Influence of mycotoxin zearalenone and its derivatives (alpha and beta zearalenol) on apoptosis and proliferation of cultured granulosa cells from equine ovaries

FOXO3a/PI3K/Akt pathway participates in the ROS- induced apoptosis triggered by α-ZEL and β-ZEL

Zearalenone (ZEN), an estrogenic mycotoxin, is one of the most common food and feed contaminants. Also, its metabolites α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL) are considered to induce oxidative stress, however its effect in prostate cells is not known yet. Our previous observations showed that forehead box transcription factor 3a (FOXO3a) expression is modified in hormone- sensitive cells in the response to mycotoxins, similar to the phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) pathway. Thus, this study evaluated the direct molecular effect of α-ZEL and β-ZEL in a dose of 30 µM in hormone-dependent human prostate cancer (PCa) cells with the focus of the involvement of FOXO3a and PI3K/Akt signaling pathway in that effect. We observed that both active metabolites of ZEN reduced cell viability, induced oxidative stress, cell cycle arrest and apoptosis in PCa cells. Furthermore, we observed that FOXO3a as well as PI3K/Akt signaling pathway participate in ZELs induced toxicity in PCa cells, indicating that this signaling pathway might be a regulator of mycotoxin-induced toxicity generally.

First Results on the Presence of Mycotoxins in the Liver of Pregnant Fallow Deer (Dama dama) Hinds and Fetuses

Reproductive abnormalities have been observed in fallow deer populations in Hungary. We supposed mycotoxin contamination to be one of the possible causes because multi-mycotoxin contamination is known to be dangerous even at low toxin levels, especially for young animals. We investigated the spatial pattern of mycotoxin occurrences and the relationship between maternal and fetal mycotoxin levels. A total of 72 fallow deer embryos and their mothers were sampled in seven forested regions in Hungary in the 2020/2021 hunting season. We analyzed Aflatoxin (AF), Zearalenone (ZEA), Fumonizin B1 (FB1), DON, and T2-toxin concentrations in maternal and fetal livers by ELISA. AF was present in 70% and 82%, ZEA in 41% and 96%, DON in 90% and 98%, T2-toxin in 96% and 85%, and FB1 in 84% and 3% of hind and fetus livers, respectively. All mycotoxins passed into the fetus, but only Fumonizin B1 rarely passed. The individual variability of mycotoxin levels was extremely high, but the spatial differences were moderate. We could not prove a relation between the maternal and fetal mycotoxin concentrations, but we found an accumulation of ZEA and DON in the fetuses. These results reflect the possible threats of mycotoxins to the population dynamics and reproduction of wild fallow deer.

Phenotypic, endocrinological, and metabolic effects of zearalenone exposure and additive effect of heat stress in prepubertal female pigs

Independently, both heat stress (HS) and zearalenone (ZEN) compromise female reproduction, thus the hypothesis that ZEN would affect phenotypic, endocrine, and metabolic parameters in pigs with a synergistic and/or additive impact of HS was investigated. Prepubertal gilts (n = 6-7) were assigned to: thermoneutral (TN) vehicle control (TC; n = 6); TN ZEN (40 μg/kg; TZ; n = 6); pair-fed (PF; n = 6) vehicle control (PC; n = 6); PF ZEN (40 μg/kg; PZ; n = 6); HS vehicle control (HC; n = 7); and HS ZEN (40 μg/kg; HZ; n = 7) and experienced either constant 21.0 ± 0.10 °C (TN and PF) or 35.0 ± 0.2 °C (12 h) and 32.2 ± 0.1 °C (12 h) to induce HS for 7 d. Elevated rectal temperature (P < 0.01) and respiration rate (P < 0.01) confirmed induction of HS. Rectal temperature was decreased (P = 0.03) by ZEN. Heat stress decreased (P < 0.01) feed intake, body weight, and average daily gain, with absence of a ZEN effect (P > 0.22). White blood cells, hematocrit, and lymphocytes decreased (P < 0.04) with HS. Prolactin increased (P < 0.01) in PC and PZ and increased in HZ females (P < 0.01). 17β-estradiol reduced (P < 0.01) in HC and increased in TZ females (P = 0.03). Serum metabolites were altered by both HS and ZEN. Neither HS nor ZEN impacted ovary weight, uterus weight, teat size or vulva area in TN and PF treatments, although ZEN increased vulva area (P = 0.02) in HS females. Thus, ZEN and HS, independently and additively, altered blood composition, impacted the serum endocrine and metabolic profile and increased vulva size in prepubertal females, potentially contributing to infertility.

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.

Zearalenone Biodegradation by the Lactobacillus Spp. and Bacillus Spp. In Vitro

In this study, the biodegradation of zearalenone (ZEN) by cell suspensions of various Lactobacillus species (Lb. fermentum 2I3 (L1), Lb. reuteri L26 (L3), Lb. plantarum L81 (L4), Lb. reuteri 2/6 (L5), Lb. plantarum CCM 1904 (L6)), Bacillus subtilis CCM 2794 (Bs), and Bacillus licheniformis CCM 2206 (Bl); was investigated in vitro. All lactobacilli cell suspensions showed very good degradation efficiency (57.9—100 %) for zearalenone at the concentration 0.01 ppm. At higher concentrations of zearalenone, their biodegradation activity decreased significantly (0—13.9 %). Bacillus subtilis CCM 2794 was able to degrade zearalenone at concentrations of: 0.01 ppm (100 %), 0.1 ppm (74.5 %), and at higher concentrations of ZEN (1 ppm; 10 ppm), the degradation was 11.7 % and 0 %, respectively. For Bacillus licheniformis CCM 2206, no biodegradation of zearalenone was observed at the concentration of 10 ppm, but slight degradation (4.5—8.8 %) was found at lower zearalenone concentrations.

Practical Application of Urinary Zearalenone Monitoring System for Feed Hygiene Management of a Japanese Black Cattle Breeding Herd—The Relationship between Monthly Anti-Müllerian Hormone and Serum Amyloid A Concentrations

This study addresses an advantageous application of a urinary zearalenone (ZEN) monitoring system not only for surveillance of ZEN exposure at the production site of breeding cows but also for follow-up monitoring after improvement of feeds provided to the herd. As biomarkers of effect, serum levels of the anti-Müllerian hormone (AMH) and serum amyloid A (SAA) concentrations were used. Based on the results of urinary ZEN measurement, two cows from one herd had urinary ZEN concentrations which were two orders of magnitude higher (ZEN: 1.34 mg/kg, sterigmatocystin (STC): 0.08 mg/kg in roughages) than the levels of all cows from three other herds (ZEN: not detected, STC: not detected in roughages). For the follow-up monitoring of the herd with positive ZEN and STC exposure, urine, blood, and roughage samples were collected from five cows monthly for one year. A monitoring series in the breeding cattle herd indicated that feed concentrations were not necessarily reflected in urinary concentrations; urinary monitoring assay by ELISA may be a simple and accurate method that reflects the exposure/absorption of ZEN. Additionally, although the ZEN exposure level appeared not to be critical compared with the Japanese ZEN limitation in dietary feeds, a negative regression trend between the ZEN and AMH concentrations was observed, indicating that only at extremely universal mycotoxin exposure levels, ZEN exposure may affect the number of antral follicles in cattle. A negative regression trend between the ZEN and SAA concentrations could also be demonstrated, possibly indicating the innate immune suppression caused by low-level chronic ZEN exposure. Finally, significant differences (p = 0.0487) in calving intervals between pre-ZEN monitoring (mean ± SEM: 439.0 ± 41.2) and post-ZEN monitoring (349.9 ± 6.9) periods were observed in the monitored five cows. These preliminary results indicate that the urinary ZEN monitoring system may be a useful practical tool not only for detecting contaminated herds under field conditions but also provides an initial look at the effects of long-term chronic ZEN/STC (or other co-existing mycotoxins) exposure on herd productivity and fertility.

Deoxynivalenol and Zearalenone: Different Mycotoxins with Different Toxic Effects in the Sertoli Cells of Equus asinus

(1) Background: Deoxynivalenol (DON) and zearalenone (ZEA) are type B trichothecene mycotoxins that exert serious toxic effects on the reproduction of domestic animals. However, there is little information about the toxicity of mycotoxins on testis development in Equus asinus. This study investigated the biological effects of DON and ZEA exposure on Sertoli cells (SCs) of Equus asinus; (2) Methods: We administered 10 μM and 30 μM DON and ZEA to cells cultured in vitro; (3) Results: The results showed that 10 μM DON exposure remarkably changed pyroptosis-associated genes and that 30 μM ZEA exposure changed inflammation-associated genes in SCs. The mRNA expression of cancer-promoting genes was remarkably upregulated in the cells exposed to DON or 30 μM ZEA; in particular, DON and ZEA remarkably disturbed the expression of androgen and oestrogen secretion-related genes. Furthermore, quantitative RT-PCR, Western blot, and immunofluorescence analyses verified the different expression patterns of related genes in DON- and ZEA-exposed SCs; (4) Conclusions: Collectively, these results illustrated the impact of exposure to different toxins and concrete toxicity on the mRNA expression of SCs from Equus asinus in vitro.

Inflammatory cytokines as key players of apoptosis induced by environmental estrogens in the ovary

Natural and synthetic environmental estrogens (EEs), interfering with the physiological functions of the body's estrogens, are widespread and are rising much concern for their possible deleterious effects on human and animal health, in particular on reproduction. In fact, increasing evidence indicate that EEs can be responsible for a variety of disfunctions of the reproductive system especially in females such as premature ovarian insufficiency (POI). Because of their great structural diversity, the modes of action of EEs are controversial. One important way through which EEs exert their effects on reproduction is the induction of apoptosis in the ovary. In general, EEs can exert pro-and anti-apoptotic effects by agonizing or antagonizing numerous estrogen-dependent signaling pathways. In the present work, results concerning apoptotic pathways and diseases induced by representative EEs (such as zearalenone, bisphenol A and di-2-ethylhexyl phthalate), in ovaries throughout development are presented into an integrated network. By reviewing and elaborating these studies, we propose inflammatory factors, centered on the production of tumor necrosis factor (TNF), as a major cause of the induction of apoptosis by EEs in the mammalian ovary. As a consequence, potential strategies to prevent such EE effect are suggested.

Impact of Fusarium-Derived Mycoestrogens on Female Reproduction: A Systematic Review

Contamination of the world’s food supply and animal feed with mycotoxins is a growing concern as global temperatures rise and promote the growth of fungus. Zearalenone (ZEN), an estrogenic mycotoxin produced by Fusarium fungi, is a common contaminant of cereal grains and has also been detected at lower levels in meat, milk, and spices. ZEN’s synthetic derivative, zeranol, is used as a growth promoter in United States (US) and Canadian beef production. Experimental research suggests that ZEN and zeranol disrupt the endocrine and reproductive systems, leading to infertility, polycystic ovarian syndrome-like phenotypes, pregnancy loss, and low birth weight. With widespread human dietary exposure and growing experimental evidence of endocrine-disrupting properties, a comprehensive review of the impact of ZEN, zeranol, and their metabolites on the female reproductive system is warranted. The objective of this systematic review was to summarize the in vitro, in vivo, and epidemiological literature and evaluate the potential impact of ZEN, zeranol, and their metabolites (commonly referred to as mycoestrogens) on female reproductive outcomes. We conducted a systematic review (PROSPERO registration CRD42020166469) of the literature (2000–2020) following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The data sources were primary literature published in English obtained from searching PubMed, Web of Science, and Scopus. The ToxR tool was applied to assess risk of bias. In vitro and in vivo studies (n = 104) were identified and, overall, evidence consistently supported adverse effects of mycoestrogens on physiological processes, organs, and tissues associated with female reproduction. In non-pregnant animals, mycoestrogens alter follicular profiles in the ovary, disrupt estrus cycling, and increase myometrium thickness. Furthermore, during pregnancy, mycoestrogen exposure contributes to placental hemorrhage, stillbirth, and impaired fetal growth. No epidemiological studies fitting the inclusion criteria were identified.

Zearalenone and Its Metabolites-General Overview, Occurrence, and Toxicity

Mycotoxins are secondary metabolites of filamentous fungi and represent one of the most common groups of food contaminants with low molecular weight. These toxins are considered common and can affect the food chain at various stages of production, harvesting, storage and processing. Zearalenone is one of over 400 detected mycotoxins and produced by fungi of the genus Fusarium; it mainly has estrogenic effects on various organisms. Contaminated products can lead to huge economic losses and pose risks to animals and humans. In this review, we systemize information on zearalenone and its major metabolites.

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.

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.

Zearalenone: A Mycotoxin With Different Toxic Effect in Domestic and Laboratory Animals' Granulosa Cells

Zearalenone (ZEA), one of the most prevalent estrogenic mycotoxins, is mainly produced by Fusarium fungi and has been proven to affect the reproductive capacity of animals. Exposure of farm animals to ZEA is a global public health concern because of its toxicity and wide distribution in animal feeds. In vitro and in vivo experiments indicate that ZEA possesses estrogenic activity in mice, swine, Equus asinus and cattle. The precise mechanism of the reproductive toxicity of ZEA has not been established yet. This article reviews evidence on the deleterious effects of ZEA on mammalian folliculogenesis from early to final oogenesis stages. Such effects include impaired granulosa cell (GC) development and follicle steroidogenesis, reduced oocyte nest breakdown, damaged meiotic progression, poor fetal oocyte survival, accelerated primordial follicle activation and enhanced follicle atresia. These phenomena may result in reproductive and non-reproductive problems in domestic animals. In addition, emerging data indicates that ZEA may cause mRNA expression changes in the GCs. In general, E. asinus is more sensitive than swine to ZEA exposure. Finally, results of in vivo animal studies and in vitro tests are reported and discussed.

HERP depletion inhibits zearalenone-induced apoptosis through autophagy activation in mouse ovarian granulosa cells

HERP is an endoplasmic reticulum (ER) membrane protein and is strongly induced by stress conditions. A recent study has indicated that HERP cooperates in apoptosis during zearalenone (ZEA) treatment. However, regulatory mechanisms and the role of HERP in ZEA-induced apoptosis remain elusive in ovarian granulosa cells. In this study, MTT and flow cytometry assays demonstrated that ZEA gradually decreased cell viability and increased apoptosis in granulosa cells in a dose-dependent manner. Western blot analysis showed that ZEA significantly activated autophagy by upregulating LC3-II. Chloroquine (CQ) significantly increased LC3-II and induced granulosa cell apoptosis. Moreover, Western blot analysis showed that ZEA inhibited the mTOR and ERK1/2 signaling pathways. Furthermore, we found that ZEA activated ER stress by upregulating the ER stress-related proteins GRP78, HERP and CHOP. 4-PBA significantly decreased GRP78, HERP, CHOP and LC3-II. In addition, knockdown of HERP (shHERP) significantly protected ovarian granulosa cells from apoptosis induced by ZEA. We found that HERP depletion activated autophagy and ERK1/2 signaling pathways, while it inhibited the mTOR and caspase-dependent mitochondrial signaling pathways. In summary, autophagy and ER stress cooperated in apoptosis induced by ZEA; HERP depletion inhibits ZEA-induced apoptosis of ovarian granulosa cells through autophagy activation and apoptotic pathway inhibition.

Zearalenone Exposure Enhanced the Expression of Tumorigenesis Genes in Donkey Granulosa Cells via the PTEN/PI3K/AKT Signaling Pathway

Zearalenone (ZEA) is a natural contaminant existing in food and feed products that exhibits a negative effect on domestic animals’ reproduction. Donkeys possess high economic value in China and are at risk of exposure to ZEA. However, few information is available on ZEA-induced toxicity and no report on toxicity in donkeys can be found in scientific literature. We investigated the biological effects of ZEA exposure on donkey granulosa cells (dGCs) by using RNA-seq analysis. ZEA at 10 and 30 μM were administered to GCs within 72 h of in vitro culture. ZEA at 10 μM significantly altered the tumorigenesis associated genes in dGCs. Exposure to 10 and 30 μM ZEA treatment significantly reduced mRNA expression of PTEN, TGFβ, ATM, and CDK2 genes, particularly, the ZEA treatment significantly increased the expression of PI3K and AKT genes. Furthermore, immunofluorescence, RT-qPCR, and Western blot analysis verified the gene expression of ZEA-exposed GCs. Collectively, these results demonstrated the deleterious effect of ZEA exposure on the induction of ovarian cancer related genes via the PTEN/PI3K/AKT signaling pathway in dGCs in vitro.

Comparison of the toxic effects of different mycotoxins on porcine and mouse oocyte meiosis

Background

Aflatoxin B1 (AFB1), deoxynivalenol (DON), HT-2, ochratoxin A (OTA), zearalenone (ZEA) are the most common mycotoxins that are found in corn-based animal feed which have multiple toxic effects on animals and humans. Previous studies reported that these mycotoxins impaired mammalian oocyte quality. However, the effective concentrations of mycotoxins to animal oocytes were different.

Methods

In this study we aimed to compare the sensitivity of mouse and porcine oocytes to AFB1, DON, HT-2, OTA, and ZEA for mycotoxin research. We adopted the polar body extrusion rate of mouse and porcine oocyte as the standard for the effects of mycotoxins on oocyte maturation.

Results and Discussion

Our results showed that 10 μM AFB1 and 1 μM DON significantly affected porcine oocyte maturation compared with 50 μM AFB1 and 2 μM DON on mouse oocytes. However, 10 nM HT-2 significantly affected mouse oocyte maturation compared with 50 nM HT-2 on porcine oocytes. Moreover, 5 μM OTA and 10 μM ZEA significantly affected porcine oocyte maturation compared with 300 μM OTA and 50 μM ZEA on mouse oocytes. In summary, our results showed that porcine oocytes were more sensitive to AFB1, DON, OTA, and ZEA than mouse oocytes except HT-2 toxin.

Fusarium Molds and Mycotoxins: Potential Species-Specific Effects

This review summarizes the information on biochemical and biological activity of the main Fusarium mycotoxins, focusing on toxicological aspects in terms of species-specific effects. Both in vitro and in vivo studies have centered on the peculiarity of the responses to mycotoxins, demonstrating that toxicokinetics, bioavailability and the mechanisms of action of these substances vary depending on the species involved, but additional studies are needed to better understand the specific responses. The aim of this review is to summarize the toxicological responses of the main species affected by Fusarium mycotoxins.

Differentiation of sow and mouse ovarian granulosa cells exposed to zearalenone in vitro using RNA-seq gene expression

Zearalenone (ZEA), a natural contaminant found in feed, has been shown to have a negative impact on domestic animal reproduction, particularly in pigs. There are species-specific differences in the ZEA-induced toxicity pattern. Here, we investigated the different biological effects of ZEA exposure on porcine and mouse granulosa cells, using RNA-seq analysis. We treated murine and porcine granulosa cells with 10 μM and 30 μM ZEA during 72 h of culturing, in vitro. The results showed that 10 μM ZEA exposure significantly altered mitosis associated genes in porcine granulosa cells, while the same treatment significantly altered the steroidogenesis associated genes in mouse granulosa cells. Exposure to 30 μM ZEA resulted in significantly up-regulated expression of inflammatory related genes in porcine granulosa cells as well as the cancer related genes in mouse granulosa cells. Similarly, 30 μM ZEA exposure significantly decreased the expression of tumor suppressor factors in the mouse granulosa cells. Furthermore, immunofluorescence, RT-qPCR as well as western-blot analysis verified the different expression of related genes in ZEA exposed porcine and mouse granulosa cells. Collectively, these results illustrate the presence of species differences with regards to ZEA effects between porcine and mouse ovarian granulosa cells, in vitro.

Measurement of urinary concentrations of the mycotoxins zearalenone and sterigmatocystin as biomarkers of exposure in mares

Mycotoxins may affect animal health, including reproduction. Little is known about the clinical relevance of exposure of horses to contaminated feed. This study aimed at (i) monitoring the levels of the mycotoxins zearalenone (ZEN), with its metabolites α- and β-zearalenol (α- and β-ZOL), and sterigmatocystin (STC) in urine samples from thoroughbred mares in Japan and (ii) relating these findings to the potential effects on reproductive efficacy of breeding mares. Sixty-three urine samples of breeding mares from 59 breeding farms were used. Urine samples and reproductive records were collected from each mare when it was presented to the stallion station. Urinary concentrations of ZEN, α- and β-ZOL, and STC were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). ZEN, α- and β-ZOL were measurable in the urine of all examined mares, indicating the prevalence of ZEN in equine feeds. In seven of the 63 samples, STC was also detected at levels ranging from 1.3 to 18.0 pg/mg creatinine. No significant correlation between the concentrations of mycotoxins and pregnancy status was observed. In conclusion, measurement of mycotoxins in urine samples is a useful non-invasive method for monitoring the systemic exposure of mares to multiple mycotoxins.

Protective effect of Crocin against zearalenone-induced oxidative stress in liver and kidney of Balb/c mice

Zearalenone (ZEN) is a mycotoxin from Fusarium species commonly found in many food commodities and known to cause reproductive disorders. Several studies have shown that ZEN is hematotoxic and hepatotoxic and causes several alterations of immunological parameters. In the present study, we aimed to evaluate the protective effect of Crocin (CRO), a natural carotenoid, against ZEN-induced toxicity in both renal and hepatic tissues of Balb/c mice. We demonstrated that ZEN (40 mg/kg body weight (b.w.)) induced oxidative stress in both kidney and liver as monitored by measuring the malondialdehyde (MDA) level, the protein carbonyl generation, the catalase and superoxide dismutase activity, and the expression of the heat shock proteins (Hsp70). However, combined treatment of ZEN with different doses of CRO (50, 100, and 250 mg/kg b.w.) significantly reduced ZEN-induced alterations in all tested oxidative stress markers. It could be concluded that CRO was effective in the protection against ZEN-induced toxicity in the liver and kidney of Balb/c mice.

In vitro effects of deoxynivalenol and zearalenone major metabolites alone and combined, on cell proliferation, steroid production and gene expression in bovine small-follicle granulosa cells

The effects of deoxynivalenol (DON) and zearalenone (ZEA) on reproduction in ruminants are unclear. This study was performed to evaluate the impact of DON and ZEA hydroxylated metabolites, α-zearalenol (α-Zol) and β-zearalenone (β-Zol), on cell proliferation, steroidogenesis and gene expression using bovine granulosa cells (GC). Cell proliferation was negatively affected after exposure to β-Zol at 31 μM and after exposure to α-Zol (3.1 μM) alone and combined with DON (3.3 μM). DON and α-Zol decreased steroidogenesis, while β-Zol at high concentration had stimulatory effects. DON and β-Zol increased CYP19A1 mRNA abundance. CYP11A1 mRNA abundance was stimulated by DON, alone and combined with α-Zol and β-Zol, whereas was inhibited by β-Zol alone. Generally mycotoxins effects on cell proliferation, steroidogenesis and gene expression were influenced by the presence or absence of IGF1. In conclusion DON and ZEA metabolites may impair in vitro cell proliferation, steroid production and gene expression in cattle.

Individual and combined effects of deoxynivalenol and α-zearalenol on cell proliferation and steroidogenesis of granulosa cells in cattle

This study was conducted to evaluate the impact of deoxynivalenol (DON) and zearalenone (ZEA) metabolite, α-zearalenol (α-Zol), on cell proliferation and steroidogenesis of bovine large (LG) follicle granulosa cells (GC). LGGC were obtained from bovine ovarian follicles (8-22 mm) and were cultured for 2 days in medium containing 10% fetal bovine serum followed by 1 or 2 days in serum-free medium without (control) or with treatments. Three different experiments were performed using different dosages of DON and α-Zol and in different combinations and a fourth experiment evaluated estradiol effects on granulosa cell proliferation. DON inhibited progesterone (P4) and estradiol (E2) production at high dose. α-Zol alone and in combination with DON increased cell growth. Estradiol inhibited cell growth indicating α-Zol is not acting as an estrogen agonist. This study demonstrates that α-Zol and DON can impact in vitro GC function, however further studies will be required to better understand the mechanism of action and reproductive effects of Fusarium mycotoxins.

Altered oxidative stress, apoptosis/autophagy, and epigenetic modifications in Zearalenone-treated porcine oocytes

ZEN affected porcine oocyte maturation and early embryonic development. Oxidative stress, autophagy and apoptosis occurred. Aberrant epigenetic modifications were also observed.

Biochemical changes and oxidative stress induced by zearalenone in the liver of pregnant rats

The aim of the present research was to examine the toxic influence of different doses of zearalenone (ZEN) on the liver, especially oxidative stress induced by ZEN on the liver. A total of 48 pregnant Sprague-Dawley rats were randomly assigned into 4 treatments groups with 12 animals in each. The rats were fed with a normal diet treated with 0 mg/kg (control), 50 mg/kg (treatment 1), 100 mg/kg (treatment 2), or 150 mg/kg (treatment 3) ZEN in feed on gestation days (GDs) 0–7 and then all the rats were fed with a normal diet on GDs 8–20. The experimental period lasted 21 days. The results showed that exposure to ZEN induced increase in aspartate amino transferase, alanine aminotransferase, and alkaline phosphatase activities and decrease in total protein and albumin content in a dose-dependent manner and also induce decrease in superoxide dismutase and glutathione peroxidase activities and increase in malondialdehyde content in a dose-dependent manner in the serum and the liver. The increased transcription of cytochrome P450 2E1 (CYP2E1) was detected in the liver after exposure to ZEN. These results suggested that ZEN not only caused damage in the liver of pregnant rats in a dose-dependent manner but also induced the messenger RNA expression of CYP2E1 in the liver.

Analysis of individual and combined effects of ochratoxin A and zearalenone on HepG2 and KK-1 cells with mathematical models

Ochratoxin A (OTA) and Zearalenone (ZEA) are widespread mycotoxins that contaminate foodstuffs simultaneously, but sufficient data regarding their mixed toxicities are lacking. This study aims to analyze the style of combined effects of OTA and ZEA on cells of their target organs. For this purpose, cytotoxicity was determined in HepG2 and KK-1 cells treated with single and combined forms of OTA and ZEA. Furthermore, we have analyzed the data using two mathematical models based on the concepts of concentration addition (CA) and independent addition (IA). By analyzing data with nonlinear regression, toxins applied singly showed classic sigmoid dose-response curves in HepG2 cells whereas in KK-1 cells hormetic responses were observed. Exposure to equieffective mixtures of OTA and ZEA showed additive effects, irrespective of different nonlinear regression models used. Our results demonstrate that IA is an appropriate concept to account for mixture effects of OTA and ZEA. The results in ROS generation indicate a departure from additivity to antagonism or synergism at different concentrations, probably due to potential interaction during ROS production. This study shows that a risk assessment of mycotoxins should account for mixture effects, and prediction models are valuable tools for mixture assessment.

Application of mycotoxin adsorbent to cattle feed contaminated with zearalenone: urinary zearalenone excretion and association with anti-Müllerian hormone

This study investigated (1) protective effects of a commercially available mycotoxin adsorbent (MA) and (2) endocrine effects of in vivo exposure to zearalenone (ZEA) in cattle. The sample included a Japanese Black female cattle herd (MYT herd) that displayed persistently high urinary ZEA concentrations. A second herd (NM herd) was used as a control. Three groups from each herd were assessed: MX (n=6; MA mixed with concentrate), TD (n=6; MA applied as topdressing with the concentrate), and a positive control (n=6; no MA application). Urine and blood samples were collected at the start of MA supplementation (day 0), on the final day of supplementation (day 16), and on the final day of the sampling period (day 58 for MYT herd and day 50 for NM herd). Urinary ZEA concentrations (pg/mg of creatinine) were measured by ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Haematological and serum biochemical analyses were performed to monitor hepatic, renal, nutritional, and mineral intake statuses. Ovulation status was assessed by progesterone (P4) and antral follicle population by anti-Müllerian hormone (AMH) levels. The urinary concentrations of ZEA and its metabolites in the MX and TD groups were significantly lower (P<0.05) at day 16 compared with the control group, as measured by LC-MS/MS. The valid ratio of AMH-positive (≯0.08 ng/ml) cattle was significantly higher in the NM herd than in the MYT herd without affecting the P4-positive (≯3 ng/ml) ratio, suggesting different populations of antral follicles. Significant differences were also observed between the MX and the control in aspartate aminotransferase and γ-glutamyltransferase at day 58, suggesting preventive effects of MA supplementation. Our field trial indicated that MA supplementation of a ZEA-contaminated diet has beneficial effects in reducing ZEA absorption from the intestine of cattle, maintaining endocrine homeostasis and reversing hepatic effects.

Mycotoxins and female reproduction: in vitro approaches

Exposure to mycotoxins has been linked to adverse effects on female reproduction by interfering with the synthesis, metabolism or degradation of steroid hormones, interaction with steroid receptors or impairing oocyte maturation and competence. To assess such effects, many studies initially focussed on possible endocrine actions of mycotoxins using specific cell lines known to express key enzymes involved in the synthesis of steroid hormones. Using these models, zearalenone, deoxynivalenol, ochratoxin A, T-2 and HT-2 toxins, and aflatoxin B1 were claimed to be endocrine active substances. As yet, zearalenone is the only mycotoxin for which a direct interaction with oestrogen receptors could be demonstrated, classifying this mycotoxin as an endocrine disruptor. Mycotoxin exposure of complex cell systems like ovarian follicles at the earliest (primordial) to most advanced (pre-ovulatory) stages can serve not only as the first indication of the potential of a mycotoxin to affect female reproduction, but also provides insight in specific mechanisms involved in such an effect and identifies vulnerable phases in follicle development. Zearalenone is the most widely studied mycotoxin regarding female reproduction, but effects on oocyte maturation have also been demonstrated for deoxynivalenol. Exposure to zearalenone impairs the formation of primordial, while its metabolite ?-zearalenol is more harmful to fertilised oocytes than zearalenone itself. This short overview aims to provide an introduction into the different models, such as cell lines and oocytes, commonly used to assess the potential adverse effects of mycotoxins on female reproduction.

Effects of zearalenone on oxidative stress and inflammation in weanling piglets

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by the fungi of Fusarium genera. Piglets were fed for 18 days with a control or a ZEN (316 ppb) contaminated diet. At the end of the experiment tissue samples were taken for assessment of: lymphocyte proliferation, monocytes and granulocytes respiratory burst, inflammatory cytokine synthesis in blood and liver, expression of genes involved in oxidative stress or in inflammation, plasma biochemical parameters, total antioxidant status and nitric oxide synthesis. In blood, ZEN increases the respiratory burst of monocytes and the inflammatory cytokine (TNF alpha, IL-1 beta, IFN gamma) synthesis, while in liver, ZEN decreases the synthesis of all inflammatory cytokines investigated. In liver and spleen, different effect on the expression of genes involved in oxidative stress and inflammation was observed. While in liver, ZEN decrease the expression of cyclooxigenase gene, but increase the expression of glutathione peroxydase and catalase genes; in spleen, ZEN induces a decrease of the superoxide dismutase gene expression together with an increase of the cyclooxigenase. In conclusion, our results showed that liver, spleen and blood may also be target tissues in weanling piglets fed ZEN contaminated diet, with different effects on oxidative stress and inflammation.

Ca(2+)-dependent suicidal erythrocyte death following zearalenone exposure

Zearalenone, a cereal mycotoxin with mycoestrogen activity and effect on fertility, is known to trigger apoptosis of a variety of nucleated cell types including hematopoietic progenitor cells. In analogy to apoptosis of nucleated cells, eryptosis, the suicidal death of erythrocytes, leads to cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the erythrocyte surface. The most important stimulator of eryptosis is an increase in cytosolic Ca(2+) activity ([Ca(2+)]i). The present study explored whether zearalenone triggers eryptosis. Erythrocyte volume was estimated from forward scatter, phosphatidylserine exposure at the erythrocyte surface from annexin-V binding, hemolysis from hemoglobin release, and [Ca(2+)]i from Fluo3 fluorescence. A 48-h exposure to zearalenone (≥25 μM) was followed by a significant increase in [Ca(2+)]i and annexin-V binding, and a significant decrease in forward scatter. The effect on annexin-V binding was significantly blunted in the nominal absence of extracellular Ca(2+). Zearalenone stimulates the suicidal erythrocyte death, an effect at least partially due to stimulation of Ca(2+) entry.

Applications of flow cytometry to toxicological mycotoxin effects in cultured mammalian cells: a review

This review gives an overview of flow cytometry applications to toxicological studies of several physiological target sites of mycotoxins on different mammalian cell lines. Mycotoxins are secondary metabolites of fungi that may be present in food, feed, air and water. The increasing presence of mycotoxins in crops, their wide distribution in the food chain, and their potential for toxicity demonstrate the need for further knowledge. Flow cytometry has become a valuable tool in mycotoxin studies in recent years for the rapid analysis of single cells in a mixture. In toxicology, the power of these methods lies in the possibility of determining a wide range of cell parameters, providing valuable information to elucidate cell growth and viability, metabolic activity, mitochondrial membrane potential and membrane integrity mechanisms. There are studies using flow cytometry technique on Alternaria, Aspergillus, Fusarium and Penicillium mycotoxins including information about cell type, assay conditions and functional parameters. Most of the studies collected in the literature are on deoxynivalenol and zearalenone mycotoxins. Cell cycle analysis and apoptosis are the processes more widely investigated.

Occupational exposures to chemicals as a possible etiology in premature ovarian failure: a critical analysis of the literature

Premature ovarian failure (POF) is a cause of infertility that affects about 1% of women under 40, and is considered as idiopathic in 75% of cases. An occupational chemical origin has been identified at least once with 2-bromopropane, but human studies are rare and experimental data are sparse. This review aims to carry out a critical synthesis of knowledge of the chemical agents likely to affect follicular stock in humans and/or animals, by direct toxicity to follicles, or by increasing their recruitments. Of 140 chemical agents (or groups) studied, 20 have been identified as potentially damaging to the ovarian reserve. For the majority of toxic agents, only experimental data are currently available. At least four of these agents are likely to lead to POF in descendents (ethylene glycol methyl ether; 2,2-bis(bromomethyl)-1,3-propanediol; benzo[a]pyrene; dimethylbenzantracene). We propose a strategy aiming to encourage progress in identifying occupational factors responsible for POF.

Effects of zearalenone and its derivatives on porcine immune response

Zearalenone (ZEN), a mycotoxin produced by several Fusarium spp., is most commonly found as a contaminant in stored grain and has chronic estrogenic effects on mammals. In this in vitro study, we compared the effects of zearalenone (ZEN) and some of its derivatives: α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), and zearalanone (ZAN) on several peripheral blood mononuclear cell (PBMC) parameters: cytotoxicity, proliferation, as well as antibody and cytokine synthesis. The amounts of toxins necessary to inhibit viability, in a dehydrogenase enzyme activity assay (MTT test), by 50% were: 22.7 μM for ZEN, 29.1 μM for α-ZOL, 17.3 μM for β-ZOL and 26.3 μM for ZAN. The administration of 10 μM toxin induced a decrease in the ConA stimulated proliferation of PBMC by 19.6% for ZAN, 45.4% for ZEN, 43.6% for α-ZOL and 85.2% for β-ZOL, when compared to the control stimulated cells. Also, ZEN and its metabolites at concentrations higher than 5 μM induced a significant decrease of the IgG, IgA or IgM levels. Concentrations of 5 and 10 μM of ZEN and ZAN significantly decreased the TNF-α synthesis in the supernatant of the stimulated cells; 10 μM of ZAN also decreased IL-8 synthesis. In conclusion, our results show that ZEN and ZEN derivatives altered several parameters of the humoral and cellular immune response. Therefore, our results are clinically relevant as ZEN and its metabolites are frequent contaminants of animal feed and we have shown that intoxicated animals are incapable of inducing an adequate immune response.

Zearalenone and reproductive function in farm animals

Farm animals are exposed to zearalenone through the feed because of the widespread occurrence of this mycotoxin in cereals and clinical reproductive disorders due to mycotoxin effects are often reported in farm animal species. This review describes the metabolism, the mechanistic aspects, the clinical reproductive symptoms and the in vitro effects on functional parameters of oocytes and sperm cells induced by zearalenone and its derivatives in farm animals. The studies on in vitro effects allow to understand the action mechanisms of mycotoxins and, sometime, to explain the in vivo symptoms. The impairment of semen quality and female reproductive function induced by zearalenone could be a factor responsible for the reproductive failure in farm animals.

Cytotoxicity effects induced by Zearalenone metabolites, alpha Zearalenol and beta Zearalenol, on cultured Vero cells

Zearalenone (Zen) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium. It has been implicated in several mycotoxicosis in farm animals and in humans. The major metabolites of this mycotoxin in various species are alpha and beta Zearalenol. In vivo, Zen is mainly reduced to these alcoholic metabolites which cause reproductive tract disorders and impaired fertility due to their estrogenic activities. In this study, we examined the cytotoxicity of alpha and beta Zearalenol in cultured cells. For this purpose, the MTT assay was carried out and the influence of alpha and beta Zearalenol on protein and DNA syntheses was assessed. To evaluate the cell stress caused by these two metabolites, oxidative stress measured by MDA induction and stress protein induction (Hsp 70, Hsp 27) were tested. Results showed that alpha and beta Zearalenol were metabolites that caused cytotoxicity by inhibiting cell viability, protein and DNA syntheses and inducing oxidative damage and over-expression of stress proteins. However, the Zen metabolites exhibited lower toxicity than Zen, with beta zearalenol being the more active of the two metabolites.