Mutation Research 723 (2011) 177–181 Contents lists available at ScienceDirect Mutation Research/Genetic Toxicology and Environmental Mutagenesis journa l h omepage: www.elsevier.com/locate/gentox C om mun i ty a ddress: www.elsevier.com/locate/mutres DNA damage and nitric oxide production in mice following infection with L. chagasi Larissa Ragozo Cardoso de Oliveira a,∗ , Gláucia Aparecida Gomes Cezário a , Carlos Roberto Gonc ¸ alves de Lima a , Vanessa Cristina Nicolete a , Eliana Peresi a , Maria Tereza de Síbio b , Mariele Cristina Modolo Picka a , Sueli Aparecida Calvi a a Tropical Diseases Department, Faculdade de Medicina de Botucatu – UNESP, São Paulo State University, Brazil b Internal Medicine Department, Faculdade de Medicina de Botucatu – UNESP, São Paulo State University, Brazil a r t i c l e i n f o Article history: Received 4 February 2011 Received in revised form 13 April 2011 Accepted 28 April 2011 Available online 5 May 2011 Keywords: Leishmania chagasi DNA damage NO production a b s t r a c t Leishmania chagasi, which causes visceral leishmaniasis in South America, is an obligate intracellular protozoan. Production of nitric oxide by macrophages during the inflammatory response is one of the main microbicidal mechanisms against this parasite. The goal of this study was to evaluate whether L. chagasi infection causes DNA damage in peripheral blood and spleen cells of Balb/c mice and whether such damage may be related to NO production. Balb/c mice were either infected with L. chagasi or maintained as controls. The single-cell gel electrophoresis (comet) assay was used to measure DNA damage in peripheral blood and spleen cells, and the Griess reaction was used to measure NO production in the spleen. L. chagasi infection induced DNA damage in peripheral blood and spleen cells of infected mice. Macrophages from the control group, challenged with L. chagasi, showed significantly (p < 0.05) greater NO production, compared to non-challenged cells. Treatment of spleen cells with N G -monomethyl-l-arginine (LNMMA) caused a significant reduction of NO production and DNA damage (p < 0.05). Our results indicate that L. chagasi induces DNA damage in the peripheral blood and spleen cells and that NO not only causes killing of the parasite but also induces DNA damage in adjacent cells. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Visceral leishmaniasis is generally caused by Leishmania dono- vani and Leishmania infantum, in the Old World and Leishmania chagasi in the New World, including Brazil. Leishmaniasis is a widely distributed endemic zoonosis, found in 88 countries around the world, with a prevalence exceeding 12 million individuals [1]. Infection leads to a variety of outcomes, ranging from asymp- tomatic infection to active disease, which is characterized by fevers, cachexia, hepatosplenomegaly and suppressed immune response [2]. Infectious agents may be carcinogenic to humans; it is estimated that 8–17% of the global cancer burden is caused by infectious agents – mainly viruses, such as papillomavirus, hepatitis C, but also bacteria and parasites such as Mycobacterium, Helicobacter pylori, and Trypanossoma cruzi [3–6]. An association between leishmani- asis and cancer has been demonstrated, especially with respect ∗ Corresponding author at: Tropical Diseases Department, Botucatu Medical School – UNESP, São Paulo State University, Distrito de Rubião Junior CEP, 18618- 000, Botucatu, São Paulo, Brazil. Tel.: +55 14 3811 6372/6212. E-mail address: larissaragozo@yahoo.com.br (L.R.C. de Oliveira). to malignant lesions of the skin and mucous membranes and as a predisposing factor for cancer [6–9]. Control and protection against Leishmania infection are medi- ated by the Th1 type response, and IFN- secreted by Th1 cells is the most potent macrophage activating cytokine leading to host resis- tance to infection with Leishmania parasites [10]. The generation of nitric oxide through the up-regulation of inducible NO synthase by IFN- and TNF- is the critical macrophage effector mechanism involved in the control of parasite replication [5,6,11]. NO is synthe- sized when l-arginine is converted to citrulline by inducible nitric oxide synthase (iNOs) enzyme activity. N G -monomethl-l-arginine (l-NMMA) inhibits this conversion, increasing amastigote survival and replication in murine macrophages [12], lesion size, and par- asite load, and also inducing immediate reactivation of infection in resistant animals. The mechanism by which NO action destroys this parasite is not fully established [13,14], but it is believed to act with reactive oxygen intermediates to damage mitochondrial DNA, proteins, and lipids [15]. NO can also react with prosthetic Fe–S groups of sensitive enzymes, such as aconitase, and the mito- chondrial electron transport chain complexes I and II, resulting in formation of ferrous-nitrosyl and the deactivation/degradation of these enzymes. Control of Leishmania infection is dependent on NO production [10]. However, elevated iNOs expression in 1383-5718/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.mrgentox.2011.04.009