Triclosan exacerbates atopic dermatitis in mouse models via thymic stromal lymphopoietin.

Abstract

Background: Triclosan, a common antimicrobial agent, is widely used in personal-care products and as a topical antiseptic in atopic dermatitis (AD).

Objective: This study aimed to evaluate the topical and systemic effect of triclosan on AD in murine models, with a specific focus on the role of thymic stromal lymphopoietin (TSLP).

Methods: AD-like skin disease was induced by topical application of MC903 and house dust mites in female wildtype BALB/c, C57BL/6 J, and TSLP receptor (TSLPR)-knockout mouse strains. Mice were treated with triclosan both topically and systemically. Skin inflammation was assessed by measuring ear thickness. Infiltration of immune cells was analyzed by flow cytometry and immunohistochemistry (IHC). Cytokine expression was determined by quantitative real-time PCR.

Results: Triclosan application induced skin inflammation in a dose-dependent manner. Topical triclosan treatment increased ear inflammation and immune cell infiltration in AD-like mouse models. Systemic administration of triclosan also enhanced local AD-like skin reactions. Triclosan-induced skin inflammation was reduced in TSLP-receptor-knockout mice or by blocking TSLP, thus indicating the pivotal role of TSLP in mediating the immunological effects of triclosan.

Conclusions: Topical and systemic administration of triclosan exacerbates AD-like skin inflammation in murine models, with TSLP being a central mediator of this process. The translational relevance of these findings to human disease remains uncertain, as no direct human data are available.