Sperm motility and morphology changes in rats exposed to cadmium and diazinon

Adamkovicova et al. Reproductive Biology and Endocrinology (2016) 14:42 DOI 10.1186/s12958-016-0177-6 RESEARCH Open Access Sperm motility and morphology changes in rats exposed to cadmium and diazinon Maria Adamkovicova1, Robert Toman2, Monika Martiniakova3, Radoslav Omelka1, Ramona Babosova3, Vladimira Krajcovicova1, Birgit Grosskopf4* and Peter Massanyi5 Abstract Background: Humans are ubiquitously exposed to multiple environmental contaminants. Consequences of combined action on the reproductive system remain unknown. This study aimed to assess single and joint effects of cadmium and diazinon exposure on sperm quality parameters. Methods: Male adult Wistar rats were randomized into 4 groups of ten animals each. Group A was used as a control, animals from group B were exposed to cadmium (30 mg/L), rats from group C were administered with diazinon (40 mg/L), and rats from group D were exposed simultaneously to cadmium (30 mg/L) and diazinon (40 mg/L) via drinking water for 90 days. Sperm morphology and motility were evaluated using a bright field microscope and a computer-assisted semen analysis. Results: The percentage of motile spermatozoa and morphologically normal sperm was markedly reduced in rats from the group B. Rats from the C group showed an increase in velocity parameters, amplitude of lateral head displacement, decrease in beat-cross frequency, and an increase in abnormal sperm morphology. Simultaneous coexposure to cadmium and diazinon increased distance and velocity parameters, and amplitude of lateral head displacement. Reductions were observed in straightness, linearity, wobble, and beat-cross frequency. The decreased normal sperm morphology rates were related to defects of the sperm tail. Conclusions: Exposure to cadmium and diazinon at relatively low doses impairs sperm quality and can reduce male fertility. Cadmium and diazinon caused significant changes on sperm morphology with varying effects on motility patterns. These parameters were significantly higher in the group D as compared to the group C. The findings have important implications for reproductive risk assessment of combined exposures to multiple chemicals. Keywords: Sperm, Motility, Morphology, Rat, Cadmium, Diazinon Background Cadmium (Cd) is a globally widespread toxic element which has no known biological function. Environmental pollution with Cd can produce a wide range of adverse health effects in both experimental animals and humans [1]. Apart from occupational exposure, food is the main source of Cd for the non-smoking population. The accumulation of Cd over time can severely damage the lungs, liver, kidney, bone, and reproductive system [2, 3]. Male reproductive toxicity induced by Cd involves various mechanisms such as direct effect on the testicular tissue, * Correspondence: 4 Institute of Zoology and Anthropology, Georg-August University, 37 073 Göttingen, Germany Full list of author information is available at the end of the article altered accessory sex gland secretions, resulting in decreased semen quality and indirect endocrine effects, causing suppression of steroid biosynthesis [4, 5]. Cd affects multiple cellular processes, including cell proliferation, differentiation, and apoptosis [6]. In the testis, disruption of intracellular junctions due to Cd toxicity on vascular system results in hemorrhage, edema, necrosis and germ cells damage [7, 8]. Another factor that may cause disruption of spermatogenesis in the testes is oxidative stress. The excessive production of reactive oxygen species (ROS) leads to decline observed in normal morphology, concentration, and motility of sperms [9, 10]. Diazinon (DZN) is an organophosphorus synthetic insecticide entering the environment from agricultural and household application of the chemical to control pest © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Adamkovicova et al. Reproductive Biology and Endocrinology (2016) 14:42 insects [11]. For the general population, dietary exposure to DZN residues, particularly in vegetables and fruits, is the most likely route of exposure. Following absorption into the body, DZN is bioactivated through desulfuration to oxygen analogues diazoxon, which is more toxic than the parent compound [12, 13]. The primary effects of DZN are mediated through an inhibition of acetylcholinesterase in the peripheral and central nervous systems [14]. DZN is one of the most important insecticides that are associated with decreased semen quality in men [15]. Organophosphate insectides alter male reproductive function inducing spermatogenic disturbances through hormonal or genotoxic mechanisms [16]. Furthermore, the induction of oxidative stress associated with defective sperm function and reduced male fertility has been observed after DZN exposure [17, 18]. Prolonged exposure to DZN alters semen quality and sperm chromatin, reduces sperm motility and viability, and increase sperm morphological abnormalities [19, 20]. Humans can be exposed simultaneously or sequentially to complex mixtures of environmental chemicals from numerous sources. Attention has recently been focused on adverse reproductive outcomes associated with widespread and permanent contamination by heavy metals and pesticides [21, 22]. However, the effects of potential interactions between different chemicals on the reproductive toxicity remain unknown [23]. Sperm motility and morphology parameters are very important semen characteristics [24]. Therefore, the present study was designed to determine the single and combined effects of Cd and DZN on sperm parameters in rats in relation to evaluate their potential interaction. Methods Chemicals Cd in the form of cadmium chloride (CdCl2), with purity 96 %, was purchased from Reachem, Slovak Republic. Pestanal grade DZN, analytical standard (C12H21N2O3PS), with purity 99 %, was obtained from Sigma-Aldrich Laborchemikalien GmbH, Germany. Animals The experiments were performed using male Wistar rats obtained from the accredited breeding and experimental laboratory (SK PC 50004, SUA Nitra). The rats were individually housed in plastic cages in an environment maintained at 20–24 °C, 55 ± 10 % humidity and 12/ 12 h cycle of light and darkness with access to food (feed mixture M3, Machal, Czech Republic) and drinking water ad libitum. Experimental design In a 90-day study of oral toxicity, the 4 week old Wistar rats were randomly assigned into fo (...truncated)