Qing-Re-Chu-shi decoction ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice through anti-inflammation and immunoregulatory mechanisms

Qing-Re-Chu-Shi Decoction (QRCSD), a traditional Chinese herbal formula, has been employed as a complementary and alternative therapy for inflammatory skin diseases. However, its active constituents and the mechanistic basis of its action on atopic dermatitis remain in adequately understood. Atopic dermatitis (AD) is an allergic dermatitis marked by eczematous lesions and pruritus. The study aimed to elucidate the underlying effects of QRCSD on AD and to identify the components responsible for its therapeutic efficacy in a mouse model. Network pharmacology and UPLC-mass analysis were used to anticipate the pharmacological mechanisms and to identify active components of QRCSD, respectively. A DNCB-induced AD-like model was established in NC/Nga mice. QRCSD or prednisolone (as a positive control) was administered via gavage every other day from day14 to day 21. Dermatitis severity score, scratching behavior, skin barrier function, spleen index, Th1/Th2 lymphocyte ratio, and serum IgE levels were evaluated. Protein arrays, including 40 inflammatory cytokines, were performed on skin lesions, followed by confirmation experiments of Western blotting in dorsal skin lesions. The construction of a QRCSD-AD-Network and topological analysis firstly proposed potential targets of QRCSD acting on AD. Animal experiments demonstrated that oral administration of QRCSD ameliorated AD-like lesions, reduced epidermal thickness and mast cell count, decreased serum IgE levels, augmented tight junction protein (Claudin 1, Occludin) levels, and regulated the Th1/Th2 balance in the spleen, as well as spleen index. Elevated levels of interleukin (IL)-4, IL-5, IL-6, IL-17, and Eotaxin were revealed in AD-like skin lesions by protein arrays. Western blotting confirmed that the phosphorylation levels of ERK, P38, JNK, STAT3 and P65 were downregulated, and IL-6 expression was also reduced following QRCSD treatment. The study enhances the understanding of the anti-inflammatory and immunomodulatory effects of QRCSD, showcasing its significant protective role against atopic dermatitis. Treatment with QRCSD may be considered as a viable candidate for complementary and alternative therapy in managing atopic dermatitis.