Contents lists available at ScienceDirect Journal of Trace Elements in Medicine and Biology journal homepage: www.elsevier.com/locate/jtemb Effects of furosemide administration on the concentration of essential and toxic elements in Wistar rats by inductively coupled plasma optical emission spectrometry Luiz Raimundo Seneterri Silva Rodrigues dos Santos a , Aníbal de Freitas Santos Júnior b, ⁎ , Maria das Graças Andrade Korn a a Chemistry Institute, Universidade Federal da Bahia, 40170-115 BA Salvador, Brazil b Department of Life Sciences, Universidade do Estado da Bahia, 41195-001 BA Salvador, Brazil ARTICLE INFO Keywords: Biological samples Trace elements Wistar rats Furosemide ICP OES ABSTRACT Furosemide can interfere with the metabolism of chemical elements, changing their levels in several tissues, thus causing imbalance. In this study, inductively coupled plasma optical emission spectrometry (ICP OES) was used for multi-element analysis (Cd, Cu, Fe, Mg, Pb, Se and Zn) after microwave-assisted digestion, to evaluate the effect of furosemide (loop diuretic) on the composition of these essential and toxic elements in biological samples (liver, kidney, heart, lung and serum) of Wistar rats. Male and female Wistar rats (n = 40, 180–350 g) were randomly divided into 2 groups (n = 20/group). The results were expressed as μg/g dry weight. The mean tissue concentrations (minimum-maximum in μg/g) of Cu, Fe, Mg and Zn in the biological samples ranged between 5.2 and 1023.5. The levels of Cd, Pb and Se were below the detection limit of the ICP OES. Accuracy was assessed by microwave-assisted digestion and recovery values of 83–116% were obtained. Liver had significantly higher trace element concentrations in most of the analyzed samples. Mg showed a significant reduction (for males and females) in its levels in the heart. In both genders, there was similarity in the Cu concentration reduction (around 16%) for all tissues. The highest iron losses were found for serum (52% and 12%) for male and female rats, respectively. Reductions in Zn occurred between 0.3 and 18.0%, mainly for kidneys and heart, respectively. This study demonstrated that furosemide altered the concentration of some elements in rats. 1. Introduction Monitoring essential and toxic elements in biological samples is extremely important, since variations in concentration can cause dis- eases and metabolic disorders [1–5]. The obtention of values related to elemental concentrations in organs and tissues of different species is necessary as a source of reference data for nutritional, environmental, pharmacological, toxicological and other evaluations in animals and humans [6–12]. However, the number of elements determined in spe- cific organs of animals has been limited in previous studies, especially those using small rodents. The use of diuretics may alter levels of essential elements and, consequently, lead to disorders [13]. Some drugs can interfere with the metabolism of chemical elements, changing their levels, thus causing imbalance [14–17]. Furosemide is a loop diuretic, widely used in clinical practice to treat cardiovascular diseases, which causes the elimination of many elements from the body [18]. In addition, the elimination of other essential elements from the organism can cause disturbances, which requires the evaluation of the availability of these metals in organisms that use furosemide in the long term [19]. How- ever, the current literature does not provide much information on the physiological and qualitative changes of essential elements and con- taminants in the composition of animal tissues. Analytical determinations from biological tissue samples require sample digestion [20–22] and sensitive techniques, with lower limits of detection, higher analytical speed, low cost and relative lack of analy- tical interference. The microwave acid digestion method is a fast and reproducible extraction procedure for samples of biological importance, such as tissues and human blood [6,23]. Inductively coupled plasma optical emission spectrometry (ICP OES) has the advantages described above, in addition to good quantitative multi-element capability, wide linear dynamic ranges and reasonable cost [24–26]. The aim of this study was to evaluate the effect of furosemide on the composition of Cd, Cu, Fe, Mg, Pb, Se and Zn in biological samples (liver, kidney, lung and serum) of Wistar rats, by axial view ICP OES, after microwave-assisted digestion. https://doi.org/10.1016/j.jtemb.2018.02.029 Received 29 December 2017; Received in revised form 30 January 2018; Accepted 27 February 2018 ⁎ Corresponding author. E-mail address: afjunior@uneb.br (A. de Freitas Santos). Journal of Trace Elements in Medicine and Biology 48 (2018) 25–29 0946-672X/ © 2018 Elsevier GmbH. All rights reserved. T