Therapeutic Effects and Immunomodulation of Suanbo Mineral Water Therapy in a Murine Model of Atopic Dermatitis

BACKGROUND Balneotherapy is widely used as an alternative treatment modality for AD. Although the clinical benefit of some mineral waters has been established, their mechanisms of action in alleviating AD are only partly understood. OBJECTIVE The clinical modification and immunomodulatory or anti-inflammatory effects of mineral water from the Suanbo hot springs on the differentiation and cytokine production of Th1, Th2, and regulatory T cells (Treg) were investigated using spleen, skin tissue, and serum from NC/Nga mice. METHODS The therapeutic effects of bathing in mineral water in a Dermatophagoides farinae body extract ointment (Dfb ointment)-induced AD mouse model were assessed by measuring the modified Scoring atopic dermatitis (SCORAD) index scores, transepidermal water loss (TEWL), histological and immunohistochemical changes of the skin lesion, serum levels of interferon (IFN)-γ, interleukin (IL)-4, IL-5 and immunoglobulin E, mRNA expression of IFN-γ, IL-4 and IL-5 of dorsal skin, and helper T cell differentiation in the spleen. RESULTS Bathing in mineral water significantly reduced the modified SCORAD index scores, TEWL, epidermal hyperplasia, and inflammatory cell infiltration. IL-4 production and Th2 cell differentiation showed a decreasing tendency with mineral water bathing, but the Th1 cells did not. On the contrary, differentiation to Treg cells was promoted with mineral water bathing. CONCLUSION Balneotherapy not only has anti-inflammatory activity, but also shows positive effects on cutaneous barrier homeostasis. These results suggest that the favorable effects of balneotherapy may be mediated by modifying the Th2 response, and possibly in part by inducing Treg cell differentiation.