Abstract
Atopic dermatitis (AD) is the most common chronic inflammatory skin disease and is driven by strong type 2 immune responses. Lactobacillus helveticus NS8 (NS8), a probiotic strain isolated from Mongolian koumiss, has anti-inflammatory activities. Here, we evaluated the therapeutic potential of NS8 on AD-like skin lesions by using SKH-1 hairless mice that underwent three cycles of epicutaneous sensitization (EC) with ovalbumin (OVA). NS8 (5 × 108 CFU/day) was orally administered to mice from 2 weeks before the first sensitization until the end of the study. NS8 attenuated the symptoms and pathological changes in the skin of AD mice. For example, NS8 reduced epidermal and dermal thickening and significantly restrained the infiltration of mast cells, eosinophils, and CD4+ T cells into the dermis. By analysing the Th1/Th2 cytokines produced in skin lesions, we found that NS8 significantly suppressed the expression of IL-4, IL-5, and IL-13 (P < 0.05), while it had no discernible effect on the expression of IFN-γ. Systemically, NS-8 reduced the total IgE and OVA-specific IgE levels in serum (P < 0.05). Our study demonstrates that oral administration of L. helveticus NS8 effectively alleviates AD severity in mice by suppressing the Th2 immune response. NS8 may be a promising candidate for prophylactic and therapeutic treatments of allergic diseases, such as AD.