Host: The Japanese Society of Toxicology
Name : The 49th Annual Meeting of the Japanese Society of Toxicology
Date : June 30, 2022 - July 02, 2022
Keratinocytes play an important role in the epidermal defense barrier and have been reported to release cytokines and other substances in response to external stimuli and to induce the activation of immune cells. Some of the bioactive substances released are classified as itch mediators, which are involved in the induction of itch, but the details are unknown. Itch mediators have been reported to induce allergy, and scratching to itch may lead to inflammation. In this study, we focused on metal compounds contained in cosmetics and analyzed the effects of metal compounds on the production of itch mediators by keratinocytes, because itching may occur when cosmetics are applied directly to the skin.
Administration of phorbol 12-myristate13-acetate (PMA) at 100 µmol/L, histamine at 300 µmol/L and lipopolysaccharide (LPS) at 2 mg/mL increased the mRNA expression levels of IL-31 and IL-33, but did not affect mRNA level of thymic stromal lymphopoietin, Cathepsin S, or Endothelin-1. Administration of metal compounds showed no change in all itch mediators. There was a tendency for histamine and PMA administration to enhance the increased expression of IL-31 and IL-33 under metal compound treatment. These results suggested that the metal compound did not directly cause itching, but modulated the responsiveness of keratinocytes. Furthermore, by measuring the IL-31 and IL-33 mRNA expression levels of keratinocytes under various conditions, it was considered that the possibility of leading to itching could be evaluated.
