In vitro and in vivo estrogenic activity of triclosan

ABSTRACT

Triclosan (TCS) is an antibacterial and antifungal agent used in many consumer products and exhibits a chemical structure similar to non-steroidal estrogen, which is known to induce endocrine disruption. Triclosan has been found in human plasma, urine, and breast milk, and the safety of TCS-containing products has been disputed. Although studies attempted to determine the estrogenic activity of TCS, no clear results have emerged. The aim of the present study was to examine estrogenic activity of TCS using an in vitro E-screen assay and an in vivo uterotrophic assay. The in vitro E-screen assay demonstrated that TCS significantly enhanced proliferation of MCF-7 breast cancer cells, although not in a concentration-dependent manner. The in vivo uterotrophic results showed no significant change in the weight of uteri obtained from TCS-administered Sprague-Dawley rats. Further, to understand the estrogenic activity attributed to TCS at the molecular level, gene-expression profiling of uterus samples was performed from both TCS- or estrogen-treated rats and the genes and cellular processes affected by TCS or estrogen were compared. Data demonstrated that both the genes and cellular processes affected by TCS or estrogen were significantly similar, indicating the possibility that TCS-mediated estrogenic activity occurred at the global transcriptome level. In conclusion, in vitro and gene-profiling results suggested that TCS exhibited estrogenic activity.

KEYWORDS:

• Triclosan
• Estrogenic activity
• Uterotrophic assay
• E-screen assay
• DNA microarray

Abbreviations

DAVID: Database for Annotation, Visualization and Integrated Discovery; DEG: differentially expressed gene; DES: diethylstilbestrol; DMEM: Dulbecco’s modified Eagle medium; DMSO: dimethyl sulfoxide; E2: 17β-estradiol; EDC: endocrine-disrupting chemical; EE: ethinyl estradiol; EPA: Environmental Protection Agency; FBS: fetal bovine serum; GOBP: Gene Ontology biological process; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; OECD: Organization for Economic Cooperation and Development; SD: Sprague–Dawley; TCS: triclosan

Acknowledgments

This Research was financially supported by Changwon National University during 2021∼2022.

Disclosure statement

The authors declare that they have no conflicts of interest.