Immunomodulatory Effects of Balneotherapy with Hae-Un-Dae Thermal Water on Imiquimod-Induced Psoriasis-Like Murine Model

BACKGROUND Balneotherapy, although not a well-established dermatological treatment, is thought to have therapeutic properties for psoriasis and is used as an alternative treatment modality throughout the world. OBJECTIVE To evaluate the mechanism underlying the therapeutic immunologic effects of thermomineral water. METHODS A murine model of imiquimod-induced psoriasis-like skin inflammation was used for evaluating the therapeutic effects of balneotherapy with Hae-Un-Dae hot spring mineral water. The clinical improvements were evaluated by a dermatologist. Lesional cytokines, including interleukin (IL)-17A, IL-23, and IL-22, were quantitatively measured by real-time reverse transcriptase polymerase chain reaction. Serum levels of interferon-γ, IL-4, IL-5, and IL-17A were measured by enzyme-linked immunosorbent assay. T cell proportions in the spleen were evaluated by flow cytometry, and histopathological evaluation of the skin was also performed. RESULTS The mineral water balneotherapy group showed faster improvement in skin erythema and scales than the distilled water bathing group. A substantial reduction was observed in the lesional mRNA levels of IL-17A and IL-23 in the mineral water group. Serum levels of IL-4 and IL-5 were significantly decreased in the mineral water group but not in the distilled water group. Normalized T cell proportions were observed after bathing. CONCLUSION Balneotherapy showed immunomodulatory effects in a psoriasis-like murine model. Balneotherapy suppressed lesional IL-23 and IL-17A, which are important cytokines in the pathogenesis of psoriasis. These results suggest that balneotherapy can be used as an effective and safe treatment for psoriasis.