CADMIUM AND DIAZINON-INDUCED CHANGES IN THE RAT TESTIS STRUCTURE AFTER A PERORAL ADMINISTRATION IN DRIKING WATER

Journal of Microbiology, Biotechnology and Food Sciences Toman et al. 2012 : 2 (2) 564-575 REGULAR ARTICLE CADMIUM AND DIAZINON-INDUCED CHANGES IN THE RAT TESTIS STRUCTURE AFTER A PERORAL ADMINISTRATION IN DRIKING WATER Róbert Toman*1, Mária Adamkovičová2, Peter Massányi2, Michal Cabaj1, Norbert Lukáč2, Monika Martiniaková3, Radoslav Omelka3 Address: 1Slovak University of Agriculture, Faculty of Agrobiology and Food Sources, Department of Veterinary Disciplines, Tr. A. Hlinku 2, 94976 Nitra, Slovak Republic 2 Slovak University of Agriculture, Faculty of Biotechnology and Food Sciences, Department of Animal Physiology, Tr. A. Hlinku 2, 94976 Nitra, Slovak Republic 3 Constantine The Philosopher University, Faculty of Natural Sciences, Tr. A. Hlinku 1, 94974 Nitra, Slovak Republic *Corresponding author: ABSTRACT The present study was carried out to elucidate the effects of heavy metal cadmium (Cd) and a nonselective organophosphorus insecticide diazinon (DZN) administration on the testis structures in adult male rats in subchronic toxicity experiments. A total of 40 Wistar 4 weeks old rats were randomized into 4 groups of 10 animals each and dosed with cadmium (Cd) 30 mg/l (group A), diazinon (DZN) 40 mg/l (group B), and in combination of Cd and DZN (30 and 40 mg/l, respectively, group C) per os in drinking water for 90 days. Testicular histology using a light microscopy and morphometry using PC morphometric software M.I.S. Quick Photo were evaluated. The morphometric data supported histological observations at tubular and interstitial level. Reduced seminiferous epithelium (P<0.001) in Cd group showed desquamation of germ cells, cellular degeneration and necrosis. Increase in epithelial vacuoles and dilated blood vessels relative volume (P<0.001) were observed in all experimental groups. Cd and DZN and their combination exerted changes in the reproductive parameters which could be subsequently negatively related to male fertility. These data provide a novel 564 JMBFS / Toman et al. 2012 : 2 (2) 564-575 insight into the reproductive toxicology of Cd-DZN in male rats. However, results did not indicate synergistic or additional effect of simultaneous administration of both toxicants. Keywords: testis, histology, morphometry, rat, cadmium, diazinon, fertility INTRODUCTION Global concerns have been raised in recent years over possible adverse effects that may result from exposure to chemicals that have the potential to interfere with the endocrine system (Courant et al., 2007). While some potential environmental hazards involve significant exposure to only a single compound, the most instances of environmental contamination involve concurrent or sequential exposures to a mixture of compounds that may induce similar or dissimilar effects over exposure periods ranging from short-term to lifetime (U.S. EPA, 2000). The toxicity can be modified by simultaneous or sequential exposure to multiple agents in the environment. For some combined or mixed exposures the health effects may increase more than what would be expected from simply adding the effects of the individual components, therefore there is a concern that several less studied complex exposures may have a large impact on our health as a result of combined or mixed effects (Silins and Högberg, 2011). Predicting risk from exposure to chemical mixtures is complex, as chemicals in mixtures can interact in terms of both toxicokinetics and toxicodynamics (Meek et al., 2011). Heavy metals could adversely affect the male reproductive system, either by causing hypothalamic-pituitary axis disruption or by directly affecting spermatogenesis, resulting in impair semen quality (Mendiola et al., 2011), environmental cadmium (Cd) exposures may contribute significantly to reduced human male sperm concentration and sperm motility (Benoff et al., 2009). Exposure to cadmium has been reported to induce testicular and epididymal damage (Toman et al., 2008; De Souza Predes et al., 2010) and may contribute to male infertility by reducing sperm quality in both humans and rodents (Benoff, et al., 2009; Xu, 2001, Roychoudhury, 2010). Diazinon (O,O-diethyl O-2isopropyl-6-methyl pyrimidinyl-4-g-1-phosphorothioate) is a nonselective organophosphorus insecticide primarily used for agricultural purposes and is released to the environment through spraying on a wide variety of agricultural crops and at agricultural sites for pest control (ATSDR, 2008). Diazinon induces several neurological and endocrine alterations in humans and different wildlife species (Kojima et al., 2005; Maxwell and Dutta, 2005; Fattahi et al., 565 JMBFS / Toman et al. 2012 : 2 (2) 564-575 2009), resulting in reduction in genital weights, reduced sperm motility and viability, and increased sperm morphological abnormalities (Abd El-Aziz et al., 1994). Diazinon may also probably enhance the oxidative stress, altering the antioxidant enzymes which again may have adverse effects on normal cell association affecting the seminiferous tubular architecture (Damodar et al., 2012). It is known that environmental contaminants are responsible for a range of noxious effects on various health aspects but little information is available on their possible combined effect on male reproductive function. Hence the objective of the present study was to assess the histological aspects of testis and seminiferous tubular morphometric and cyto-architectural components on exposure to cadmium and diazinon after a sole or simultaneous intake, as both compounds are regularly found in the animal and human food. MATERIAL AND METHODS Experimental design Young, 4 weeks old male rats of the Wistar strain were randomly divided into four groups of ten animals. The males were housed individually in plastic cages under constant temperature (20-22°C), humidity (55±10%), and 12/12 h cycle of light and darkness with access to food (feed mixture M3, Machal, Brno, Czech Republic) and drinking water ad libitum. All experiments were conducted in accordance with accepted standards of animal care in accredited laboratory (SK PC 50004, SUA Nitra). Rats in the group A were dosed with cadmium (CdCl2, Reachem, Bratislava, Slovak Republic) at 30 mg/L drinking water for 90 days. Group B was exposed to diazinon (Sigma-Aldrich, Seelze, Germany) at 40 mg/L drinking water for 90 days and rats in the group C were given a mixture of cadmium and diazinon (30 mg/L and 40 mg/L, respectively) in drinking water for 90 days. The fourth group D served as a control and received drinking water with no cadmium or diazinon addition. Animals were anaesthetized with ether and sacrificed 90 days after the start of the experiment. Testis histology Testes were removed from the scrotum, freed from adherent tissues and weighed. Left testes were fixed in modified Davidson’s solution (Latendresse et al., 2002) and after processing, tissues were embedded in paraffin, sectioned on a microtome into 5 μm sections and stained with haemat (...truncated)