Vitamin E Mitigates Apoptosis in Ovarian Granulosa Cells by Inhibiting Zearalenone-Induced Activation of the PERK/eIF-2α/ATF4/Chop Signaling Pathway

A study aimed to investigate the signaling pathway of zearalenone (ZEA) leading to the apoptosis of ovarian granulosa cells (GCs) and explore the potential of vitamin E (VE) in alleviating ZEA-induced apoptosis of GCs. We constructed an apoptosis model for GCs based on exposure to the environmental toxin ZEA. Transcriptome analysis revealed that ZEA induced endoplasmic reticulum stress by activating the ATF4-Chop pathway. The addition of inhibitors targeting the estrogen receptor (ER) demonstrated that ZEA activates the ATF4-Chop pathway through ER-beta. As a strong antioxidant, VE is thought to mitigate ZEA-induced toxicity. Interestingly, molecular docking analysis at the PERK active site of the endoplasmic reticulum stress revealed a high binding capacity of VE. VE supplementation reduced apoptosis in GCs and decreased the expression of p-eIF-2α, ATF4, and Chop. Mouse tests also demonstrated that VE supplementation effectively mitigated ovarian dysfunction induced by ZEA, as evidenced by increased body weight gain, reduced oxidative stress, and decreased cell death. In summary, the present study demonstrates that ZEA activates the PERK-eIF-2α-ATF4-Chop pathway through ERβ, leading to endoplasmic reticulum stress and apoptosis of GCs. Conversely, VE inhibits the PERK/eIF-2α/ATF4/Chop signaling pathways, mitigating endoplasmic reticulum stress and improving ZEA-induced reproductive toxicity.

Whole-transcriptome analysis reveals the effect of retinoic acid on small intestinal mucosal injury in cage-stressed young laying ducks

Retinoic acid (RA) is an active derivative of vitamin A and is involved in a variety of physiological processes, including cell growth, antioxidant, and inflammation. However, the role of RA in intestinal oxidative stress injury in caged-stressed laying ducks is unknown. In this study, we analyzed the effect and underlying mechanism of RA supplementation on intestinal damage in cage-stressed young laying ducks. One hundred and sixty laying ducks were divided into 5 treatment groups, including a control group (CR) and 4 treatment groups exposed to different RA concentrations (2,500, 5,000, 7,500 and 10,000 IU/kg, TG1 to TG4). The experimental period comprised a 7-d prefeeding period and a 10-d experimental feeding period, for a total of 17 d. Phenotypic analysis revealed that compared with the control group, RA addition increased the intestinal villus height and the villus-to-crypt ratio; decreased the crypt depth (P < 0.01); decreased the serum diamine oxidase and D-lactate concentrations (P < 0.05); increased the serum antioxidant capacity and intestinal antioxidant gene expression levels (P < 0.05); and increased the expression levels of tight junction-related genes, with the greatest effect observed in TG2 group. Our further whole-transcriptome analysis of duodenum tissues from CR and TG2 ducks revealed 706 differentially expressed mRNAs (DEmRNAs), 357 differentially expressed lncRNAs (DElncRNAs), 14 differentially expressed circRNAs (DEcircRNAs), and 4 differentially expressed miRNAs (DEmiRNAs). These DEGs are involved in calcium signaling, NOD-like receptor signaling, pyruvate metabolism, Jak-STAT signaling, Wnt signaling, riboflavin metabolism, and the adherens junction and tight junction pathways. The results of omics and marker gene expression analysis suggested that RA treatment may play a role in endoplasmic reticulum stress (ERS) and apoptosis. In conclusion, the addition of RA to the diet improved intestinal injury by improving the redox homeostasis of intestinal cells associated with ERS, enhancing the intestinal tight junction structure and alleviating the apoptosis of intestinal epithelial cells; moreover, 5,000 IU/kg RA was determined to be the most appropriate concentration for supplementation.

Selenium-Chitosan Protects Porcine Endometrial Epithelial Cells from Zearalenone-induced Apoptosis via the JNK/SAPK Signaling Pathway

This study was designed to assess whether selenium-chitosan (Se-CTS) can protect porcine endometrial epithelial cells (PEECs) against damage and apoptosis induced by zearalenone (ZEA) via modulating the JNK/SAPK signaling pathway. The cell cycle, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and apoptosis rates of porcine endometrial epithelial cells were determined, as well as the expression levels of genes related to the SAPK/JNK signaling pathway. The results showed that 3.0 µmol/L Se-CTS decreased the percentage of ZEA-induced G1 phase in PEECs (P < 0.01), whereas 1.5 and 3.0 µmol/L Se-CTS increased the percentage of ZEA-induced percentage of G2 phase of PEECs (P < 0.01). Further, Se-CTS at 1.5 and 3.0 µmol/L improved the ZEA-induced decrease in MMP (P < 0.01), whereas Se-CTS at 0.5, 1.5, and 3.0 µmol/L reduced the increase in ROS levels and apoptosis rate induced by ZEA in PEECs (P < 0.01 or P < 0.05). Furthermore, 3.0 µmol/L Se-CTS ameliorated the increase in the expression of c-Jun N-terminal kinase (JNK), apoptosis signal-regulated kinase (ASK1), and c-Jun induced by ZEA (P < 0.01) and the reduction in mitogen-activated protein kinase kinase 4 (MKK4) and protein 53 (p53) expression (P < 0.01), while 1.5 µmol/L Se-CTS improved the expression of ASK1 and c-Jun induced by ZEA (P < 0.05). The results proved that Se-CTS alleviates ZEA-induced cell cycle stagnation, cell mitochondrial damage, and cell apoptosis via decreasing ZEA-produced ROS and modulating the JNK/SAPK signaling pathway.

Toxicity, biodegradation, and nutritional intervention mechanism of zearalenone

Zearalenone (ZEA), a global mycotoxin commonly found in a variety of grain products and animal feed, causes damage to the gastrointestinal tract, immune organs, liver and reproductive system. Many treatments, including physical, chemical and biological methods, have been reported for the degradation of ZEA. Each degradation method has different degradation efficacies and distinct mechanisms. In this article, the global pollution status, hazard and toxicity of ZEA are summarized. We also review the biological detoxification methods and nutritional regulation strategies for alleviating the toxicity of ZEA. Moreover, we discuss the molecular detoxification mechanism of ZEA to help explore more efficient detoxification methods to better reduce the global pollution and hazard of ZEA.

Zearalenone triggers programmed cell death and impairs milk fat synthesis via the AKT-mTOR-PPARγ-ACSL4 pathway in bovine mammary epithelial cells

Zearalenone (ZEN), a mycotoxin from Fusarium fungi, impairs fertility and milk production in female animals; however, the mechanisms remain poorly understood. Using the bovine mammary epithelial cells (MAC-T) as the model, this study investigated the impacts of ZEN on programmed cell death (PCD) and milk fat synthesis and explored the underlying mechanism. We found that 10 ng/mL prolactin (PRL) notably enhanced the differentiation of MAC-T cells, promoting the expression of genes related to the synthesis of milk fat, protein, and lactose. Next, the toxic effects of different doses of ZEN on the differentiated MAC-T with PRL treatment were determined. 10 and 20 μM ZEN significantly reduced cell viability, induced oxidative stress, and triggered PCD (e.g., apoptosis and necrosis). Notably, ZEN exposure downregulated the mRNA/protein levels of critical factors involved in milk fat synthesis by disrupting the AKT-mTOR-PPARγ-ACSL4 pathway. Interestingly, melatonin (MT), known for its antioxidant properties, protected against the above ZEN-induced effects by enhancing the binding of PPARγ to the promoter regions of ACSL4, which led to the upregulated expression of the ACSL4 gene. These results underscored the potential of MT to mitigate the adverse effects of ZEN on mammary cells, highlighting a way for potential therapeutic intervention.

Real-life exposure to Fusarium toxins deoxynivalenol and zearalenone triggers apoptosis and activates NLRP3 inflammasome in bovine primary theca cells

Cattle are deemed less susceptible to mycotoxins due to the limited internal exposure resulting from rumen microbiota activity. However, the significant amounts of Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) frequently detected in bovine follicular fluid samples suggest that they could affect ovarian function. Both mycotoxins trigger several patterns of cell death and activate the NLRP3 inflammasome in the intestine. In vitro studies have reported a number of adverse effects on bovine oocytes. However, the biological relevance of such findings with regard to realistic concentrations of DON and ZEN in bovine follicular fluid is still not clear. Hence, it is important to better characterize the effects of dietary exposure to DON and ZEN on the bovine ovary. Using bovine primary theca cells, this study investigated the effects of real-life patterns for bovine ovary exposure to DON and ZEN, but also DON metabolite DOM-1, on cell death and NLRP3 inflammasome activation. Exposure to DON starting from 0.1 μM significantly decreased theca cell viability. The kinetics of phosphatidylserine translocation and loss of membrane integrity showed that ZEN and DON, but not DOM-1, induce an apoptotic phenotype. qPCR analysis of the expression of NLRP3, PYCARD, IL-1β, IL-18, and GSDMD in primary theca cells at concentrations of mycotoxin previously reported in cow follicular fluid clearly indicated that DON and DOM-1 individually and in mixture, but not ZEN, activate NLRP3 inflammasome. Altogether, these results suggest that real-life dietary exposure of cattle to DON may induce inflammatory disorders in the ovary.

β-Sitosterol Suppresses Lipopolysaccharide-Induced Inflammation and Lipogenesis Disorder in Bovine Mammary Epithelial Cells

β-sitosterol, a natural plant steroid, has been shown to promote anti-inflammatory and antioxidant activities in the body. In this study, β-sitosterol was used to protect against lipopolysaccharide (LPS)-induced cell damage in bovine mammary epithelial cells, which are commonly studied as a cell model of mammary inflammatory response and lipogenesis. Results showed that treatment with a combination of LPS and β-sitosterol significantly reduced oxidative stress and inflammation, while increasing the expression of anti-apoptotic proteins and activating the hypoxia-inducible factor-1(HIF-1α)/mammalian target of rapamycin(mTOR) signaling pathway to inhibit apoptosis and improve lipid synthesis-related gene expression. Our finding suggests that β-sitosterol has the potential to alleviate inflammation in the mammary gland.

Tebuconazole Induces ER-Stress-Mediated Cell Death in Bovine Mammary Epithelial Cell Lines

Tebuconazole (TEB) is a triazole fungicide used to increase crop production by controlling fungi, insects, and weeds. Despite their extensive use, people are concerned about the health risks associated with pesticides and fungicides. Numerous studies have defined the cellular toxicity of triazole groups in pesticides, but the mechanisms of TEB toxicity in bovine mammary gland epithelial cells (MAC-T cells) have not yet been studied. Damage to the mammary glands of dairy cows directly affects milk production. This study investigated the toxicological effects of TEB on MAC-T cells. We found that TEB decreases both cell viability and proliferation and activates apoptotic cell death via the upregulation of pro-apoptotic proteins, such as cleaved caspases 3 and 8 and BAX. TEB also induced endoplasmic reticulum (ER) stress via the upregulation of Bip/GRP78; PDI; ATF4; CHOP; and ERO1-Lα. We found that TEB induced mitochondria-mediated apoptotic MAC-T cell death by activating ER stress. This cell damage eventually led to a dramatic reduction in the expression levels of the milk-protein-synthesis-related genes LGB; LALA; CSN1S1; CSN1S2; and CSNK in MAC-T cells. Our data suggest that the exposure of dairy cows to TEB may negatively affect milk production by damaging the mammary glands.

Estrogenic and Non-Estrogenic Disruptor Effect of Zearalenone on Male Reproduction: A Review

According to some estimates, at least 70% of feedstuffs and finished feeds are contaminated with one or more mycotoxins and, due to its significant prevalence, both animals and humans are highly likely to be exposed to these toxins. In addition to health risks, they also cause economic issues. From a healthcare point of view, zearalenone (ZEA) and its derivatives have been shown to exert many negative effects. Specifically, ZEA has hepatotoxicity, immunotoxicity, genotoxicity, carcinogenicity, intestinal toxicity, reproductive toxicity and endocrine disruption effects. Of these effects, male reproductive deterioration and processes that lead to this have been reviewed in this study. Papers are reviewed that demonstrate estrogenic effects of ZEA due to its analogy to estradiol and how these effects may influence male reproductive cells such as spermatozoa, Sertoli cells and Leydig cells. Data that employ epigenetic effects of ZEA are also discussed. We discuss literature data demonstrating that reactive oxygen species formation in ZEA-exposed cells plays a crucial role in diminished spermatogenesis; reduced sperm motility, viability and mitochondrial membrane potential; altered intracellular antioxidant enzyme activities; and increased rates of apoptosis and DNA fragmentation; thereby resulting in reduced pregnancy.

Zearalenone Promotes LPS-Induced Oxidative Stress, Endoplasmic Reticulum Stress, and Accelerates Bovine Mammary Epithelial Cell Apoptosis

Both zearalenone (ZEA) and lipopolysaccharide (LPS) can induce oxidative stress, and even apoptosis in bovine mammary epithelial cells (MAC-T), but not much attention has been given to the synergistic effect of ZEA and LPS. In this study, we treated MAC-T cells with different concentrations of LPS (1, 10, 50, and 100 μg/mL) and ZEA (5, 15, and 30 μM) to induce cell damage. Previous results show that MAC-T cell viability decreases with increasing LPS concentration. Meanwhile, 1 µg/mL LPS and ZEA were selected for combined treatment in subsequent studies. It was found that co-treatment with ZEA and LPS increases the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), decreases mitochondrial membrane potential (MMP), and superoxide dismutase (SOD), and reduces glutathione (GSH). ZEA and LPS are found to activate endoplasmic reticulum (ER) stress by increasing the expression of glucose-regulated protein 78 kDa (GRP78), activating transcription factor 6 (ATF6) and C/EBP homologous protein (CHOP). It increases cell apoptosis by suppressing the expression of the anti-apoptotic protein B-cell lymphoma-2 (Bcl-2), indicated by up-regulation of Bcl2-associated X protein (Bax) and Cysteinyl aspartate-specific proteinases 3 (caspase-3) expression. The above results suggest that the synergistic effect of ZEA and LPS aggravate cytotoxicity.

Zearalenone Induces MLKL-Dependent Necroptosis in Goat Endometrial Stromal Cells via the Calcium Overload/ROS Pathway

Zearalenone (ZEA) is a fungal mycotoxin known to exert strong reproductive toxicity in animals. As a newly identified type of programmed cell death, necroptosis is regulated by receptor-interacting protein kinase 1 (RIPK1), receptor-interacting protein kinase 3 (RIPK3), and mixed-lineage kinase domain-like pseudokinase (MLKL). However, the role and mechanism of necroptosis in ZEA toxicity remain unclear. In this study, we confirmed the involvement of necroptosis in ZEA-induced cell death in goat endometrial stromal cells (gESCs). The release of lactate dehydrogenase (LDH) and the production of PI-positive cells markedly increased. At the same time, the expression of RIPK1 and RIPK3 mRNAs and P-RIPK3 and P-MLKL proteins were significantly upregulated in ZEA-treated gESCs. Importantly, the MLKL inhibitor necrosulfonamide (NSA) dramatically attenuated gESCs necroptosis and powerfully blocked ZEA-induced reactive oxygen species (ROS) generation and mitochondrial dysfunction. The reactive oxygen species (ROS) scavengers and N-acetylcysteine (NAC) inhibited ZEA-induced cell death. In addition, the inhibition of MLKL alleviated the intracellular Ca²⁺ overload caused by ZEA. The calcium chelator BAPTA-AM markedly suppressed ROS production and mitochondrial damage, thus inhibiting ZEA-induced necroptosis. Therefore, our results revealed the mechanism by which ZEA triggers gESCs necroptosis, which may provide a new therapeutic strategy for ZEA poisoning.

Adverse Effects of Fusarium Toxins in Ruminants: A Review of In Vivo and In Vitro Studies

With an increased knowledge of the mechanism of action of Fusarium mycotoxins, the concept that these substances are deleterious only for monogastric species is obsolete. Indeed, most mycotoxins can be converted into less toxic compounds by the rumen microflora from healthy animals. However, mycotoxin absorption and its conversion to more toxic metabolites, as well as their impact on the immune response and subsequently animal welfare, reproductive function, and milk quality during chronic exposure should not be neglected. Among the Fusarium mycotoxins, the most studied are deoxynivalenol (DON), zearalenone (ZEN), and fumonisins from the B class (FBs). It is remarkable that there is a paucity of in vivo research, with a low number of studies on nutrient digestibility and rumen function. Most of the in vitro studies are related to the reproductive function or are restricted to rumen incubation. When evaluating the production performance, milk yield is used as an evaluated parameter, but its quality for cheese production is often overlooked. In the present review, we summarize the most recent findings regarding the adverse effects of these mycotoxins with special attention to dairy cattle.

Protective Effects of Taraxasterol against Deoxynivalenol-Induced Damage to Bovine Mammary Epithelial Cells

Deoxynivalenol (DON), a mycotoxin produced by Fusarium graminearum, is one of the most prevalent contaminants in livestock feed and causes very large losses to animal husbandry every year. Taraxasterol, isolated from Taraxacum officinale, has anti-inflammatory, antioxidative stress, and antitumor effects. In the present study, bovine mammary epithelial cells (MAC-T) were used as a model, and different concentrations of taraxasterol (0, 1, 5, 10, and 20 μg/mL) were used to protect against DON-induced cell damage. The results showed that taraxasterol at a concentration of 10 μg/mL significantly increased cell viability. Analysis of lactate dehydrogenase (LDH) levels indicated that taraxasterol substantially decreased LDH release caused by DON. Taraxasterol effectively alleviated the depletion of glutathione (GSH), the increase in the lipid peroxidation of malondialdehyde (MDA), the reduction in total superoxide dismutase (T-SOD) activity, and the decrease in total antioxidant capacity (T-AOC) induced by DON. The results further showed that taraxasterol reduced the accumulation of reactive oxygen species (ROS). Taraxasterol was found to relieve endoplasmic reticulum (ER) stress by suppressing the expression of glucose-regulated protein 78 kDa (GRP78), activating transcription factor 6 (ATF6), activating transcription factor 4 (ATF4) and the transcription factor C/EBP homologous protein (CHOP), and reducing cell apoptosis by suppressing the expression of caspase-3 and Bcl2-associated X (BAX) and upregulating the expression of the antiapoptotic protein B-cell lymphoma-2 (Bcl-2). Our research results indicate that taraxasterol could alleviate DON-induced damage to MAC-T 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.

The Role of Tea Tree Oil in Alleviating Palmitic Acid-Induced Lipid Accumulation in Bovine Hepatocytes

Tea tree oil (TTO) plays an important role in lipid metabolism, alleviating the inflammatory responses. Fatty liver is associated with lipid accumulation in hepatocytes, leading to inflammation. However, there is very limited information on the effects of TTO on lipid accumulation, and inflammation in bovine hepatocytes. This study aimed to evaluate whether TTO alleviates palmitic acid (PA)-induced lipid accumulation in bovine hepatocytes. Hepatocytes isolated from mid-lactating Holstein cows were pretreated with 100 μM PA for 72 h. Cells were either pretreated with PA alone (PA group) or with PA followed by 0.00625% TTO treatment for 12 h (PT group). Expression of fatty acid oxidant genes increased (P < 0.05) while fatty acid synthesis genes decreased (P < 0.05) in the PT group compared with the PA group. PA treatment resulted in increased (P < 0.05) expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), but these increases were less in the PT group (P < 0.05). Compared to the PA group, expression of phosphorylated (p)-p65 and p-inhibitor κBα (p-IκBα) was suppressed (P < 0.05) by TTO treatment. TTO treatment limited (P < 0.05) the increase in intracellular reactive oxygen species (ROS) and prevented (P < 0.05) a reduction in mitochondrial membrane potential observed in response to PA treatment. Expression of endoplasmic reticulum (ER) stress genes was reduced (P < 0.05) in the PT group compared with the PA group. Our results suggest that TTO treatment attenuates the effects of PA in hepatocytes, leading to fatty acid oxidation, decreased fatty acid synthesis, suppressed inflammatory response, and reduced ER stress. Taken together, the results of this study suggest that TTO treatment may be a promising therapeutic approach to imbalanced lipid homeostasis, inflammation and ER stress in dairy cows shortly before and after calving.

Fluroxypyr-1-methylheptyl ester causes apoptosis of bovine mammary gland epithelial cells by regulating PI3K and MAPK signaling pathways and endoplasmic reticulum stress

Fluroxypyr-1-methylheptyl ester (FPMH) is an auxin herbicide that is widely applied to crops and pastures to block growth of post-emergence weeds. Several studies have reported the toxicity of FPMH in aquatic vertebrates. However, the adverse impacts of FPMH on mammals, including domestic animals, have not been reported. The purpose of our current study is to assess the impact of FPMH on the bovine mammary system and milk production. To evaluate the toxicity of FPMH on the mammary glands of lactating cows, the bovine mammary gland epithelial cell line, MAC-T, was exposed to various concentrations (0, 5, 7.5, 10, 15, and 20 μM) of FPMH for 24 h, and then various assessments were performed. The results showed that FPMH dose-dependently reduced MAC-T cell viability following exposure to FPMH and induced mitochondrial depolarization and apoptosis. FPMH also modulated signaling through the PI3K and MAPK pathways. In addition, the expression levels of proteins related to endoplasmic reticulum (ER) stress were upregulated, indicating induction of ER stress, and calcium homeostasis was disrupted following FPMH treatment. In conclusion, our investigation suggests that FPMH may be toxic to the bovine mammary system and may decrease dairy production.

Zearalenone exposure impairs organelle function during porcine oocyte meiotic maturation

Zearalenone (ZEN) is one of the secondary metabolites of Fusarium and is regarded as a common contaminant of foodstuffs especially corn products. ZEN is considered to be cytotoxic, tissue toxic, genotoxic and reproductive toxic, which acts as a serious threat for humans and animals. In this study, we investigated the effects of ZEN on organelle function during porcine oocyte meiotic maturation. Our results showed that the expansion of cumulus granulosa cells and the extrusion of oocyte polar body were disturbed after ZEN exposure. Besides the aberrant mitochondrial distribution and impaired mitochondrial membrane potential after ZEN treatment during porcine oocyte maturation. We also found the fluorescence intensity of ER was decreased, and ZEN exposure altered ER stress level, showing with the reduced expression of GRP78. We also found that the spindle cortex distribution of Golgi apparatus was disrupted in ZEN-exposed oocytes, which was confirmed by the decreased level of GM130, moreover, our data also showed that Rab11-based vesical transport was disturbed, indicating the Golgi apparatus function was disrupted. Besides, the fluorescence intensity of lysosome was significantly increased, indicating the protein degradation and the potential autophagy occurrence after ZEN treatment. Thus, our results demonstrated that exposure to ZEN affected porcine oocyte meiotic maturation through its wide effects on organelle function for protein synthesis, transport and degradation.

Tannic acid repair of zearalenone-induced damage by regulating the death receptor and mitochondrial apoptosis signaling pathway in mice

Zearalenone (ZEA) is an estrogenic toxin produced by Fusarium strains, that is widely present in crops, and endangers the reproductive system of animals. Tannic acid (TA) is a natural polyphenolic substance that is widespread in the roots, stems, and leaves of plants, and has special pharmacological activity. This study was designed to investigate the therapeutic effect of TA on ZEA-induced ovarian damage in mice and to explore the molecular mechanism involved. Ninety healthy Kunming female mice were divided into six equal groups. All the groups but the control group were administered daily with ZEA [10 mg/kg body weight (bw)] orally, for 7 days, to induce damage to the reproductive system. Some groups were also administered with TA (50, 100, and 200 mg/bw) for 7 days. Mice were euthanized 24 h later to allow for collection of serum and ovaries. TA can effectively alleviate the appearance of congestion and redness of the ovary, caused by ZEA, and increase the number of healthy growing follicles. Moreover, the estrogen content and the levels of MDA and ROS in the ovaries can be effectively reduced by TA. It can also reduce the apoptosis of ovarian cells, decreases the protein expression of the estrogen receptor, Fas, Fasl, caspase-3, caspase-8, caspase-9, and Bax, and increases the protein expression of Bcl-2. Our study indicates that TA reduces the strong estrogen and oxidative damage induced by ZEA, and these therapeutic effects may be partially mediated by the death receptor and mitochondrial apoptosis signaling pathway.

In vitro exposure of sheep ovarian tissue to the xenoestrogens zearalenone and enterolactone: Effects on preantral follicles

The aim of this study was to evaluate the effect of 1 μmol/L zearalenone (ZEN) and 1 μmol/L enterolactone (ENL), alone or in combination, on the survival and morphology of in vitro cultured ovarian preantral follicles. Ovaries from 10 sheep were collected at a local abattoir and fragmented, and the ovarian pieces were submitted to in vitro culture for 3 days in the presence or absence of the test compounds. The morphology of primordial and primary follicles was impaired by ZEN, whereas that of cultured secondary follicles was improved by ENL. However, the combination of ENL with ZEN impaired the quality of primary and secondary follicles. Both ZEN and ENL induced apoptosis, but only ZEN was responsible for oocyte autophagy. None of these xenoestrogens affected endoplasmic reticulum stress as observed by the unaltered expression of ERP29. Differently from ZEN, ENL increased the expression of the efflux transporter ABCG2. In conclusion, although ENL can counteract the negative effects of ZEN on primordial and primary follicles, this positive effect is not similar to that observed in ovarian tissue cultures in the presence of ENL alone.

Deoxynivalenol and Zearalenone-Synergistic or Antagonistic Agri-Food Chain Co-Contaminants?

Deoxynivalenol (DON) and Zearalenone (ZEN) are two commonly co-occurring mycotoxins produced by members of the genus Fusarium. As important food chain contaminants, these can adversely affect both human and animal health. Critically, as they are formed prior to harvesting, their occurrence cannot be eliminated during food production, leading to ongoing contamination challenges. DON is one of the most commonly occurring mycotoxins and is found as a contaminant of cereal grains that are consumed by humans and animals. Consumption of DON-contaminated feed can result in vomiting, diarrhoea, refusal of feed, and reduced weight gain in animals. ZEN is an oestrogenic mycotoxin that has been shown to have a negative effect on the reproductive function of animals. Individually, their mode of action and impacts have been well-studied; however, their co-occurrence is less well understood. This common co-occurrence of DON and ZEN makes it a critical issue for the Agri-Food industry, with a fundamental understanding required to develop mitigation strategies. To address this issue, in this targeted review, we appraise what is known of the mechanisms of action of DON and ZEN with particular attention to studies that have assessed their toxic effects when present together. We demonstrate that parameters that impact toxicity include species and cell type, relative concentration, exposure time and administration methods, and we highlight additional research required to further elucidate mechanisms of action and mitigation strategies.

Vitamin E and selenium supplementation synergistically alleviate the injury induced by hydrogen peroxide in bovine granulosa cells

Dairy cows are susceptible to reproductive disorders, which are thought to be associated with oxidative stress. In the study, we investigated the effects of vitamin E (VE) and selenium (Se) on the proliferation, apoptosis, and steroidogenesis in bovine ovarian granulosa cells under hydrogen peroxide (H₂O₂) - induced oxidative stress and elaborated the underlying mechanisms. Our results showed that VE or Se could stimulate the granulosa cell proliferation, possibly due to up-regulating the expression of CCND1 and decreasing the P21 levels under oxidative stress. VE or Se treatment also increased the secretion of estradiol (E2) and progesterone (P4), which could be owing to improving the expression of genes associated with steroidogenesis (StAR, HSD3β1, and CYP19A1) expression. VE or Se treatment down-regulated the apoptosis-related genes (BAX, CASP3) expression and decreased cell apoptosis. Furthermore, VE or Se treatment inhibited reactive oxidative species (ROS) and malondialdehyde (MDA) generation, increased total antioxidant capacity (T-AOC), and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Additionally, VE or Se treatment also alleviated the endoplasmic reticulum stress, activated the nuclear factor erythroid 2-related factor 2 (NRF2), and up-regulated the expression of its downstream genes, including NQO1, HO-1, GCLM, GCLC. More importantly, compared with either VE or Se treatment alone, their combined treatment showed a better protective effect against oxidative damage. Overall, our results indicated that VE and Se synergistically stimulated the granulosa cell proliferation and steroidogenesis, decreased cell apoptosis, mitigated the endoplasmic reticulum stress by activating the NRF2 signal pathway.

Microcystin-LR induces ovarian injury and apoptosis in mice via activating apoptosis signal-regulating kinase 1-mediated P38/JNK pathway

As an emerging pollutant in the aquatic environment, microcystin-LR (MC-LR) can enter the body through multiple pathways, and then induce apoptosis and gonadal damage, affecting reproductive function. Previous studies focused on male reproductive toxicity induced by MC-LR neglecting its effects on females. The apoptotic signal-regulated kinase 1 (ASK1) is an upstream protein of P38/JNK pathway, closely associated with apoptosis and organ damage. However, the role of ASK1 in MC-LR-induced reproductive toxicity is unclear. Therefore, this study investigated the role of ASK1 in mouse ovarian injury and apoptosis induced by MC-LR. After MC-LR exposure, ASK1 expression in mouse ovarian granulosa cells was increased at the protein and mRNA levels, and decreased following pretreatment by antioxidant N-acetylcysteine, suggesting that MC-LR-induced oxidative stress has a regulatory role in ASK1 expression. Inhibition of ASK1 expression with siASK1 and NQDI-1 could effectively alleviate MC-LR-induced mitochondrial membrane potential damage and apoptosis in ovarian granulosa cells, as well as pathological damage, apoptosis and the decreased gonadal index in ovaries of C57BL/6 mice. Moreover, the P38/JNK pathway and downstream apoptosis-related proteins (P-P38, P-JNK, P-P53, Fas) and genes (MKK4, MKK3, Ddit3, Mef2c) were activated in vivo and vitro, but their activation was restrained after ASK1 inhibition. Data presented herein suggest that the ASK1-mediated P38/JNK pathway is involved in ovarian injury and apoptosis induced by MC-LR in mice. It is confirmed that ASK1 has an important role in MC-LR-induced ovarian injury, which provides new insights for preventing MCs-induced reproductive toxicity in females.

Polydatin Protects Bovine Mammary Epithelial Cells Against Zearalenone-Induced Apoptosis By Inhibiting Oxidative Responses and Endoplasmic Reticulum Stress

Zearalenone (ZEA) is a mycotoxin of the Fusarium genus that can cause endoplasmic reticulum (ER) stress and Apoptosis in bovine mammary epithelial cells (MAC-T). Polydatin (PD), a glycoside purified from Polygonum cuspidatum, has antioxidant properties. This study aimed to explore whether PD can alleviate ZEA-induced damage on bovine mammary epithelial cells (MAC-T). We found that incasing the concentration of ZEA (0, 7.5, 15, 30, 60, 90, 120, and 240 μM) gradually decreased the cell viability. PD treatment alone at 5, 10, and 20 μM did not affect cell viability. Follow-up studies then applied 30 μM of ZEA and 5 μM of PD to treat cells; the results showed that the ZEA + PD treatment group effectively reduced cell oxidative damage compared with the ZEA treatment group. The qPCR analysis showed that ZEA treatment significantly up-regulated the expression of ER stress-related genes, relative to the control. However, adding PD significantly down-regulated the expression of ER stress-related genes. The cell apoptosis detection results showed that, compared with the ZEA treatment group, the ZEA + PD treatment group down-regulated the Bax gene and up-regulated the Bcl-2 gene expressions, which reduced the cell apoptosis rate and Caspase-3 activity. Taken together, these results indicate that PD reduces ZEA-induced apoptosis by inhibiting oxidative damage and ER stress.

G-Protein-Coupled Estrogen Receptor (GPER)-Specific Agonist G1 Induces ER Stress Leading to Cell Death in MCF-7 Cells

The G-protein-coupled estrogen receptor (GPER) mediates rapid non-genomic effects of estrogen. Although GPER is able to induce proliferation, it is down-regulated in breast, ovarian and colorectal cancer. During cancer progression, high expression levels of GPER are favorable for patients’ survival. The GPER-specific agonist G1 leads to an inhibition of cell proliferation and an elevated level of intracellular calcium (Ca²⁺). The purpose of this study is to elucidate the mechanism of G1-induced cell death by focusing on the connection between G1-induced Ca²⁺ depletion and endoplasmic reticulum (ER) stress in the estrogen receptor positive breast cancer cell line MCF-7. We found that G1-induced ER Ca²⁺ efflux led to the activation of the unfolded protein response (UPR), indicated by the phosphorylation of IRE1α and PERK and the cleavage of ATF6. The pro-survival UPR signaling was activated via up-regulation of the ER chaperon protein GRP78 and translational attenuation indicated by eIF2-α phosphorylation. However, the accompanying pro-death UPR signaling is profoundly activated and responsible for ER stress-induced cell death. Mechanistically, PERK-phosphorylation-induced JNK-phosphorylation and IRE1α-phosphorylation, which further triggered CAMKII-phosphorylation, are both implicated in G1-induced cell death. Our study indicates that loss of ER Ca²⁺ is responsible for G1-induced cell death via the pro-death UPR signaling.