NaHCO3- and NaCl-Type Hot Springs Enhance the Secretion of Inflammatory Cytokine Induced by Polyinosinic-Polycytidylic Acid in HaCaT Cells

Abstract

Background: Hot springs have been traditionally used as an alternative treatment for a wide range of diseases, including rheumatoid arthritis, bronchial asthma, diabetes, hypertension, psoriasis and atopic dermatitis. However, the clinical effects and therapeutic mechanisms associated with hot springs remain poorly defined. Objective: The purpose of this study was to demonstrate the different effects of hot springs on cellular viability and secretion of inflammatory cytokines on keratinocyte in two geographically representative types of hot springs: NaHCO3-type and NaCl-type, which are the most common types in South Korea. Methods: We performed WST-1, BrdU measurements, human inflammatory cytokine arrays and enzyme-linked immunosorbent assay in HaCaT cells stimulated with toll-like receptor 3 by polyinosinic-polycytidylic acid. Results: The interaction effects of cell viability and cell proliferation were not significantly different regardless of polyinosinic-polycytidylic acid stimulation and cultured hot springs type. Cytokine array and enzyme-linked immunosorbent assay analysis showed increased expression of inflammatory cytokines such as interleukin-6 and granulocyte-macrophage colony-stimulating factor by polyinosinic-polycytidylic acid stimulation, with expression levels differing according to hot springs hydrochemical composition. Cytokine reduction was not significant. Conclusion: The effects and mechanisms of hot springs treatment in keratinocytes were partially elucidated.