Paeonia lactiflora Pallas extract alleviates antibiotics and DNCB-induced atopic dermatitis symptoms by suppressing inflammation and changing the gut microbiota composition in mice

Atopic dermatitis (AD) is a highly prevalent inflammatory skin disease worldwide. Recent studies have suggested an important role for association with the gut and skin microbiome axis in AD development. Paeonia lactiflora Pallas extract (PL) is commonly used for the treatment of inflammatory diseases. However, the possible mechanisms by which PL can alleviate AD by regulating the gut microbiota have not been investigated. In this study, we aimed to investigate the therapeutic effects and underlying mechanism of PL in mice with antibiotic cocktail (ABX)-induced AD. The effects of PL were evaluated in bone marrow-derived macrophages (BMDMs) and ABX and dinitrochlorobenzene (DNCB) mouse models. PL suppressed inflammatory cytokine and NO production in LPS-treated BMDMs. Moreover, PL attenuated scoring atopic dermatitis (SCORAD) scores, epidermal thickness, white blood cell counts and the disease activity index (DAI) in ABX-induced AD mice. Meanwhile, PL decreased IL-17A production, induced Foxp3 expression and improved intestinal barrier integrity by especially increasing the expression of tight junction proteins such as ZO-1 and occludin. Additionally, PL partially increased the diversity of the gut microbiota and changed the microbial composition. Our findings suggest that PL may be a potential natural product that can ameliorate atopic dermatitis symptoms by suppressing inflammatory cytokine production, inducing Foxp3 expression, increasing intestinal barrier integrity and changing the gut microbiota composition.