluated. Epidermal thickness, immune cell infiltration, and levels of thymic stromal lymphopoietin (TSLP) and filaggrin were assessed by histology and immunohistochemistry. Flow cytometry was used to analyze T- and B-cell populations in lymph nodes. Intestinal barrier integrity was concurrently evaluated to investigate the involvement of the gut–skin axis.

Results: Both strains significantly alleviated AD symptoms, reducing epidermal hyperplasia, eosinophil and mast cell infiltration, and TSLP expression while restoring filaggrin. In addition, these strains modulated T- and B-cell populations in the lymph nodes, indicating an immunomodulatory effect.

Discussion: Amelioration of AD symptoms appears to be mediated by enhanced intestinal barrier integrity and attenuation of Type 2 T helper cell-mediated inflammatory responses.

Conclusion: MG4693 and MG5474 attenuated AD pathology by improving intestinal barrier function and modulating systemic immune responses. They demonstrated potential as probiotic candidates to manage AD by targeting the gut–skin axis.