Effect of zearalenone on reproductive parameters and expression of selected testicular genes in mice

Antimicrobial and Mycotoxin Reducing Properties of Lactic Acid Bacteria and Their Influence on Blood and Feces Parameters of Newborn Calves

The aim of this study was to evaluate the influence of in acid whey (AW) multiplied Lactiplantibacillus plantarum LUHS135 (L.pl135), Lacticaseibacillus paracasei LUHS244 (L.pc244), and their biomass combination on newborn calves' feces and blood parameters. Additionally, the antimicrobial and mycotoxin-reducing properties and the resistance to antibiotics of the tested lactic acid bacteria (LAB) strains were analyzed. In order to ensure effective biomass growth in AW, technological parameters for the supplement preparation were selected. Control calves were fed with a standard milk replacer (SMR) and treated groups (from the 2nd day of life until the 14th day) were supplemented with 50 mL of AWL.pl135, AWL.pc244, and AWL.pl135×L.pc244 (25 mL AWL.pl135 + 25 mL AWL.pc244) in addition to SMR. It was established that L.pl135 and L.pc244 possess broad antimicrobial activities, are non-resistant to the tested antibiotics, and reduce mycotoxin concentrations in vitro. The optimal duration established for biomass growth was 48 h (LAB count higher than 7.00 log10 CFU mL-1 was found after 48 h of AW fermentation). It was established that additional feeding of newborn calves with AWL.pl135, AWL.pc244, and AWL.pl135×L.pc244 increased lactobacilli (on average by 7.4%), and AWL.pl135 and AWL.pc244 reduced the numbers of Enterobacteriaceae in calves' feces. The tested supplements also reduced the lactate concentration (on average, by 42.5%) in calves' blood. Finally, the tested supplements had a positive influence on certain health parameters of newborn calves; however, further research is needed to validate the mechanisms of the beneficial effects.

Ex vivo effects of bisphenol A or zearalenone on the prepubertal rat testis

Bisphenol A (BPA) and zearalenone (ZEA) are two widespread xenoestrogens involved in male reproductive disorders. Few studies investigated the effects of these compounds on the prepubertal testis, which is highly sensitive to endocrine disruptors such as xenoestrogens. An ex vivo approach was performed to evaluate the effects of BPA or ZEA (10^-11, 10^-9, 10^-6 M) on the testes of 20 and 25 dpp rats. To investigate the involvement of classical nuclear ER-mediated estrogen signaling in these effects, pre-incubation with an antagonist (ICI 182.780 10^-6M) was performed. BPA and ZEA have similar effects on spermatogenesis- and steroidogenesis-related endpoints in the immature testis, but our study highlights different age-dependent patterns of sensitivity to each compound during the prepubertal period. Moreover, our results indicate that the effects of BPA are likely to be induced by nuclear ER, whereas those of ZEA appear to involve other mechanisms.

Zearalenone damages the male reproductive system of rats by destroying testicular focal adhesion

Zearalenone (ZEA), a common mycotoxin in animal feed, is harmful to public health and causes huge economic losses. The potential target proteins of ZEA and its derivatives were screened using the PharmMapper database and the related genes (proteins) of the testis were obtained from Genecards. We obtained 144 potential targets of ZEA and its derivatives related to the testis using Venn diagrams. The PPI analysis showed that ZEA had the most targets in testis, followed by ZAN, α-ZAL, β-ZEL, α-ZEL, and β-ZAL. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses evaluated the metabolic and cancer pathways. We further screened four hub genes: RAC3, CCND1, EP300, and CTNNB1. Eight key biological processes were obtained by GO analysis, and four important pathways were identified by KEGG analysis. Animal and cell experimental results confirmed that ZEA could inhibit the expression of four key KEGG pathway protein components and four hub proteins that interfere with cell adhesion by inhibiting the focal adhesion structure of the testis, Leydig cells, and Sertoli cells. Collectively, our findings reveal that the destruction of the focal adhesion structure in the testis is the mechanism through which ZEA damages the male reproductive system.

Zearalenone Promotes Uterine Development of Weaned Gilts by Interfering with Serum Hormones and Up-Regulating Expression of Estrogen and Progesterone Receptors

In this study, we aimed to assess the effect of diet ZEA on serum hormones, the location and expression of estrogen receptor ERα/β and progesterone receptor (PR) of the uterus in weaned piglets and to reveal the mechanism underneath. A total of 40 healthy weaned gilts were randomly allocated to basal diet supplemented with 0 (Control), 0.5 (ZEA0.5), 1.0 (ZEA1.0) and 1.5 (ZEA1.5) mg ZEA/kg and fed individually for 35 days. Meanwhile, the porcine endometrial epithelial cells (PECs) were incubated for 24 h with ZEA at 0 (Control), 5 (ZEA5), 20 (ZEA20) and 80 (ZEA80) μmol/L, respectively. The results showed that nutrient apparent digestibility (CP and GE), nutrient apparent availability (ME/GE, BV and NPU), the uterine immunoreactive integrated optic density (IOD), relative mRNA and protein expression of ER-α, ER-β and PR and the relative mRNA and protein expression of ER-α and ER-β in PECs all increased linearly (p < 0.05) with ZEA. Collectively, ZEA can interfere with the secretion of some reproductive hormones in the serum and promote the expression of estrogen/progesterone receptors in the uterus and PECs. All these indicate that ZEA may promote the development of the uterus in weaned gilts through estrogen receptor pathway.

Exogenous L-Glutathione Improves Vitrification Outcomes in Murine Preimplantation Embryos

Vitrification is an important tool to store surplus embryos in assisted reproductive technology (ART). However, vitrification increases oxidative damage and results in decreased viability. Studies have reported that L-glutathione (GSH) supplementation improves the preimplantation development of murine embryos. Glutathione constitutes the major non-protein sulphydryl compound in mammalian cells, which confers protection against oxidative damage. However, the effect of GSH supplementation on embryonic vitrification outcomes has yet to be reported. This study aims to determine whether GSH supplementation in culture media improves in vitro culture and vitrification outcomes, as observed through embryo morphology and preimplantation development. Female BALB/c mice aged 6−8 weeks were superovulated through an intraperitoneal injection of 10 IU of pregnant mare serum gonadotrophin (PMSG), followed by 10 IU of human chorionic gonadotrophin (hCG) 48 h later. The mated mice were euthanized by cervical dislocation 48 h after hCG to harvest embryos. Two-cell embryos were randomly assigned to be cultured in either Group 1 (GSH-free medium), Group 2 (GSH-free medium with vitrification), Group 3 (0.01 mM GSH-supplemented medium), or Group 4 (0.01 mM GSH-supplemented medium with vitrification). Non-vitrified (Groups 1 and 3) and vitrified (Groups 2 and 4) embryos were observed for morphological quality and preimplantation development at 24, 48, 72, and 96 h. In the non-vitrified groups, there were significant increases in the number of Grade-1 blastocysts in GSH cultures (p < 0.05). Similarly, in the vitrified groups, GSH supplementation was also seen to significantly increase blastocyst formation. Exogenous GSH supplementation resulted in a significant increase in intracellular GSH, a release of cytochrome c from mitochondria, and a parallel decrease in intracellular reactive oxygen species (ROS) levels in vitrified eight-cell embryos (p < 0.05). GSH supplementation was shown to upregulate Bcl2 expression and downregulate Bax expression in the vitrified preimplantation embryo group. The action of exogenous GSH was concomitant with an increase in the relative abundance of Gpx1 and Sod1. In conclusion, our study demonstrated the novel use and practical applicability of GSH supplementation for improving embryonic cryotolerance via a decrease in ROS levels and the inhibition of apoptotic events by improvement in oxidative status.

Effects of Zearalenone on Production Performance, Egg Quality, Ovarian Function and Gut Microbiota of Laying Hens

Zearalenone (ZEN) is a ubiquitous contaminant in poultry feed, since ZEN and its metabolites can interfere with estrogen function and affect the reproductive ability of animals. The estrogen-like effect of ZEN on mammal is widely reported, while little information is available, regarding the effect of relatively low dose of ZEN on estrogen function and production performance of laying hens, and the relationship between them. This work was aimed to investigate the effects of ZEN on the production performance, egg quality, ovarian function and gut microbiota of laying hens. A total of 96 Hy-line brown laying hens aged 25-week were randomly divided into 3 groups including basal diet group (BD group), basal diet supplemented with 250 μg/kg (250 μg/kg ZEN group) and 750 μg/kg (750 μg/kg ZEN group) ZEN group. Here, 750 μg/kg ZEN resulted in a significant increase in the feed conversion ratio (FCR) (g feed/g egg) (p < 0.05), a decrease in the egg production (p > 0.05), albumen height and Haugh unit (p > 0.05), compared to the BD group. The serum Follicle-stimulating hormone (FSH) levels significantly decreased in ZEN supplemented groups (p < 0.05). Serum Luteinizing hormone (LH) and Progesterone (P) levels in the 750 μg/kg ZEN group were significantly lower than those in the BD group (p < 0.05). 16S rRNA sequencing indicated that ZEN reduced cecum microbial diversity (p < 0.05) and altered gut microbiota composition. In contrast to 250 μg/kg ZEN, 750 μg/kg ZEN had more dramatic effects on the gut microbiota function. Spearman’s correlation analysis revealed negative correlations between the dominant bacteria of the 750 μg/kg ZEN group and the production performance, egg quality and ovarian function of hens. Overall, ZEN was shown to exert a detrimental effect on production performance, egg quality and ovarian function of laying hens in this study. Moreover, alterations in the composition and function of the gut microbiota induced by ZEN may be involved in the adverse effects of ZEN on laying hens.

Microbial and enzymatic battle with food contaminant zearalenone (ZEN)

Zearalenone (ZEN) contamination of various foods and feeds is an important global problem. In some animals and humans, ZEN causes significant health issues in addition to massive economic losses, annually. Therefore, removal or degradation of the ZEN in foods and feeds is required to be done. The conventional physical and chemical methods have some serious issues including poor efficiency, decrease in nutritional value, palatability of feed, and use of costly equipment. Research examined microbes from diverse media for their ability to degrade zearalenone and other toxins, and the findings of several investigations revealed that enzymes produced from microbes play a significant role in the degradation of mycotoxins. In established bacterial hosts, genetically engineered technique was used to enhance heterologously produced degrading enzymes. Then, the bio-degradation of ZEN by the use of micro-organisms or their enzymes is much more advantageous and is close to nature and ecofriendly. Furthermore, an effort is made to put forward the work done by different scientists on the biodegradation of ZEN by the use of fungi, yeast, bacteria, and/or their enzymes to degrade the ZEN to non-toxic products. KEY POINTS: •Evolved microbial strains degraded ZEA more quickly •Different degrading properties were studied.

Identification of apoptotic pathways in zearalenone-treated mouse sertoli cells

Zearalenone (ZEN), one of the most prevalent non-steroidal oestrogenic mycotoxins, is primarily produced by Fusarium fungi. Due to its toxicity as an oestrogenic compound and wide distribution in feed and foods, the reproductive toxicology of ZEN exposure is of public concern. The aim of the present study was to investigate the effect of ZEN on Sertoli cells to identify apoptotic pathways induced by this compound. We found that ZEN reduced the viability and caused apoptosis in Sertoli cells in vitro. Notably, we observed that such effects were associated with a significant increase in reactive oxygen species (ROS) and the number of cells that showed positive staining for γH2AX and RAD51, enzymes essential for repairing DNA damage. There was a parallel decrease in the expression of occludin and connexin 43, proteins that are present in the testis-blood barrier and gap junctions of Sertoli cells, respectively. Overall, the present study confirms that ZEN exposure can have serious deleterious effects on mammalian Sertoli cells and offers novel insight about its molecular targets in these cells.

Pyroglutamylated RFamide peptide (QRFP): Role in early testicular development in relation to Sertoli cell maturation in prepubertal mice

QRFP, an orexigenic neuropeptide, binds to its cognate receptor GPR103 and regulates various biological functions. We have recently shown that QRFP and its receptor are present in mice testes and that their expression is high during early postnatal period. The present study aimed to investigate the effect of sustained high level of QRFP on Sertoli cells proliferation and differentiation and to relate these events with germ cell differentiation and lumen formation in the seminiferous tubules in mice testes during prepubertal period. QRFP was injected intraperitoneally to male mice from postnatal day 5 to 16. Morphometric analysis and various markers related to Sertoli cell maturation (WT1, p27kip1, AMH, AR and CYP19A1) and germ cell proliferation and differentiation (PCNA, GDNF and c-Kit) were evaluated. QRFP administration caused an early lumen formation in the seminiferous tubules in testis of treated mice. Further, there was a significant increase in p27kip1 expression and a marked decrease in AMH expression in QRFP-treated mice compared to controls. However, no appreciable change was noted in AR expression in treated mice. QRFP treatment also caused an increase in c-Kit expression in treated mice compared to controls, suggesting an accelerated spermatogonial differentiation in testis of QRFP-treated mice. Taken together, the present results suggest that the prolonged high level of QRFP increases Sertoli cell maturation, which, in turn, plays a contributory role in increasing the pace of germ cell differentiation and formation of lumen in the seminiferous tubules.

Assessment of Zearalenone-Induced Cell Survival and of Global Gene Regulation in Mouse TM4 Sertoli Cells

Zearalenone (ZEA) is a non-steroidal xenoestrogen mycotoxin produced by many Fusarium fungal species, which are common contaminants of cereal crops destined for worldwide human and animal consumption. ZEA has been reported in various male reproduction dysfonctions, including decreased fertility potential. In this report, the direct effect of ZEA on the immature Sertoli TM4 cell line was evaluated. The results show that high concentrations of ZEA increase reactive oxygen species via the activation of MAPK signaling. Transcriptome analysis was performed on the TM4 cell line treated with ZEA, and genes involved in sex differentiation (Fgfr2, Igf1, Notch1, Sox9) and extracellular matrix (ECM) formation (Ctgf, Fam20a, Fbn1, Mmp9, Postn, Sparcl1, Spp1) were identified at the center of the functional protein association network, suggesting that ZEA could be detrimental to the early steps of Sertoli cell differentiation.

Zearalenone Induces Endothelial Cell Apoptosis through Activation of a Cytosolic Ca2+/ERK1/2/p53/Caspase 3 Signaling Pathway

Zearalenone (ZEN) is a mycotoxin that has been reported to damage various types of cells/tissues, yet its effects on endothelial cells (ECs) have never been investigated. Therefore, this study investigates the potential effects of ZEN using bovine aortic ECs (BAECs). In this study, we found that ZEN induced apoptosis of BAECs through increased cleavage of caspase 3 and poly ADP-ribose polymerase (PARP). ZEN also increased phosphorylation of ERK1/2 and p53, and treatment with the ERK1/2 or p53 inhibitor reversed ZEN-induced EC apoptosis. Transfection of BAECs with small interfering RNA against ERK1/2 or p53 revealed ERK1/2 as an upstream target of p53 in ZEN-stimulated apoptosis. ZEN increased the production of reactive oxygen species (ROS), yet treatment with the antioxidant did not prevent EC apoptosis. Similarly, blocking of estrogen receptors by specific inhibitors also did not prevent ZEN-induced apoptosis. Finally, chelation of cytosolic calcium (Ca²⁺) using BAPTA-AM or inhibition of endoplasmic reticulum (ER) Ca²⁺ channel using 2-APB reversed ZEN-induced EC apoptosis, but not by inhibiting ER stress using 4-PBA. Together, our findings demonstrate that ZEN induces EC apoptosis through an ERK1/2/p53/caspase 3 signaling pathway activated by Ca²⁺ release from the ER, and this pathway is independent of ROS production and estrogen receptor activation.

Gestational and pubertal exposure to low dose of di-(2-ethylhexyl) phthalate impairs sperm quality in adult mice

Di-(2-ethylhexyl)-phthalate (DEHP) is a compound widely used as a plasticizer, which can leach from plastics into the environment and thus influence human health. The aim of this study was to analyze whether exposure to an environmentally relevant dose of DEHP during mice fetal development or puberty can cause long-lasting changes detectable month/s after the last exposure. We used a DEHP concentration relevant to a daily human intake of 2.4-3 μg/kg of body weight/day. CD1 outbred mice were treated either in utero or postnatally during puberty and analyzed in adulthood. Analyzing fertility parameters using morphometric, histologic, genomic and proteomic methods we showed that DEHP exposure leads to decreased sperm concentration and quality, in both experimental groups. Moreover, the changes in anogenital distance, seminal vesicle weight, and testicular gene expression suggest a disturbance of androgen signaling in exposed animals. In conclusion, we hereby present, that the prenatal and pubertal exposure to a low dose of DEHP negatively influenced reproductive endpoints in male mice, and some of the effects were persistent until adulthood.

Zearalenone-Induced Interaction between PXR and Sp1 Increases Binding of Sp1 to a Promoter Site of the eNOS, Decreasing Its Transcription and NO Production in BAECs

Zearalenone (ZEN) is a non-steroidal mycotoxin that has various toxicological impacts on mammalian health. Here, we found that ZEN significantly affected the production of nitric oxide (NO) and the expression of endothelial NO synthase (eNOS) of bovine aortic endothelial cells (BAECs). A promoter analysis using 5′-serially deleted human eNOS promoter revealed that the proximal region (−135 to +22) was responsible for ZEN-mediated reduction of the human eNOS promoter activity. This effect was reversed by mutation of two specificity protein 1 (Sp1) binding elements in the human eNOS promoter. A chromatin immunoprecipitation assay revealed that ZEN increased Sp1 binding to the bovine eNOS promoter region (−113 to −12), which is homologous to −135 to +22 of the human eNOS promoter region. We also found that ZEN promoted the binding of the pregnane X receptor (PXR) to Sp1 of the bovine eNOS, consequently decreasing eNOS expression. This reduction of eNOS could have contributed to the decreased acetylcholine-induced vessel relaxation upon ZEN treatment in our ex vivo study using mouse aortas. In conclusion, our data demonstrate that ZEN decreases eNOS expression by enhancing the binding of PXR-Sp1 to the eNOS promoter, thereby decreasing NO production and potentially causing vessel dysfunction.

Toxicity of mycotoxins in vivo on vertebrate organisms: A review

Mycotoxins are considered to be a major risk factor affecting human and animal health as they are one of the most dangerous contaminants of food and feed. This review aims to compile the research developed up to date on the toxicological effects that mycotoxins can induce on human health, through the examination of a selected number of studies in vivo. AFB1 shows to be currently the most studied mycotoxin in vivo, followed by DON, ZEA and OTA. Scarce data was found for FBs, PAT, CIT, AOH and Fusarium emerging mycotoxins. The majority of them concerned the investigation of immunotoxicity, whereas the rest consisted in the study of genotoxicity, oxidative stress, hepatotoxicity, cytotoxicity, teratogenicity and neurotoxicity. In order to assess the risk, a wide range of different techniques have been employed across the reviewed studies: qPCR, ELISA, IHC, WB, LC-MS/MS, microscopy, enzymatic assays, microarray and RNA-Seq. In the last decade, the attention has been drawn to immunologic and transcriptomic aspects of mycotoxins' action, confirming their toxicity at molecular level. Even though, more in vivo studies are needed to further investigate their mechanism of action on human health.

ZEA-induced autophagy in TM4 cells was mediated by the release of Ca2+ activates CaMKKβ-AMPK signaling pathway in the endoplasmic reticulum

Zearalenone (ZEA) is a prevalent non-steroidal estrogenic mycotoxin produced mainly by Fusarium contamination. Our previous study showed that ZEA induces the autophagy of Sertoli cells (SCs). However, the underlying mechanisms are still unknown. Several studies have indicated that the increasing level of cytoplasmic Ca²⁺ could induce autophagy through CaMKKβ and AMPK pathways. Thus in order to investigate the potential mechanism underlying ZEA-induced autophagy, the activity of calmodulin-dependent kinase kinase β(CaMKKβ)and AMP-activated protein kinase (AMPK) signaling pathway in ZEA-infected TM4 cells was studied. In the present study, ZEA activated the CaMKKβ and AMPK signaling pathways. The AMPK inhibitor and activator significantly inhibited and stimulated the effect of ZEA on AMPK, the transformation from LC3I to LC3II, and the distribution of LC3 dots. In addition, cytosolic calcium (Ca²⁺) was increased gradually with the concentration of ZEA. After treatment of ZEA-infected cells with 1, 2-bis (2-aminophenoxy) ethane-N, N, N', N'- tetraacetic acid- tetraac etoxymethyl ester (BAPTA-AM) and 2-aminoethyl diphenylborinate (2-APB), the intracellular concentration of Ca²⁺ reduced significantly. Also, the activities of CaMKKβ and AMPK and subsequent autophagy decreased. Moreover, the antioxidant NAC significantly decreased activities of AMPK and autophagy -related protein. Therefore, it can be speculated that ROS- mediated ER-stress induced by ZEA activates AMPK via Ca²⁺-CaMKKβ leading to autophagy in TM4 cells.

The role of the poultry industry on kidney and genitourinary health in Pakistan

Pakistan is experiencing a "double burden'' of disease. Under-development is associated with illnesses like infections and nutritional deficiency, and is accompanied with diseases linked with development, such as diabetes, hypertension, cancer and chronic kidney disease. In Pakistan, renal and genitourinary diseases are an important, unaddressed health issues. Chronic kidney disease of unknown etiology (CKDu) is a recognized form of renal failure in Pakistan. A possible cause of CKDu is toxins such as arsenic, cadmium, lead and other heavy metals associated with renal and genitourinary diseases. The poultry industry is an important source of both heavy metal toxins and also mycotoxins spread in the process of farming. Of the numerous mycotoxins, zearalenone and ochratoxin are well-known for their hazardous effects on genitourinary and renal parenchyma respectively. We reviewed the literature using PubMed and Google Scholar databases for levels of these toxins in various constituents of chicken farming like chicken feed, meat, litter and human drinking water contamination in various parts of the country. We found that these toxins are in higher levels than recommended.

Integration of proteome and transcriptome data reveals the mechanism involved in controlling of Fusarium graminearum by Saccharomyces cerevisiae

BACKGROUND

It has been reported that antagonistic microorganisms could effectively control the infection of Fusarium graminearum. However, there is limited information on the control of F. graminearum by Saccharomyces cerevisiae, while the possible control mechanisms involved through proteomic and transcriptomic techniques have also not been reported.

RESULTS

The results of this study showed that S. cerevisiae Y-912 could significantly inhibit the growth of F. graminearum Fg1, and the spore germination rate and germ tube length of F. graminearum Fg1 were also significantly inhibited by S. cerevisiae Y-912. Proteomic analysis revealed that differentially expressed proteins which were made of some basic proteins and enzymes related to basal metabolism, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate mutase (PGAM), enolase (ENO), fructose diphosphate aldolase (FBA) and so on, were all down-regulated. The transcriptomics of F. graminearum control by S. cerevisiae was also analyzed.

CONCLUSION

The control mechanism of S. cerevisiae Y-912 on F. graminearum Fg1 was a very complex material and energy metabolic process in which the related proteins and genes involved in the glycolytic pathway, tricarboxylic acid (TCA) cycle and amino acid metabolism were all down-regulated. © 2019 Society of Chemical Industry.

Updates on the Effect of Mycotoxins on Male Reproductive Efficiency in Mammals

Mycotoxins are ubiquitous and unavoidable harmful fungal products with the ability to cause disease in both animals and humans, and are found in almost all types of foods, with a greater prevalence in hot humid environments. These mycotoxins vary greatly in structure and biochemical effects; therefore, by better understanding the toxicological and pathological aspects of mycotoxins, we can be better equipped to fight the diseases, as well as the biological and economic devastations, they induce. Multiple studies point to the association between a recent increase in male infertility and the increased occurrence of these mycotoxins in the environment. Furthermore, understanding how mycotoxins may induce an accumulation of epimutations during parental lifetimes can shed light on their implications with respect to fertility and reproductive efficiency. By acknowledging the diversity of mycotoxin molecular function and mode of action, this review aims to address the current limited knowledge on the effects of these chemicals on spermatogenesis and the various endocrine and epigenetics patterns associated with their disruptions.

Pubertal exposure to low doses of zearalenone disrupting spermatogenesis through ERα related genetic and epigenetic pathways

Endocrine disruptor zearalenone (ZEA) has been found to damage the reproductive system especially spermatogenesis. In our previous report, we have found that low dose (lower than No-Observed Effect Level, NOEL) ZEA exposure disturbed mouse spermatogenesis and diminished mouse semen quality. The purpose of current investigation was to explore the underlying mechanisms of pubertal low dose ZEA exposure upsetting spermatogenesis. And it was demonstrated that pubertal low dose ZEA exposure disrupted the meiosis process and the important genetic pathways to inhibit the spermatogenesis and even to diminish the semen quality with the decrease in spermatozoa motility and concentration. The DNA methylation markers 5mC and 5hmC were decreased, the histone methylation marker H3K27 was increased, at the same time estrogen receptor alpha was diminished in mouse testis after pubertal low dose ZEA exposure. The data indicate that the disruption in spermatogenesis by pubertal low dose ZEA exposure may be through the alterations in genetic and epigenetic pathways, and the interactions with estrogen receptor signaling pathway. Therefore, we should pay great attention on ZEA exposure to reduce its adverse impacts on male reproductive health.

Gestational exposure to low-dose zearalenone disrupting offspring spermatogenesis might be through epigenetic modifications

Zearalenone (ZEA), a F-2 mycotoxin produced by Fusarium, has been found to be an endocrine disruptor through oestrogen receptor signalling pathway to impair spermatogenesis. The disruption on reproductive systems by ZEA exposure might be transgenerational. In our previous report, we have found that low dose (lower than no-observed effect level, NOEL) of ZEA impaired mouse spermatogenesis and decreased mouse semen quality. The purpose of the current investigation was to explore the impacts of low-dose ZEA on spermatogenesis in the offspring after prenatal exposure and the underlying mechanisms. And it demonstrated that prenatal low-dose ZEA exposure disrupted the meiosis process to inhibit the spermatogenesis in offspring and even to diminish the semen quality by the decrease in spermatozoa motility and concentration. The DNA methylation marker 5hmC was decreased, the histone methylation markers H3K9 and H3K27 were elevated, and oestrogen receptor alpha was reduced in the offspring testis after prenatal low-dose ZEA exposure. The data suggest that the disruption in spermatogenesis by prenatal low-dose ZEA exposure may be through the modifications on epigenetic pathways (DNA methylation and histone methylation) and the interactions with oestrogen receptor signalling pathway. Moreover, in the current study, the male offspring were indirectly exposed to low-dose ZEA through placenta and the spermatogenesis in offspring was disrupted which suggested that the toxicity of ZEA on reproductive systems was very severe. Therefore, we strongly recommend that greater attention should be paid to this mycotoxin to minimize its adverse impact on human spermatogenesis.

The flavonoid chrysin protects against zearalenone induced reproductive toxicity in male mice

The mycotoxin zearalenone (ZEA) has strong estrogenic effects and elicits reproductive toxicity. Chrysin is a natural flavonoid found in many plant and has a broad range of pharmacological activities, including anticancer, antioxidant and anti-inflammatory. The present study aimed to investigate the potential protective effects of chrysin against ZEA toxicity. Mice received chrysin (5 or 20 mg/kg; i.g.) for ten days, and then received a single injection of ZEA (40 mg/kg). Two days thereafter, blood and testes were collected. ZEA decreased number and motility of sperm, plasma testosterone levels, enzymatic (glutathione peroxidase, glutathione reductase, glutathione-S-transferase) and non-enzimatic defenses (reduced glutathione). Moreover, ZEA increased 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine levels, myeloperoxidase activity and levels of proinflammatory cytokines (interleukins-1β and 6, tumor necrosis factor alpha). ZEA also decreased levels of anti-inflammatory cytokine interleukin-10 and increased activity of caspases 3 and 9. Chrysin treatment increased the number and motility of sperm, testosterone levels, restored antioxidant defenses and reduced the inflammation and apoptosis process. In summary, chrysin attenuated the toxic effects caused by ZEA in blood and testes of mice, suggesting a potential preventive treatment against the deleterious effects of ZEA.

Cytotoxic and inflammatory effects of individual and combined exposure of HepG2 cells to zearalenone and its metabolites

Zearalenone (ZEA), a mycotoxin produced by several Fusarium spp., is most commonly found as a contaminant in stored grain. ZEA derivatives (α-zearalenol (α-ZOL), β-zearalenol (β-ZOL)) can also be produced by Fusarium spp. in corn stems infected by fungi in the field. Also, following oral exposure, zearalenone is metabolized in various tissues, particularly in the liver, the major metabolites being α-ZOL and β-ZOL. The co-exposure of cells to mixture of a combination of mycotoxins may cause an increase of toxicity produced by these mycotoxins. In this in vitro study, we investigated the combined effects of ZEA, α-ZOL, β-ZOL in binary mixtures on the viability and inflammatory response of human liver cancer cell line (HepG2). Cell viability was assessed after 72 h using a neutral red assay. Effect of the toxins and their binary combinations on the expression of genes involved in inflammation (IL-1β, TNF-α, and IL-8) were assessed through qPCR. Our viability data showed that irrespective of the toxin combinations, the toxins have synergistic effect. ZEA + α-ZOL and ZEA + β-ZOL mixtures have induced a slight to high antagonistic response on inflammatory cytokines at low concentrations that have turned into strong synergism for high concentrations. α-ZOL + β-ZOL showed antagonistic effects on inflammation for IL-1β and TNF-α, but act synergic for IL-8 at high toxin concentrations. This study clearly shows that co-contamination of food and feed with ZEA metabolites should be taken into consideration, as the co-exposure to mycotoxins might result in stronger adverse effect than resulted from the exposure to individual toxin.

Zearalenone and its metabolites: Effect on human health, metabolism and neutralisation methods

Mycotoxins are natural compounds produced as secondary metabolites by mold fungi belonging mainly to the Fusarium family, commonly found on plants such as corn or small grains in the temperate climate zone. One of these mycotoxins is zearalenone, which is classified as a xenoestrogen, an exogenous compound which resembles the structure of naturally occurring estrogens with its chemical structure. This property of zearalenone determines its ability to bind to estrogen receptors of cell and its bioaccumulation. This leads to disorders of the hormonal balance of the body, which in consequence may lead to numerous diseases of reproductive system such as prostate, ovarian, cervical or breast cancers. High risk posed by long-term exposure to contaminated food forces the modern science to develop and implement effective methods of zearalenone neutralisation. This work is a review of current state of knowledge on toxic effects of zearalenone, its metabolism in biological systems and proposed methods of its neutralisation.

Mycotoxin exposure and adverse reproductive health outcomes in Africa: a review

It is well established that mycotoxin exposure can have adverse effects on reproductive health resulting to poor reproductive potential. The most studied mycotoxin in relation to poor reproductive health in humans is aflatoxin, although fumonisins, trichothecenes and zearalenone have also been reported to impair reproductive function and cause abnormal foetal development. These potent fungal toxins contaminate many food products making them a prominent agricultural, food safety and public health challenge, especially in Africa due to little or lack of mycotoxin regulation in agricultural products. Neonates can be exposed to aflatoxins in utero, as the toxins pass from mother to the foetus through the placenta. This exposure may continue during breast feeding, to the introduction of weaning foods, and then foods taken by adults. The consequences of aflatoxin exposure in mothers, foetus and children are many, including anaemia in pregnancy, low birth weight, interference with nutrient absorption, suppression of immune function, child growth retardation and abnormal liver function. In males, reports have indicated a possible relationship between aflatoxin exposure and poor sperm quality culminating in infertility. Maternal exposure to fumonisin during early pregnancy has been associated with increased risk of neural tube defects among newborns in regions where maize is the common dietary staple with the possibility of chronic fumonisin exposure. Furthermore, zearalenone has been linked to precocious puberty and premature thelarche in girls, correlating with extremely high serum oestrogen levels. This review presents an overview of the several reports linking aflatoxins, fumonisins, trichothecenes, and zearalenone exposure to poor reproductive health outcomes in Africa, with emphasis on birth outcomes, foetal health and infertility.

The hypothalamic neuropeptide orexin A- a possible regulator in glucose homeostasis and germ cell kinetics in adult mice testes

Orexin A (OXA), a hypothalamic neuropeptide, regulates food intake, sleep-wake cycle and energy balance by binding to its receptor (OX1R). Apart from brain, OXA and OX1R are also present in peripheral organs including reproductive tissues. Mammalian reproduction depends on uptake and proper utilization of glucose in the testes. This study, therefore, examined role of OXA/OX1R system in regulation of glucose homeostasis in adult mouse testis under in vivo and ex vivo conditions. Binding of OXA to OX1R was blocked using an OX1R antagonist, SB-334867. Mice were given a single bilateral intratesticular injection of the antagonist at doses of 4 and 12μg/mouse and sacrificed 24 h post-injection. In order to understand the direct role of OXA in testes of adult mice, an ex vivo experiment was performed where binding of OXA to OX1R in the testis was blocked by using the same OX1R antagonist. The antagonist treatment affected testicular glucose and lactate concentration with concomitant down-regulation in the expression of glucose transporters 3 and 8. A decreased activity in lactate dehydrogenase enzyme and imbalance between germ cell survival and proliferation were also noted in testes in treated mice. The results of ex vivo study supported the results obtained from in vivo study. The findings thus suggest involvement of OXA/OX1R system in regulation of testicular glucose homeostasis and germ cell kinetics in adult mice.

Comparative Analysis of Zearalenone Effects on Thyroid Receptor Alpha (TRα) and Beta (TRβ) Expression in Rat Primary Cerebellar Cell Cultures

Thyroid receptors play an important role in postnatal brain development. Zearalenone (ZEN), a major mycotoxin of Fusarium fungi, is well known to cause serious health problems in animals and humans through various mechanisms, including the physiological pathways of thyroid hormone (TH). In the present study, we aimed to investigate the expression of thyroid receptors α (TRα) and β (TRβ) in primary cerebellar neurons in the presence or absence of glia and following ZEN treatment, using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot. Primary cerebellar granule cells were treated with low doses of ZEN (0.1 nM) in combination with physiologically relevant concentrations of l-thyroxine (T4), 3,3′,5-triiodo-l-thyronine (T3) and 17β-estradiol (E2). Expression levels of TRα and TRβ at mRNA and protein levels were slightly modified by ZEN administered alone; however, along with thyroid and steroid hormones, modelling the physiological conditions, expression levels of TRs varied highly depending on the given treatment. Gene expression levels were also highly modulated by the presence or absence of glial cells, with mostly contrasting effects. Our results demonstrate divergent transcriptional and translational mechanisms involved in the expression of TRs implied by ZEN and hormonal milieu, as well as culturing conditions.

Effects of Zearalenone Exposure on the TGF-β1/Smad3 Signaling Pathway and the Expression of Proliferation or Apoptosis Related Genes of Post-Weaning Gilts

Zearalenone (ZEA) is an estrogenic toxin produced by Fusarium species, which is widely distributed and posed a great health risk to both humans and farm animals. Reproductive disorders associated with ZEA such as premature puberty, infertility and abortion have plagued the animal husbandry, but the molecular mechanism is unclear. Because transforming growth factor-β1 (TGF-β1) signaling pathway is involved in the proliferation and apoptosis of cells, proliferating cell nuclear antigen (PCNA), B-cell lymphoma/leukemia-2 (BCL-2) and BCL-2 associated X protein (BAX) that all play indispensable roles in the normal development of the uterus, it is hypothesized that ZEA induces reproductive disorders is closely related to the expression of these genes. The objective of this study was to assess the effects of dietary ZEA at the concentrations of 0.5 to 1.5 mg/kg on the mRNA and protein expression of these genes in the uteri of post-weaning gilts and to explore the possible molecular mechanism. Forty healthy post-weaning female piglets (Duroc × Landrace × Large White) aged 38 d were randomly allocated to basal diet supplemented with 0 (Control), 0.5 (ZEA0.5), 1.0 (ZEA1.0), or 1.5 (ZEA1.5) mg/kg purified ZEA, and fed for 35 d. Piglets were euthanized at the end of the experiment and samples were taken and subjected to immunohistochemistry, qRT-PCR and Western blot analyses. The relative mRNA expressions of PCNA, BCL-2 and Smad3 in the uteri of post-weaning gilts increased linearly (p < 0.05) and quadratically (p < 0.05) as ZEA concentration increased in the diet. The relative protein expressions of PCNA, BAX, BCL-2, TGF-β1, Smad3, and phosphorylated Smad3 (p-Smad3) in the uteri of post-weaning gilts increased linearly (p < 0.05) and quadratically (p < 0.001) with an increasing level of ZEA. The results showed that uterine cells in the ZEA (0.5–1.5 mg/kg) treatments were in a high proliferation state, indicating that ZEA could accelerate the proliferation of uteri and promote the development of the uteri. At the same time, the results suggested that ZEA activates the TGF-β1/Smad3 signaling pathway, suggesting it plays an important role in accelerating the development of the uterus.

The dose-dependent effect of zearalenone on mitochondrial metabolism, plasma membrane permeabilization and cell cycle in human prostate cancer cell lines

Zearalenone (ZEA) is a nonsteroidal mycotoxin produced by several fungi of the genus Fusarium spp. It is known to play various roles in the regulation of the prostate cancer cell cycle, including carcinogenesis. The present study evaluates the influence of ZEA on the mitochondrial metabolism, plasma membrane permeabilization and cell cycle of prostate cancer cells. At concentrations of 100 nM and 0.3 nM, ZEA caused a decrease in the oxidative activity of mitochondria, as well as increases in LDH release, apoptosis induction and the number of cells in the G0/G1 phase. The opposite effect was observed for lower concentrations (0.1 nM and 0.001 nM). These in vitro studies indicate that ZEA might have pro- and antiproliferative properties in prostate cancer cells, at concentrations 0.1 nM, 0.001 nM and 0.3 nM, 100 nM, respectively.

Nonmonotonic responses to low doses of xenoestrogens: A review

Xenoestrogens (XEs) mimic or block the synthesis, metabolism and transport of normal endogenous hormones, disturbing normal endocrine function. The available data on the nonmonotonic estrogenic effects of low doses of many XEs are reviewed, covering in vitro, in vivo and epidemiological studies. The observed nonmonotonic patterns of the dose-response curves are discussed, along with possible underlying mechanisms. This review is intended to provide guidance for harm predication and to suggest prevention measures.

Of Oestrogens and Sperm: A Review of the Roles of Oestrogens and Oestrogen Receptors in Male Reproduction

The crucial role that oestrogens play in male reproduction has been generally accepted; however, the exact mechanism of their action is not entirely clear and there is still much more to be clarified. The oestrogen response is mediated through oestrogen receptors, as well as classical oestrogen receptors’ variants, and their specific co-expression plays a critical role. The importance of oestrogen signalling in male fertility is indicated by the adverse effects of selected oestrogen-like compounds, and their interaction with oestrogen receptors was proven to cause pathologies. The aims of this review are to summarise the current knowledge on oestrogen signalling during spermatogenesis and sperm maturation and discuss the available information on oestrogen receptors and their splice variants. An overview is given of species-specific differences including in humans, along with a detailed summary of the methodology outcome, including all the genetically manipulated models available to date. This review provides coherent information on the recently discovered mechanisms of oestrogens’ and oestrogen receptors’ effects and action in both testicular somatic and germ cells, as well as in mature sperm, available for mammals, including humans.

Exposure assessment of dogs to mycotoxins through consumption of dry feed

BACKGROUND

The Brazilian exportation of pet food has shown high growth rates in the last two years and determination of the exposure degree is one of the most important parameters for the risk assessment of chemical compounds. In this study the exposure degree of dogs to mycotoxins was estimated and acceptable daily intake (ADI) and safe pet dietary level (SPDL) were calculated. Thus the natural occurrence of fumonisins, zearalenone and aflatoxins was evaluated in 100 dry dog feed samples provided by pet owners in Paraná State, Brazil.

RESULTS

Despite the high frequency of fumonisins (68%), zearalenone (95%) and aflatoxins (68%) in feed samples, the mean levels detected were low. ADI for fumonisins and zearalenone was 20.0 and 1.00 µg kg(-1) body weight (BW) day(-1) respectively and SPDL for fumonisins was 2000 µg kg(-1) feed. The probable daily intake values (1.83 µg fumonisins, 0.93 µg zearalenone and 0.02 µg aflatoxins kg(-1) BW day(-1) ) were low.

CONCLUSION

The exposure degree of dogs could be assumed to be very low. However, the co-occurrence of these three or other mycotoxins, and possible synergic or additive effects, should be taken into account when determining the maximum allowed levels or risk assessment. © 2016 Society of Chemical Industry.

Zearalenone and 17 β-estradiol induced damages in male rats reproduction potential; evidence for ERα and ERβ receptors expression and steroidogenesis

The estrogen receptors (ERs)-dependent effects of Zearalenone (ZEA) on structure and function of the testis as well as sperm parameters were compared with 17-β estradiol as endogenous substance. For this purpose, 30 mature male rats were assigned into five groups as; control (appropriate volume of normal saline, i. p.), ZEA-received (1, 2 and 4 mg/kg, b. w., i. p.) and 17 β-estradiol (E2)-received (appropriate dose of 0.1 mg/kg, i. p.). Following 28 days, the mRNA levels of estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) in the testis and sperms and the expression of them at protein levels in testicles were estimated. Mitochondrial content of germinal epithelium, Leydig cells steroid foci, sperm quality parameters and serum level of testosterone were assessed. Fluorescent techniques were used for analyzing apoptosis and mRNA damage in necrotic cells. ZEA reduced the mRNA and protein levels of ERα in testicles while up-regulated the ERβ expression. The mRNA level of ERα decreased in sperms of ZEA and E2-received animals. No remarkable changes were found for ERβ expression in sperms from ZEA and E2-received animals. ZEA reduced the Leydig cells steroidogenesis, mitochondrial content of germinal cells and elevated cellular apoptosis and necrosis dose-dependently. E2 reduced the testosterone concentration, enhanced the apoptosis and reduced sperm quality. Our data suggest that ZEA-induced detrimental effects in the structure and function of testis, may attribute to changing the ERs expression at mRNA and translational level.

Biodegradation of zearalenone by Saccharomyces cerevisiae: Possible involvement of ZEN responsive proteins of the yeast

The mycotoxin zearalenone, also known as F-2 mycotoxin or RAL is a potent estrogenic metabolite produced by some Gibberella and Fusarium species. It is a common contaminant of cereal crops, livestock and poultry products. However, detoxification of zearalenone (ZEN) remains a challenge. Recently, biological approach for ZEN detoxification is being explored. In this study, we investigated the biodegradation of ZEN by using Saccharomyces cerevisiae and the possible mechanisms involved. The findings revealed that, after 48h of incubation of S. cerevisiae in combination with ZEN, the ZEN was completely degraded by S. cerevisiae. On the contrary, heat-killed cells and cell-free culture filtrates of S. cerevisiae could not degrade ZEN. Furthermore, addition of cycloheximide to S. cerevisiae combined with ZEN at time 0h prevented ZEN degradation, while addition of cycloheximide at 12h significantly slowed down degradation. The results also indicated cellular proteomics of S. cerevisiae. Several differential proteins were identified, most of which were related to basic metabolism.

BIOLOGICAL SIGNIFICANCE

The findings revealed that, after 48h of incubating ZEN together with S. cerevisiae, ZEN was completely degraded by S. cerevisiae. The mechanisms involved in the degradation of ZEN by S. cerevisiae may be the production of associated intracellular and extracellular enzymes, which have the ability to degrade ZEN. In addition, there were some functional proteins produced by S. cerevisiae, indicating that the basic metabolism of S. cerevisiae was improved when ZEN was added. This novel discovery by the authors, will greatly contribute to the field of biodegradation of mycotoxin by antagonists. The authors also believed this innovation will open the grounds for further research and improvement of S. cerevisiae in the field of biodegradation.

Quaternary ammonium disinfectants cause subfertility in mice by targeting both male and female reproductive processes

Alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC) are common ingredients in household bathroom and kitchen cleaning sprays. ADBAC+DDAC cause reproductive toxicity in mice. The aim of the present study was to investigate gender-specific reproductive effects from ADBAC+DDAC. Female reproduction was assessed through ovulation, oocyte implantation, and estrus cycling. Male reproductive function was assessed by sperm concentration, motility, and viability. Numbers of corpora lutea were not different after 2 weeks, but decreased after 8 weeks of ADBAC+DDAC exposure. Dams exposed for 5 weeks to ADBAC+DDAC spent significantly less time in estrus. ADBAC+DDAC exposed males exhibited declines in both sperm concentration and motility, but not sperm viability. Subfertility in mice from ADBAC+DDAC exposure is, therefore, mediated through reproductive disturbances in both females and males. While the effect of ADBAC+DDAC exposure on human health is unclear, widespread exposure necessitates further consideration of their potential reproductive toxicity.

The effect of in vivo exposure to zearalenone on cytokine secretion by Th1 and Th2 lymphocytes in porcine Peyer's patches after in vitro stimulation with LPS

Most research studies investigating the estrogenic effects of zearalenone (ZEN) focus on the mycotoxin's effect on the reproductive system. Since estrogen receptors are present on various types of immunocompetent cells, ZEN can also modify diverse immune functions. This study analyzed immunocompetent cells isolated from Peyer's patches in the ileum of pigs administered ZEN in the estimated daily dose of 8 μg kg(-1) BW (equivalent of 100 μg kg(-1) feed per day(-1)). The objective of the study was to determine whether long-term exposure to low ZEN doses below the NOEL threshold leads to changes in the percentages of lymphocyte subpopulations and cytokine secretion by Th1 (IL-2, IFN-γ) and Th2 (IL-4 and IL-10) lymphocytes in Peyer's patches of the ileum after in vitro stimulation with lipopolysaccharides (LPS). Immunocompetent cells isolated from Payer's patches on experimental days 0, 14, 28 and 42 were cultured in vitro and stimulated with LPS. The presence of IL-2, IFN-γ, IL-4 and IL-10 in culture media was determined by the ELISA method. The results of the study indicate that ZEN inhibits IL-2 and IFN-γ secretion and stimulates IL-4 and IL-10 produc- tion by Th1 and Th2 lymphocytes by shifting the Th1/Th2 balance towards the humoral immune response. The above can promote allergic responses, as demonstrated by the increase in the size of B1 cell populations producing more autoantibodies. ZEN can also lower resistance to viruses and tumors by inhibiting the proliferation of NK cells and IFN-γ secretion.