%0 Journal Article
%T Effects of Hydroquinone on Cytoskeletal Organization and Intracellular Transport in Cultured Xenopus laevis Melanophores and Fibroblasts
%A Sara Aspengren
%A Elisabeth Norstr£¿m
%A Margareta Wallin
%J ISRN Cell Biology
%D 2012
%R 10.5402/2012/524781
%X Hydroquinone is used as a skin-lightening agent, it is also present in different chemical products and cigarette smoke. It is believed to inhibit melanin production in melanocytes by inhibiting the key enzyme tyrosinase. In the present study, we show that hydroquinone had severe effects on microtubules and actin filaments in cultured Xenopus laevis melanophores as studied by immunohistochemistry. It affected the intracellular transport of melanosomes, induced bundling of microtubules and disassembly of actin filaments at 10 and 50£¿¦̀M, and at 100£¿¦̀M proper adhesion to the substrate was lost. Effects occurred at lower concentrations than what previously has been stated to be cytotoxic, and the results show that tyrosinase is not the only cellular target. The cytoskeleton is of utmost importance for the function of all cells and across species. Our data has therefore to be considered in the discussions about the use of hydroquinone for bleaching of skin. 1. Introduction Hydroquinone (HQ) is a synthetically produced and naturally occurring chemical that is used for example in cosmetics as a skin-lightening agent, as a reagent in photographic developers, and in rubber manufacture [1]. It is also present in significant levels in cigarette smoke [2]. Genomic and proteomic analyses have shown that HQ treatment induces changes in proteins that are involved in for instance oxidative stress, focal adhesion, cellular signalling, and cytoskeleton reconstruction [1¨C3]. As a skin-lightening agent, HQ is believed to act by inhibition of the enzyme tyrosinase, thereby reducing the conversion of dihydroxybenzoic acid (DOPA) to melanin [4, 5]. Administration of HQ induces reduced pigmentation in mammals [6] and has been suggested to have a selective melanotoxic action. Using melanocytes and nonmelanotic cells, it has been demonstrated that sensitivity to the cytotoxic effects of HQ is associated with the presence of tyrosinase activity [7], and cytotoxicity is increased when cells are exposed to UVA radiation [8]. Uncontrolled use of HQ-containing bleaching products has resulted in an epidemic of postinflammatory hyperpigmentation (exogenous ochronosis) in South Africa [9, 10]. Due to the toxicological side effects the use of HQ in cosmetics has been banned in the European Union [11], but it is still allowed in many countries. In order to gain further insight in potential mechanism(s) of action and cellular effects of HQ, we have used immortalized melanophores from the African clawed frog, Xenopus laevis. Melanophores derive from the neural crest and are cells specialized
%U http://www.hindawi.com/journals/isrn.cell.biology/2012/524781/