Mutation Research 676 (2009) 83–86 Contents lists available at ScienceDirect Mutation Research/Genetic Toxicology and Environmental Mutagenesis journal homepage: www.elsevier.com/locate/gentox Community address: www.elsevier.com/locate/mutres The azo dyes Disperse Red 1 and Disperse Orange 1 increase the micronuclei frequencies in human lymphocytes and in HepG2 cells Farah Maria Drumond Chequer a,∗ , José Pedro Friedmann Angeli b , Elisa Raquel Anastácio Ferraz a , Marcela Stefanini Tsuboy b , Juliana Cristina Marcarini b , Mário Sérgio Mantovani b , Danielle Palma de Oliveira a a USP, Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, 14040-903, SP, Brazil b UEL, Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Campus Universitário, Londrina, 86061-990, PR, Brazil article info Article history: Received 17 November 2008 Received in revised form 3 April 2009 Accepted 6 April 2009 Available online 14 April 2009 Keywords: Disperse Red 1 Disperse Orange 1 Micronucleus HepG2 cells Lymphocytes abstract The use of azo dyes by different industries can cause direct and/or indirect effects on human and envi- ronmental health due to the discharge of industrial effluents that contain these toxic compounds. Several studies have demonstrated the genotoxic effects of various azo dyes, but information on the DNA damage caused by Disperse Red 1 and Disperse Orange 1 is unavailable, although these dyes are used in dyeing processes in many countries. The aim of the present study was to evaluate the mutagenic activity of Dis- perse Red 1 and Disperse Orange 1 using the micronucleus (MN) assay in human lymphocytes and in HepG2 cells. In the lymphocyte assay, it was found that the number of MN induced by the lowest concen- tration of each dye (0.2 g/mL) was similar to that of the negative control. At the other concentrations, a dose response MN formation was observed up to 1.0 g/mL. At higher dose levels, the number of MN decreased. For the HepG2 cells the results were similar. With both dyes a dose dependent increase in the frequency of MN was detected. However for the HepG2, the threshold for this increase was 2.0 g/mL, while at higher doses a reduction in the MN number was observed. The proliferation index was also calculated in order to evaluate acute toxicity during the test. No differences were detected between the different concentrations tested and the negative control. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Synthetic dyes are extensively used in the textile dyeing, paper printing, photography, pharmaceutical, food, cosmetics and petroleum products industries [1,2]. More than 800,000 tons of dyes are annually produced worldwide and 60–70% of them belong to the azo group [3,4]. The acute toxicity of azo compounds is generally low [5], but some dyes have been linked with the induction of bladder cancer in humans, and of splenic sarcomas, hepatocarcinomas and nuclear anomalies in experimental animals [6,7]. In addition a number of studies have indicated that some of these compounds are able to cause DNA damage. It is known that the mutagenic activity of the azo dyes depends strongly on their chemical structure [8–11], and therefore the mutagenic responses for these compounds cannot be generalized for the whole group and each dye should be studied ∗ Corresponding author. Tel.: +55 16 3602 0663. E-mail address: fchequer@fcfrp.usp.br (F.M.D. Chequer). individually. Azo dyes are frequently used for coloring purposes in many countries [12], including Disperse Red 1 and Disperse Orange 1(Fig. 1). However, no information on the mutagenicity of these dyes is available in the literature. The MN assay is one of the most widely used methods for assess- ing chromosomal damage, since it detects both chromosomal loss and chromosomal breakage [13,14]. Chromosomal loss and malseg- regation (non-disjunction) show key roles in the appearance of cancer and in ageing. They are probably caused by defects in the spindle or centromere, or as a consequence of under-condensation of the chromosomal structure before the metaphase [15]. Therefore the MN assay with human cells has become one of the standard cytogenetic tests for genetic toxicology testing. Using Cytochalasin B in the cytokinesis-block micronucleus (CBMN) assay, it is possible to score MN in binucleated cells (BN) [13,16]. Different cell lines can be used in mutagenicity studies with the MN assay, including lymphocytes and HepG2. The determination of the MN frequency in peripheral lymphocytes has been considered as a candidate cancer risk biomarker [17–19], clearly demonstrating the relevance of using this system in mutagenic studies. On the other hand, HepG2 cells are useful tools to express the activities of 1383-5718/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.mrgentox.2009.04.004