Toxic effects of zearalenone and alpha-zearalenol on the regulation of steroidogenesis and testosterone production in mouse Leydig cells

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.

Enokitake Mushroom and Its Active Component, Adenosine, Which Restores Testosterone Production in Impaired and Fatigued Mouse Models

Several studies have reported the effects of the consumption of various mushroom species on the testes in animal experimental models. Mushrooms, including enokitake mushrooms (Flammulina velutipes), and vegetables contain adenosine may affect testosterone production. Here, we aimed to elucidate the effects of enokitake and its active component, adenosine, on testosterone production in primary cultures of testicular cells in vivo using mice models and in vitro. The administration of enokitake ethanolic extract increased testosterone production in the cisplatin-impaired mouse model. The direct effect of mushroom extracts on testicular cells was examined and liquid chromatography-mass spectrometry analysis confirmed that the mushroom- and vegetable-induced increase in testosterone production mainly involved adenosine. Additionally, the administration of enokitake extract or adenosine to wet floor fatigue model mice promoted testicular testosterone production and enhanced Leydig cell function through insulin-like peptide three level upregulation. Structurally related compounds, including cordycepin, showed lower bioactivity than adenosine. This study showed that the ingestion of adenosine-containing mushrooms and vegetables may effectively increase testicular testosterone production. We conclude that mushrooms with a relatively high adenosine content, such as enokitake, may be useful against aging and fatigue.

New evidence for deleterious effects of environmental contaminants on the male gamete

The decreasing trend in human and domestic animal fertility in recent decades has resulted in the question of whether reduced sperm quality is associated with changes in global climate and the environment. Proposed causes for reduced sperm quality include environmental contaminants, which enter into the body of animals through the food chain and are transported to the reproductive tract, where contaminating agents can have effects on fertilization capacities of gametes. In this review, there is a focus on various environmental contaminants and potential effects on male fertility. Human-derived contaminants, particularly endocrine-disrupting phthalates and the pesticide atrazine, are discussed. Naturally occurring toxins are also addressed, in particular mycotoxins such as aflatoxin which can be components in food consumed by humans and animals. Mechanisms by which environmental contaminants reduce male fertility are not clearly defined; however, are apparently multifactorial (i.e., direct and indirect effects) with there being diverse modes of action. Results from studies with humans, rodents and domestic animals indicate there are deleterious effects of contaminants on male gametes at various stages of spermatogenesis (i.e., in the testis) during passage through the epididymis, and in mature spermatozoa, after ejaculation and during capacitation. Considering there is never detection of a single contaminant, this review addresses synergistic or additive effects of combinations of contaminants. There is new evidence highlighted for the long-lasting effects of environmental contaminants on spermatozoa and developing embryos. Understanding the risk associated with environmental contaminants for animal reproduction may lead to new management strategies, thereby improving reproductive processes.

Effects of Intestinal Microorganisms on Metabolism and Toxicity Mitigation of Zearalenone in Broilers

Simple Summary

Zearalenone (ZEN) widely contaminates all the feed crops, and ZEN may cause harmful damage to animals and humans. Different animals have different sensitivity to ZEN. Among these animals, chickens show a strong resistance. Intestinal microorganisms are essential in digestion and degradation. Therefore, we hypothesise whether intestinal microorganisms in chickens play an important role in digesting and degrading ZEN. In this study, we found that intestinal microorganisms could degrade ZEN to a certain degree by both vivo and vitro experiments. We concluded that the intestinal microbiota of broilers had metabolic effects on ZEN and alleviated antioxidant and liver damage caused by ZEN to broilers. Moreover, we found some key bacteria that are important in degrading ZEN.

Abstract

Zearalenone (ZEN) is an estrogenic mycotoxin, and chickens are relatively insensitive to it. In this study, the effects of intestinal microorganisms on ZEN metabolism and toxicity mitigation in broilers were studied by two experiments. Firstly, in vitro, ZEN was incubated anaerobically with chyme from each part of the chicken intestine to study its intestinal microbial metabolism. Then, in vivo, we explored the effects of intestinal microbiota on ZEN by inhibiting intestinal microorganisms. Broilers were fed a control diet, 2.5 mg/kg ZEN diet, microbial inhibition diet or ‘microbial inhibition +2.5 mg/kg ZEN’ diet. In vitro, the results showed that the rates of ZEN degradation by microorganisms in the duodenum, ileum, caecum, and colon were 56%, 12%, 15%, and 17%, respectively, and the microorganisms could convert ZEN into Zearalenol (ZOL). After microbial inhibition in vivo, the content of ZEN and its metabolites in excreta of broilers increased significantly, and antioxidant damage and liver damage were aggravated. 16S rRNA sequencing results showed that antioxidant indices and the content of ZEN and its metabolites in excreta were significantly correlated with the relative abundance of Streptococcus, Lactococcus and Enterococcus, etc. In conclusion, the intestinal microorganisms of broilers play an important role in ZEN metabolism and ZEN-induced antioxidant and liver injury mitigation, among which the key bacteria include Streptococcus, Lactococcus and Enterococcus, etc.

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.

Zearalenone Induces Apoptosis and Autophagy in a Spermatogonia Cell Line

Zearalenone (ZEN), a widely known mycotoxin, is mainly produced by various Fusarium species, and it is a potent estrogenic metabolite that affects reproductive health in livestock and humans. In this study, the molecular mechanisms of toxicity and cell damage induced by ZEN in GC-1 spermatogonia (spg) cells were evaluated. Our results showed that cell viability decreased and apoptosis increased in a dose-dependent manner when GC-1 spg cells were exposed to ZEN. In addition, the key proteins involved in apoptosis, cleaved caspase-3 and -8, BAD, BAX, and phosphorylation of p53 and ERK1/2, were significantly increased in ZEN-exposed GC-1 spg cells for 24 h, and cytochrome c was released from mitochondria by ZEN. Interestingly, ZEN also triggered autophagy in GC-1 spg cells. The expression levels of the autophagy-related genes Atg5, Atg3, Beclin 1, LC3, Ulk1, Bnip 3, and p62 were significantly higher in ZEN-treated GC-1 spg cells, and the protein levels of both LC3A/B and Atg12 were remarkably increased in a dose-dependent manner in ZEN-exposed GC-1 spg cells compared to the control. In addition, immunostaining results showed that ZEN-treated groups showed a remarkable increase in LC 3A/B positive puncta as compared to the control in a dose-dependent manner based on confocal microscopy analysis in GC-1 spg cells. Our findings suggest that ZEN has toxic effects on tGC-1 spg cells and induces both apoptosis and autophagy.

Structure-toxicity relationships, toxicity mechanisms and health risk assessment of food-borne modified deoxynivalenol and zearalenone: A comprehensive review

Mycotoxin, as one of the most common pollutants in foodstuffs, poses great threat to food security and human health. Specifically, deoxynivalenol (DON) and zearalenone (ZEN)-two mycotoxin contaminants with considerable toxicity widely existing in food products-have aroused broad public concerns. Adding to this picture, modified forms of DON and ZEN, have emerged as another potential environmental and health threat, owing to their higher re-transformation rate into parent mycotoxins inducing accumulation of mycotoxin in humans and animals. Given this, a better understanding of the toxicity of modified mycotoxins is urgently needed. Moreover, the lack of toxicity data means a proper risk assessment of modified mycotoxins remains challenging. To better evaluate the toxicity of modified DON and ZEN, we have reviewed the relationship between their structures and toxicities. The toxicity mechanisms behind modified DON and ZEN have also been discussed; briefly, these involve acute, subacute, chronic, and combined toxicities. In addition, this review also addresses the global occurrence of modified DON and ZEN, and summarizes novel methods-including in silico analysis and implementation of relative potency factors-for risk assessment of modified DON and ZEN. Finally, the health risk assessment of modified DON and ZEN has also been discussed comprehensively.

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.

Male reproductive toxicity of zearalenone-meta-analysis with mechanism review

Zearalenone (ZEA) is an oestrogen-like mycotoxin produced by Fusarium fungi, which has a considerable impact on human and animal health and results in substantial economic losses worldwide. This study aimed to demonstrate the reproductive injury induced by ZEA in rodents. We conducted a rigorous meta-analysis of the related literature via PubMed, Embase, and Web of Science. The scope of the study includes the following: development of reproductive organs, serum testosterone, oestradiol, and luteinizing hormone (LH) levels; parameters of Leydig cells; and parameters of semen. In total, 19 articles were reviewed. Compared with the control group, the increased relative epididymis weight, increased serum oestradiol level, and decreased LH levels in the prenatally exposed group were observed. In pubertal and adult rodents, the relative testicular weight, serum oestradiol level, Leydig cell number, and percentage of ST (+) Leydig cells decreased under ZEA exposure. In rodents at all ages, decreased serum testosterone level, sperm concentration, sperm motility rate, and increased serum deformity rate were observed in exposed groups compared with control groups. Although subgroup analysis failed to identify a clear dose-response relationship between ZEA exposure and reproductive system damage in male rodents, we still managed to confirm that zearalenone could decrease the serum testosterone level at the dosage of 50 mg/kg*day, 1.4 mg/kg*day, and 84 mg/kg*day, of prenatal, pubertal, and mature rodents respectively; pubertal zearalenone exposure impairs the quality and quantity of sperms of rodents at the dosage of 1.4 mg/kg*day and mature zearalenone exposure has the same effect at the dosage of 84 mg/kg*day. In conclusion, we found that ZEA exposure can cause considerable damage to the reproductive system of rodents of all ages. While the exact underlying mechanism of ZEA-induced toxicity in the reproductive system remains largely unknown, the theories of oestrogen-like effects and oxidative stress damage are promising.

Comparative analysis of the detrimental in vitro effects of three fusariotoxins on the selected structural and functional characteristics of rabbit spermatozoa

In this study, we evaluated the in vitro effects of 1-50 μM zearalenone (ZEA), deoxynivalenol (DON) and T-2 toxin (T-2) on rabbit spermatozoa for as much as 8 h of in vitro exposure. Our results indicate that all sperm quality parameters were negatively affected by these fusariotoxins in a time- and dose-dependent manner. The most prominent structure affected by ZEA was the plasma membrane, exhibiting alterations consistent with the onset of apoptosis and reactive oxygen species (ROS) overproduction. This correlated with the most prominent decline of the sperm motility among all selected fusariotoxins. Significant necrotic changes and mitochondrial dysfunction were primarily responsible for the sperm damage in the presence of T-2. Finally, exposure of spermatozoa to DON led to a significant decrease in the DNA integrity. This study may provide new information on the specific mechanisms of action involved in the in vitro toxic behavior of fusariotoxins on male gametes.

The insensitive mechanism of poultry to zearalenone: A review

Zearalenone (ZEN) is one of the most common contaminating mycotoxins and is mainly produced by Fusarium graminearum. ZEN and its metabolites can interfere with estrogen function and affect animals' reproductive ability. Pigs are most susceptible to ZEN, and ZEN is less harmful to poultry than to pigs. The exact mechanism for the difference in susceptibility remains unclear. In this review, we summarized some possible reasons for the relative insensitivity of poultry to ZEN, such as the lower total amount of α-zearalenol (α-ZOL) and the α-ZOL-to-β-ZOL ratio which reduce the toxicity of ZEN to poultry. The faster hepatic and enteric circulation, and excretion capacity in poultry can excrete more ZEN and its metabolites. There are other possible factors such as the transformation of intestinal microorganisms, differences in hydroxysteroid dehydrogenases' activity, high estrogen levels, and low estrogen receptors affinity which can also cause poultry to be relatively insensitive to ZEN. In this review, we summarized the hazards, pollution status, metabolic pathways, and some measures to mitigate ZEN's harmfulness. Specifically, we discussed the possible mechanisms of low reproductive toxicity by ZEN in poultry.

Dose-Effect of Zearalenone on the Localization and Expression of Growth Hormone, Growth Hormone Receptor, and Heat Shock Protein 70 in the Ovaries of Post-weaning Gilts

Zearalenone (ZEA) has an estrogen-like effect, which can injure the reproductive system of animals, causing infertility, and abortion in sows. However, the underlying mechanisms are still not clear. The objective of this study was to assess the effects of ZEA on the localization and expression of growth hormone (GH), growth hormone receptor (GHR), and heat shock protein 70 (Hsp70) in the ovaries of post-weaning gilts. Forty healthy post-weaning gilts were randomly provided one of four diets: normal basal diet supplemented with 0 (control), 0.5 (ZEA0.5), 1.0 (ZEA1.0), and 1.5 (ZEA1.5) mg ZEA/kg. Gilts were housed and fed individually for 35 days; the ovaries were collected after euthanasia for antioxidant index, relative mRNA and protein expression, and immunohistochemical analyses of GH, GHR, and Hsp70. The results revealed that the glutathione peroxidase and total superoxide dismutase levels decreased (p < 0.05), whereas the malondialdehyde level increased (p < 0.05) with increasing ZEA content. The localization pattern of GH, GHR, and Hsp70 in ZEA-treated gilts was the same as that in the control; however, the localization of yellow and brown immunoreactive substances of GH, GHR, and Hsp70 was stronger in the ZEA groups than in the control. The relative mRNA and protein expression of GHR and Hsp70 was the highest in the ZEA1.0 group (p < 0.05), whereas that of GH was the highest in the ZEA0.5 group (p < 0.05). The mRNA and protein expression of GH was lower in the ZEA1.5 group than in the control (p < 0.05). Hsp70 results showed adverse responses to increasing ZEA levels in gilt ovaries, suggesting that Hsp70 played an important role in alleviating ZEA-induced oxidative stress.

Zearalenone perturbs the circadian clock and inhibits testosterone synthesis in mouse Leydig cells

Zearalenone (ZEA), a mycotoxin, is known to impair reproductive capability by disrupting the synthesis and secretion of testosterone by Leydig cells (LCs), although the mechanism is unknown. Robust rhythmicity of circadian clock and steroidogenic genes were identified in LCs. The aim of this study was to examine whether ZEA significantly attenuated the transcription of core clock genes (Bmal1, Dbp, Per2, and Nr1d1) as well as steroidogenic genes (StAR, Hsd3b2, and Cyp11a1) in mouse testis Leydig cell line (TM3). Western blotting confirmed declines in BMAL1, NR1D1, and StAR protein levels. ZEA also suppressed secreted testosterone levels. In primary LCs, isolated from PER2::LUCIFERASE reporter gene knock in mice, ZEA diminished the amplitude of PER2::LUC expression, and induced a phase shift and period extension. In primary LCs, ZEA also suppressed the expression levels of core clock and steroidogenic genes, reduced protein levels of BMAL1, and decreased testosterone secretion. In vivo expression of core clock and steroidogenic genes were reduced in testes of mice exposed to ZEA for 1 week leading to decreased serum testosterone levels. In summary, data suggest that ZEA may impair testosterone synthesis through attenuation of the circadian clock in LCs culminating in reproductive dysfunction in male mammals .

Bisphenol A attenuates testosterone production in Leydig cells via the inhibition of NR1D1 signaling

Bisphenol A (BPA) is an endocrine-disrupting compound that impairs testosterone synthesis in male mammals. A circadian clock gene deficiency leads to diminished fertility and even infertility in male mice. However, whether circadian clock signaling pathways mediate the suppressive effect of BPA on testosterone synthesis in Leydig cells (LCs) remains unknown. The present study aims to detect the effect of BPA on cellular circadian clock and testosterone synthesis in mouse LCs, and examine the mechanisms underlying NR1D1 signaling. BPA treatment significantly attenuated the transcription levels of Nr1d1 and steroidogenic genes (Hsd3b2 and Hsd17b3) in TM3 cells, but increased other circadian clock gene levels (Per2 and Dbp). BPA treatment also significantly downregulated NR1D1 and StAR protein expression, but upregulated BMAL1 protein expression in TM3 cells. Furthermore, there was a marked decline in testosterone production in BPA-treated TM3 cells. Intraperitoneal injection of BPA profoundly reduced NR1D1 and StAR protein levels and steroidogenic gene transcription levels (Cyp11a1, Hsd3b2, and Hsd17b3), while enhancing BMAL1 protein and other circadian clock gene (Per2 and Dbp) levels in mouse testes. Notably, serum testosterone levels were also drastically reduced in BPA-treated mice. Moreover, SR9009, an NR1D1 agonist, augmented testosterone production in TM3 cells via elevated expression of steroidogenic genes (StAR, Cyp11a1 and Hsd17b3). Conversely, Nr1d1 knockdown inhibited testosterone accumulation and attenuated steroidogenic gene expression. Moreover, treatment with SR9009 partially reversed the BPA effect on the circadian clock and testosterone production. Taken together, our study demonstrates that BPA perturbs testosterone production, at least partially, via inhibiting NR1D1 signaling in LCs.

Cyclic depsipeptide mycotoxin exposure may cause human endocrine disruption: Evidence from OECD in vitro stably transfected transcriptional activation assays

The presence of cyclic depsipeptide mycotoxins in foods and feedstuffs could potentially cause endocrine disrupting effects on humans and wildlife by their inhibition of active steroidogenesis. Therefore, we attempted to assess the human estrogen receptor (ER) and androgen receptor (AR) agonistic/antagonistic effects of representative cyclic depsipeptide mycotoxins, enniatin A1 (ENN A1), and enniatin B1 (ENN B1), by OECD Performand Based Test Guideline (PBTG) No.455, VM7Luc ER transcriptional activation (TA) assay and OECD TG No. 458, 22Rv1/MMTV_GR-KO AR TA assay. No tested cyclic depsipeptide mycotoxins were found to be ER and AR agonists in VM7Luc ER TA and 22Rv1/MMTV_GR-KO AR TA assays. On the other hand, ENN A1, and ENN B1 exhibited the ER and AR antagonistic effects with IC₃₀ and IC₅₀ values in both TA assays. These two cyclic depsipeptide mycotoxins, which were determined as ER and AR antagonists by two in vitro assays, bound to ERα, and AR. Then ENN A1, and ENN B1 inhibited the dimerization of ERα, and AR. These results, for the first time indicated that ENN A1, and ENN B1 could have potential endocrine disrupting effects mediated by interaction of ERα and AR using international standard testing methods to determine the potential endocrine disrupting chemical.

Maternal exposure to zearalenone in masculinization window affects the fetal Leydig cell development in rat male fetus

Zearalenone is a phenolic Fusarium mycotoxin, which is ubiquitous in human and animal feedstuff and often co-occurs with other mycotoxins. ZEA has been reported to disturb Leydig cell function and even cause the apoptosis to the Leydig cells. However, the effects of gestational exposure to zearalenone on fetal Leydig cells and the underlying mechanism remain unknown. Sprague Dawley dams were daily gavaged with 0, 2.5, 5, 10, and 20 mg/kg body weight ZEA from gestational day 14-21. On gestational day 21, rats were euthanized and serum testosterone levels were measured, and testes were collected for further evaluation of Leydig cell number, cell size, gene, and protein expression. Zearalenone significantly decreased anogenital distance and its index of male fetus, serum testosterone levels, Leydig cell proteins (SCARB1, STAR, CYP11A1, CYP17A1, and INSL3), and fetal Leydig cell number at 10 and/or 20 mg/kg by delaying the commitment of stem Leydig cells into the Leydig cell lineage and proliferation. Further study found that Notch signaling (RFNG, PSEN1, NOTCH1, and NOTCH3) was up-regulated by zearalenone. In conclusion, gestational exposure to high doses of zearalenone (10 and 20 mg/kg) blocks fetal Leydig cell development, thus possibly causing the anomalies of the male reproductive tract.

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.

Inhibition of progesterone biosynthesis induced by deca-brominated diphenyl ether (BDE-209) in mouse Leydig tumor cell (MLTC-1)

Polybrominated Diphenyl Ethers (PBDEs) have been extensively applied as flame retardants in different polymeric materials since the 1970s, which have become a group of long-lasting environmental pollutants. They have been reported from previous studies to accumulate and then disrupt the endocrine system in humans. However, the mechanisms are still little known. In the present study, mouse Leydig tumor cells were utilized to investigate steroidogenic activity influenced by deca-brominated diphenyl ether (BDE-209). Our data showed that BDE-209 did not change intracellular cAMP level in the presence of human Chorionic Gonadotropin (hCG), cholera toxin (CT), and forskolin, which indicated that reduction of progesterone may not be related to the hCG-cAMP signal pathway in MLTC-1 cells. Furthermore, the reduction of progesterone generation was not shifted by 8-Br-cAMP, an analog of cAMP, indicating that BDE-209 may inhibit post-cAMP sites. In addition, mRNA expression levels of P450 side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase (3β-HSD) presented a concentration-dependent decrease. In conclusion, this study suggested that BDE-209 may attenuate the progesterone secretion mainly through lowering the expression of these two enzymes.

T

Zearalenone (ZEA) is a non-steroidal estrogen mycotoxin produced by several Gibberella and Fusarium species. Accumulating evidence has indicated that ZEA strongly stimulates cell proliferation. However the detailed molecular and cellular mechanisms of ZEA-mediated induction of cell proliferation have not yet been completely explained. The aim of this study was to detect the role of miRNAs in ZEA-mediated induction of cell proliferation. The effects of ZEA on cell proliferation were assessed using a cell counting kit assay and xCELLigence system. Micro-RNA sequencing was performed after treatment of TM3 cells with ZEA (0.01 μmol/L) for different time periods (0, 2, 6 and 18 h). Cell function and pathway analysis of the miRNA target genes were performed by Ingenuity Pathway Analysis (IPA). We found that ZEA promotes TM3 cell proliferation at low concentrations. miRNA sequenceing revealed 66 differentially expressed miRNAs in ZEA-treated cells in comparison to the untreated control ( p < 0.05). The miRNA sequencing indicated that compared to control group, there were 66 miRNAs significant change (p < 0.05) in ZEA-treated groups. IPA analysis showed that the predicated miRNAs target gene involved in cell Bio-functions including cell cycle, growth and proliferation, and in signaling pathways including MAPK and RAS-RAF-MEK-ERK pathways. Results from flow cytometry and Western Blot analysis validated the predictions that ZEA can affect cell cycle, and the MAPK signaling pathway. Taking these together, the cell proliferation induced ZEA is regulated by miRNAs. The results shed light on the molecular and cellular mechanisms for the mediation of ZEA to induce proliferation.

Effects of zearalenone and its derivatives on the synthesis and secretion of mammalian sex steroid hormones: A review

Zearalenone (ZEA), a non-steroidal estrogen mycotoxin produced by several species of Fusarium fungi, can be metabolized into many other derivatives by microorganisms, plants, animals and humans. It can affect mammalian reproductive capability by impacting the synthesis and secretion of sex hormones, including testosterone, estradiol and progesterone. This review summarizes the mechanisms in which ZEA and its derivatives disturb the synthesis and secretion of sex steroid hormones. Because of its structural analogy to estrogen, ZEA and its derivatives can exert a variety of estrogen-like effects and engage in estrogen negative feedback regulation, which can result in mediating the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the pituitary gland. ZEA and its derivatives can ultimately reduce the number of Leydig cells and granulosa cells by inducing oxidative stress, endoplasmic reticulum (ER) stress, cell cycle arrest, cell apoptosis, and cell regeneration delay. Additionally, they can disrupt the mitochondrial structure and influence mitochondrial functions through overproduction of reactive oxygen species (ROS) and aberrant autophagy signaling ways. Finally, ZEA and its derivatives can disturb the expressions and activities of the related steroidogenic enzymes through cross talking between membrane and nuclear estrogen receptors.

Mycotoxin zearalenone induced gonadal impairment and altered gene expression in the hypothalamic-pituitary-gonadal axis of adult female zebrafish (Danio rerio)

In the present study, we aimed to assess the adverse effects of zearalenone (ZEA) at environmentally relevant concentrations (0.5, 1, 5 and 10 μg l^-1 ) on hypothalamic-pituitary-gonadal axis associated reproductive function using zebrafish model. ZEA was exposed to female zebrafish for 21 days to assess growth indices such as condition factor, hepatosomatic index, gonadosomatic index and caspase 3 activity. Further, expression of estrogen receptor (ER) α and CYP19a1b genes in the brain, ERα and vitellogenin (Vtg) genes in the liver and follicle-stimulating hormone receptor, luteinizing hormone receptor, ERα, steroidogenic acute regulatory protein, 3β-hydroxysteroid dehydrogenase (HSD), 17-βHSD and CYP19a1 genes in the ovary were also investigated. Our results showed that there were no significant changes in the condition factor and hepatosomatic index, whereas a significant (P < .05) reduction in the gonadosomatic index, increase in caspase 3 activities and Vtg expression was observed at higher concentration. However, no significant changes were observed at lower treatment levels. Further, we also observed significant (P < .05) upregulation in ERα, Vtg, luteinizing hormone receptor, steroidogenic acute regulatory protein, 3β-HSD, 17β-HSD, CYP19a1 and CYP19a1b genes in treatment groups with higher levels of ZEA. Moreover, in histopathological examination, we observed oocyte atresia and oocyte membrane detachment in ovaries at the highest concentration. In conclusion, the present study revealed the negative impact of ZEA on zebrafish reproductive system by involvement of the hypothalamic-pituitary-gonadal axis-associated reproductive function.

Zearalenone and alpha-zearalenol inhibit the synthesis and secretion of pig follicle stimulating hormone via the non-classical estrogen membrane receptor GPR30

Zearalenone (ZEA) is one of the most popular endocrine-disrupting chemicals and is mainly produced by fungi of the genus Fusarium. The excessive intake of ZEA severely disrupts human and animal fertility by affecting the reproductive axis. However, most studies on the effects of ZEA and its metabolite α-zearalenol (α-ZOL) on reproductive systems have focused on gonads. Few studies have investigated the endocrine-disrupting effects of ZEA and α-ZOL on pituitary gonadotropins, including follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The present study was designed to investigate the effects of ZEA and α-ZOL on the synthesis and secretion of FSH and LH and related mechanisms in female pig pituitary. Our in vivo and in vitro results demonstrated that ZEA significantly inhibited the synthesis and secretion of FSH in the pig pituitary gland, but ZEA and α-ZOL had no effects on LH. Our study also showed that ZEA and α-ZOL decreased FSH synthesis and secretion through non-classical estrogen membrane receptor GPR30, which subsequently induced protein kinase cascades and the phosphorylation of PKC, ERK and p38MAPK signaling pathways in pig pituitary cells. Furthermore, our study showed that the LIM homeodomain transcription factor LHX3 was involved in the mechanisms of ZEA and α-ZOL actions on gonadotropes in the female pig pituitary. These findings elucidate the mechanisms behind the physiological alterations resulting from endocrine-disrupting chemicals and further show that the proposed key molecules of the α-ZOL signaling pathway could be potential pharmacological targets.

Characterization of semen quality, testicular marker enzyme activities and gene expression changes in the blood testis barrier of Kunming mice following acute exposure to zearalenone

A total of 95 8-week-old male Kunming mice were randomly assigned into five groups and exposed to zearalenone (ZEA) at doses of 25, 50, and 75 mg/kg delivered by intra-peritoneal (i.p.) injection for 5 days. The testis and epididymis indices involving sperm quality and morphology, testis enzyme activities, serum concentrations of testosterone and estrogen, and the expression levels of the three gene and protein of N-cadherin, vimentin, and claudin 11 related to the blood testis barrier (BTB) were analyzed. Results showed that ZEA significantly decreased body weight and semen quality compared to the control group along with increased activity of alkaline phosphatase (ALP), acid phosphatase (ACP), lactate dehydrogenase (LDH), and reduced serum concentrations of testosterone and estrogen. At the mRNA and protein levels, expression of N-cadherin, vimentin, and claudin 11 significantly increased; however, the mRNA and protein of N-cad expression decreased. These data suggest acute exposure to ZEA reduces sperm quality and significantly decreases the concentration of serum testosterone and estradiol. In addition, the activities of the testis marker enzymes and associated mRNA and protein expressions of the BTB were also significantly affected. Our results demonstrated that ZEA has a significant impact on the reproductive parameters of male mice which showed compensatory response to strengthen the barrier function of the BTB following ZEA exposure.

Effects of zearalenone on the localization and expression of the growth hormone receptor gene in the uteri of post-weaning piglets

OBJECTIVE

In this study, we investigated the adverse effects of dietary zearalenone (ZEA) (0.5 to 1.5 mg/kg diet) on the localization and expression of the growth hormone receptor (GHR) in the uteri of post-weaning gilts and explored alternative mechanism of the reproductive toxicity of ZEA on piglets.

METHODS

A total of forty healthy piglets (Duroc×Landrace×Large White) aged 28 d were selected for study. Piglets were transferred to single cages after 10 days' adaptation on an obstetric table. The animals were allocated to one of four treatments: a normal 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 after the 10-d adaptation. Analyzed ZEA concentrations in the diets were 0, 0.52±0.07, 1.04±0.03, and 1.51±0.13 mg/kg, respectively. At the end of the feeding trial, piglets were euthanized after being fasted for 12 h. Two samples of uterine tissue from each pig were rapidly collected, one of which was stored at -80°C for analysis of the relative mRNA and protein expression of GHR, and the second was promptly fixed in Bouin's solution for immunohistochemical analysis.

RESULTS

The relative weight of the uteri and thickness of the myometrium and endometrium increased linearly (p<0.001) and quadratically (p<0.001) with an increasing level of ZEA. The results of immunohistochemical analysis indicated that GHR immunoreactive substance was mainly localizated in the cytoplasm of uterine smooth muscle, glandular epithelial, luminal epithelial, stromal, and vascular endothelial cells. In contrast, nuclear staining was rarely observed. The immunoreactive integrated optic density of GHR in the myometrium, luminal epithelium, glandular epithelium, and whole uteri of weaning gilts increased linearly (p<0.001) and quadratically (p<0.05) with an increasing level of ZEA. The mRNA and protein expression of GHR in the uteri of weaning gilts increased linearly (p<0.001) and quadratically (p<0.05) with an increasing level of ZEA.

CONCLUSION

In conclusion, ZEA at a concentration of 0.5 mg/kg was sufficient to significantly thicken the myometrium and endometrium, and at a concentration of 1.0 mg/kg induced a high level of GHR expression to promote growth and development of the uteri. This revealed an alternative molecular mechanism whereby ZEA induces growth and development of the uteri and provides a theoretical basis for the revision of Chinese feed hygiene standards.

Circadian clock and steroidogenic-related gene expression profiles in mouse Leydig cells following dexamethasone stimulation

Previous studies have shown that circadian clock genes are expressed in mammalian testes; however, it remains unclear if the expression patterns of these genes are cyclic. Furthermore, it is unknown whether Leydig cells, the primary androgen secreting cells in the testis, play a role in the rhythmicity of circadian clock and steroidogenic-related gene transcription. Here, we examine the circadian clock of mouse Leydig cells, and the link to steroidogenic-related gene transcription. We confirm, via sampling over a full circadian time (CT) period, a lack of circadian rhythmicity in mouse testes in comparison with the robust gene expression cycling of circadian clock genes in mouse livers. Immunofluorescence imaging of mouse testes collected at CT0 and CT12 show that the BMAL1 protein is exclusively expressed in mouse Leydig cells, and clearly linked to the circadian oscillation. Furthermore, dexamethasone treatment synchronized the expression of several of these canonical circadian clock and steroidogenic-related genes. Bioinformatic analyses revealed the presence of several circadian clock-related sequence motifs in the promoters of these steroidogenic-related genes. Our results suggest mouse Leydig cells may contain a functional circadian oscillator and the circadian clockwork in mouse Leydig cells regulates steroidogenic-related gene transcription by binding to the E-box, RORE, and D-box motifs in their promoters. However, additional research is required to determine the specific molecular mechanisms involved.

The Protective Effect of Selenium on Chronic Zearalenone-Induced Reproductive System Damage in Male Mice

This study aims to explore the protective effect of selenium (Se) on chronic zearalenone (ZEN)-induced reproductive system damage in male mice and the possible protective molecular mechanism against this. The chronic ZEN-induced injury mouse model was established with the continuous intragastric administration of 40 mg/kg body mass (B.M.) ZEN for 28 days. Then, interventions with different doses (0.1, 0.2, and 0.4 mg/kg B.M.) of Se were conducted on mice to analyse the changes in organ indexes of epididymis and testis, antioxidant capability of testis, serum level of testosterone, sperm concentration and motility parameters, and the expression levels of apoptosis-associated genes and blood testis barrier- (BTB) related genes. Our results showed that Se could greatly improve the ZEN-induced decrease of epididymis indexes and testis indexes. Results also showed that the decrease in sperm concentration, sperm normality rate, and sperm motility parameters, including percentage of motile sperm (motile), tropism percentage (progressive) and sperm average path velocity (VAP), caused by ZEN were elevated upon administration of the higher dose (0.4 mg/kg) and intermediate dose (0.2 mg/kg) of Se. Selenium also significantly reduced the content of malondialdehyde (MDA) but enhanced the activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the testis tissue. Further research demonstrated that ZEN increased the level of mRNA expression of BCL2-associated X protein (Bax) and caspase 3 (Casp3), decreased the level of mRNA expression of B cell leukemia/lymphoma 2 (Bcl2), vimentin (Vim) and cadherin 2 (Cdh2), whereas the co-administration of Se reversed these gene expression levels. Our results indicated that high levels of Se could protect against reproductive system damage in male mice caused by ZEN and the mechanism might such be that Se improved mice antioxidant ability, inhibited reproductive cell apoptosis, and increased the decrease of BTB integrity-related genes caused by ZEN.

Effects of TBEP on the induction of oxidative stress and endocrine disruption in Tm3 Leydig cells

The flame retardant tris (2-butoxyethyl) phosphate (TBEP) is a frequently detected contaminant in the environment. In the cultured TM3 cells (originated from ATCC), effects of TBEP on the induction of oxidative stress and endocrine disruption were evaluated. It was observed that exposure to 100 μg/mL TBEP for 24 h significantly reduced the viability of TM3 cells. The mRNA levels of genes related to oxidative stress including Sod, Gpx1, Cat, and Gsta1 were changed in a dose-dependent and/or time-dependent manner after exposure to 30 and 100 μg/mL TBEP for 6, 12, or 24 h. Moreover, notable decrease in glutathione (GSH) contents and increases in oxidized glutathione (GSSG) contents as well as the antioxidant enzyme activities like superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase were found in the group treated with 100 μg/mL TBEP for 24 h, indicating that TBEP induced oxidative stress in TM3 Leydig cells. In addition, the expression of genes related to testosterone (T) synthesis including cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), cytochrome P450 17α-hydroxysteroid dehydrogenase (P450-17α), and 17β-hydroxysteroid dehydrogenase (17β-HSD) and T levels in medium were remarkably declined by the treatment of 100 μg/mL TBEP for 24 h. And TBEP could inhibit the expression of P450-17α and 17β-HSD and T levels up-regulated by hCG in TM3 cells. Taken together, these findings indicated that TBEP can induce oxidative stress and alter steroidogenesis in TM3 cells. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1276-1286, 2016.

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.

Xenoestrogens diethylstilbestrol and zearalenone negatively influence pubertal rat's testis

The aim of this study was to assess the impact of xenoestrogens: diethylstilbestrol (DES) and zearalenone (ZEA) on rat's pubertal testis and to compare it with the effect of natural estrogen - 17beta-estradiol (E). Male Wistar rats were daily, subcutaneously injected at 5th-15th postnatal days (p.d.) with E (1.25 or 12.5 mug) or DES (1.25 or 12.5 mug) or ZEA (4 or 40 mug) or vehicle. At 16th p.d. testes were dissected, weighted, and paraffin embedded. Following parameters were assessed: diameter and length of seminiferous tubule, numbers of spermatogonia A+intermediate+B (A/In/B), preleptotene spermatocytes (PL), leptotene+zygotene+pachytene spermatocytes (L/Z/PA) and Sertoli cells per testis. Testes weight, seminiferous tubule diameter and length were decreased by both doses of E, DES and ZEA. DES effect was the strongest, but its influence on testis weight and seminiferous tubule length, on the contrary to E and ZEA, was not dose-dependent. Similarly, DES in both doses had the most severe negative impact on the number of germ and Sertoli cells. The negative influence of E on germ cells was less pronounced. The negative effect of ZEA was seen only after administration of the higher dose on spermatogonia number, while DES and E decreased A/In/B number more evidently. Sertoli cell number were decreased after both doses of E. ZEA40 decreased Sertoli cell number while ZEA4 had no effect.

CONCLUSION

exposure of prepubertal male rat to DES has the strongest detrimental effect on the developing testis in comparison to E and ZEA. Both, E and DES, decreased number of germ and Sertoli cells, diminished seminiferous tubule diameter, length and testis weight. ZEA had much more weaker effect than the potent estrogens.

TPP and TCEP induce oxidative stress and alter steroidogenesis in TM3 Leydig cells

Effects of triphenyl phosphate (TPP) and tris-(2-chloroethyl) phosphate (TCEP) exposure on induction of oxidative stress and endocrine disruption were investigated in TM3 cells. After 24h exposure, cell growth declined and morphology changed in TPP and TCEP treated groups with high dosages. Significant increases in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione S-transferase (GST) activities and their respective gene expressions in a dose-dependent and/or time-dependent manner in TPP or TCEP groups. Moreover, the expression of main genes related to testosterone (T) synthesis including cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), cytochrome P450 17α-hydroxysteroid dehydrogenase (P450-17α), 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-hydroxysteroid dehydrogenase (17β-HSD) were dramatically reduced by TPP and TCEP treatments, especially with the high dosage for 24h. TPP and TCEP treatments for 24h caused significant decreases in T levels in the medium. Furthermore, co-treatments of hCG with TPP or TCEP could inhibit hCG-induced changes in the expression of P450scc, P450-17α and 17β-HSD and T levels. Taken together, TPP and TCEP could induce oxidative stress and endocrine disruption in TM3 cells.

Mycotoxin zearalenone induces apoptosis in mouse Leydig cells via an endoplasmic reticulum stress-dependent signalling pathway

Zearalenone (ZEN) is a Fusarium mycotoxin that causes several reproductive disorders and genotoxic effects. This study demonstrated the involvement of endoplasmic reticulum (ER) stress in ZEN-induced mouse Leydig cell death. Our study showed that ZEN reduced cell proliferation in a murine Leydig tumour cell line in a dose-dependent manner. The involvement of apoptosis as a major cause of ZEN-induced cell death was further confirmed by the results of a caspase-3 activity assay, which showed a ZEN dose-dependent increase in cell death. Treatment of MLTC-1 and primary mouse Leydig cells with ZEN upregulated the expression of the ER stress-typical markers GRP78, CHOP and caspase-12 protein. Further, pre-treating the cells with 4-phenylbutyrate or knocking down GRP78 using lentivirus-encoded shRNA significantly diminished ZEN-induced apoptosis and inhibited the expression of CHOP and caspase-12. In summary, these results suggest that the activation of an ER stress pathway plays a key role in ZEN-induced apoptosis in the mouse Leydig cells.

Zearalenone Altered the Serum Hormones, Morphologic and Apoptotic Measurements of Genital Organs in Post-weaning Gilts

The present study was aimed at investigating the adverse effects of dietary zearalenone (ZEA) (1.1 to 3.2 mg/kg diet) on serum hormones, morphologic and apoptotic measurements of genital organs in post-weaning gilts. A total of twenty gilts (Landrace×Yorkshire×Duroc) weaned at 21 d with an average body weight of 10.36±1.21 kg were used in the study. Gilts were fed a basal diet with an addition of 0, 1.1, 2.0, or 3.2 mg/kg purified ZEA for 18 d ad libitum. Results showed that 3.2 mg/kg ZEA challenged gilts decreased (p<0.05) the serum levels of luteinizing hormone, however, serum levels of prolactin in gilts fed the diet containing 2.0 mg/kg ZEA or more were increased (p<0.05) compared to those in the control. Linear effects on all tested serum hormones except progesterone were observed as dietary ZEA levels increased (p<0.05). Gilts fed ZEA-contaminated diet showed increase (p<0.05) in genital organs size, hyperplasia of submucosal smooth muscles in the corpus uteri in a dose-dependent manner. However, the decreased numbers of follicles in the cortex and apoptotic cells in the ovarian were observed in gilts treated with ZEA in a dose-dependent manner. Degeneration and structural abnormalities of genital organs tissues were also observed in the gilts fed diet containing 1.1 mg/kg ZEA or more. Results suggested that dietary ZEA at 1.1 to 3.2 mg/kg can induce endocrine disturbance and damage genital organs in post-weaning gilts.

Natural Occurrence of Mycotoxins in Food and Feed: Pakistan Perspective

Fungi are commonly present in the environment and can grow under favorable conditions on an extensive variety of substrates. During harvesting, handling, storage, and distribution, agricultural commodities are subjected to infection by toxigenic molds, which may cause spoilage and produce toxic metabolites called mycotoxins. Fungal contamination of various food commodities with consequent exposure of the community to mycotoxins is a hazard that may exist depending on environmental factors, crop health, and soil conditions. Mycotoxins represent serious consequences due to substantial economic loss and risk to health. The environmental conditions of Pakistan with its mostly warm temperature are conducive to growth of toxigenic fungi resulting in mycotoxin production in different food items. Moreover, the poor conditions of storage and deficiency in regulatory measures in food quality control worsen the situation in the country. This review encompasses mycotoxin contamination of food and feed in Pakistan. High concentrations of mycotoxins are found in some commodities that are used on a daily basis in Pakistan, which may be a concern depending on dietary variety and health conditions of individuals in the population. Therefore, the mycotoxin contamination of foodstuff with exceeding levels represents a serious health hazard for the local population. There is a need to conduct more studies to analyze mycotoxin occurrence in all types of food commodities throughout the country. For consumer safety and the country's economy, the regulatory authorities should take into account this issue of contamination, and control strategies should be implemented and the quality control system of food improved.

Natural occurrence of mycotoxins in medicinal plants: a review

Medicinal plants are widely used as home remedies and raw materials for the pharmaceutical industries. Herbal remedies are used in the prevention, treatment and cure of disorders and diseases since ancient times. However, use of medicinal herbs may not meet the requirements of quality, safety and efficacy. During harvesting, handling, storage and distribution, medicinal plants are subjected to contamination by various fungi, which may be responsible for spoilage and production of mycotoxins. The increasing consumption of medicinal plants has made their use a public health problem due to the lack of effective surveillance of the use, efficacy, toxicity and quality of these natural products. The increase in use of medicinal plants may lead to an increase in the intake of mycotoxins therefore contamination of medicinal plants with mycotoxins can contribute to adverse human health problems and therefore represents a special hazard. Numerous natural occurrences of mycotoxins in medicinal plants and traditional herbal medicines have been reported from various countries including Spain, China, Germany, India, Turkey and from Middle East as well. This review discusses the important mycotoxins and their natural occurrences in medicinal plants and their products.

Zearalenone inhibits testosterone biosynthesis in mouse Leydig cells via the crosstalk of estrogen receptor signaling and orphan nuclear receptor Nur77 expression

Zearalenone (ZEA) directly inhibits testosterone biosynthesis in Leydig cells, although the mechanisms involved remains unclear. Various experiments were performed to elucidate the molecular pathway of ZEA-mediated androgen inhibition. Leydig cells were isolated from 6 week-old male ICR mice and subjected to ZEA pre-treatment. The levels of testosterone and a series of influncing factors were measured. The results showed that ZEA caused a concentration- and time-dependent inhibition of testosterone stimulated both by hCG and cAMP (P<0.05). Exposure to ZEA did not affect the LHR binding activity nor the protein expression (P>0.05). However, ZEA exposure significantly elevated the cellular cAMP levels (P<0.05) in low concentrations (5 μg/ml) or for long time periods (24 h), significantly reduce the mitochondrial membrane potential (P<0.05). The expression of P450scc, 17β-HSD, and P450c17 at the mRNA level were significantly decreased (P<0.05). The steroidogenic acute regulatory (StAR) and 3β-HSD expression was significantly increased (P<0.05). Furthermore, the ERα protein expression was not affected by ZEA, but Nur77 expression was significantly inhibited (P<0.05). These observations imply that ZEA activity interferes with testosterone biosynthesis in mouse Leydig cells via the crosstalk of estrogen receptor signaling and Nur77 expression.

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

We tested the effect of two different concentrations (150μg/l and 0.15μg/l) of mycotoxin zearalenone (ZEA) on the reproductive parameters and expression of testicular genes in male mice. In adult males, no reduction of body or reproductive organ weight was observed, and the seminiferous tubules were morphologically normal with ongoing spermatogenesis. However, we found decreased sperm concentration, increase of morphologically abnormal spermatozoa and increased binding of apoptotic marker annexin V. This study was also focused on the evaluation of gene expression profiles of 28 genes playing important roles during the processes occurring in the testicular tissue. We detected changes in the expression of genes important for proper spermatogenesis. Surprisingly, we observed a stronger effect after exposure to the lower dose of ZEA.

Analysis of zearalenone and α-zearalenol in 100 foods and medicinal plants determined by HPLC-FLD and positive confirmation by LC-MS-MS

BACKGROUND

Mycotoxins, which may contaminate many foods and medicinal plants, are poisonous to humans. A high-performance liquid chromatography with fluorescence detection (HPLC-FLD) method was successfully developed for analysing the contamination levels of zearalenone (ZON) and its metabolite α-zearalenol (α-ZOL) in 100 widely consumed foods and medicinal plants in China. Samples were extracted with methanol-water (80:20, v/v), and cleaned up by using an immunoaffinity column.

RESULTS

The limits of detection of this developed method for ZON and α-ZOL were 4 µg kg(-1) and 2.5 µg kg(-1) , respectively. Recoveries for the samples spiked with three levels (30, 60 and 300 µg kg(-1) for ZON and α-ZOL) ranged from 85.8% to 96.1% with relative standard deviation (RSD) of 2.6-7.1% for ZON, and from 89.9% to 98.7% with RSD of 1.9-9.2% for α-ZOL. Twelve (12%) of these tested samples were contaminated with ZON at levels ranging from 5.3 to 295.8 µg kg(-1). The most contaminated samples were Semen coicis, four of them in a concentration level exceeding 60 µg kg(-1) 'maximum level' (range 68.9-119.6 µg kg(-1)). Positive samples were further confirmed by liquid chromatography-tandem mass spectrometry.

CONCLUSION

The results suggest that it is necessary to control ZON contamination in medicinal plants, especially Semen coicis. This is a successful study on the analysis of ZON and α-ZOL in medicinal plants in China by HPLC-FLD. Immunoaffinity clean-up and HPLC-FLD proved to have broad applicability in the field of simultaneously detecting ZON and α-ZOL in foods and medicinal plants and other complicated matrices.