title: Triclosan, an antibacterial agent, increases intracellular Zn(2+) concentration in rat thymocytes: its relation to oxidative stress.
abstract: Triclosan is used as an antibacterial agent in household items and personal care products. Since this compound is found in maternal milk of humans and bodies of wild animals, there is growing concern among some consumer groups and scientific community that triclosan is adverse for humans and wild animals. In order to estimate adverse actions of triclosan, the effects of triclosan on intracellular Zn(2+) concentration and cellular thiol content were studied in rat thymocytes by the use of flow cytometer with appropriate fluorescent probes. Triclosan at 1-3 μM (sublethal concentrations) increased the intensity of FluoZin-3 fluorescence (intracellular Zn(2+) concentration) and decreased the intensity of 5-chloromethylfluorescein (5-CMF) fluorescence (cellular thiol content). Negative correlation (r=-0.985) between triclosan-induced changes in FluoZin-3 and 5-CMF fluorescences was found. Removal of external Zn(2+) did not significantly affect the triclosan-induced augmentation of FluoZin-3 fluorescence, suggesting an intracellular Zn(2+) release by triclosan. These actions of triclosan were similar to those of H(2)O(2) and triclosan significantly potentiated the cytotoxicity of H(2)O(2). Therefore, the results may suggest that triclosan at sublethal concentrations induces oxidative stress that decreases cellular thiol content, resulting in an increase in intracellular Zn(2+) concentration by Zn(2+) release from intracellular store(s). Since recent studies show many physiological roles of intracellular Zn(2+) in cellular functions, the triclosan-induced disturbance of cellular Zn(2+) homeostasis may induce adverse actions on the cells.
authors: Division of Environmental Symbiosis Studies, Graduate School of Integrated Arts and Sciences, The University of Tokushima, Tokushima 770-8502, Japan.
authors: Ikumi
authors: I
authors: Tamura
authors: Yasuhiro
authors: Y
authors: Kanbara
authors: Minoru
authors: M
authors: Saito
authors: Kanna
authors: K
authors: Horimoto
authors: Masaya
authors: M
authors: Satoh
authors: Hiroshi
authors: H
authors: Yamamoto
authors: Yasuo
authors: Y
authors: Oyama
mesh_terms: D000818:Animals; D004785:Environmental Pollutants / Q000008:administration & dosage / Q000633:toxicity*; D005434:Flow Cytometry / Q000662:veterinary; D005452:Fluoresceins; D005456:Fluorescent Dyes / Q000737:chemistry; D006706:Homeostasis; D018384:Oxidative Stress; D011083:Polycyclic Compounds; D011419:Propidium; D051381:Rats; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D060168:Thymocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D014260:Triclosan / Q000008:administration & dosage / Q000633:toxicity*; D015032:Zinc / Q000378:metabolism*
chemical_list: D004785:Environmental Pollutants; C451182:FluoZin-3; D005452:Fluoresceins; D005456:Fluorescent Dyes; D011083:Polycyclic Compounds; D013438:Sulfhydryl Compounds; C069306:5-chloromethylfluorescein; D011419:Propidium; D014260:Triclosan; D015032:Zinc