Toxicological effects of regulated mycotoxins and persistent organochloride pesticides: In vitro cytotoxic assessment of single and defined mixtures on MA-10 murine Leydig cell line

Persistent organic pollutants dysregulate energy homeostasis in human ovaries in vitro

Exposure to persistent organic pollutants (POPs), such as dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs), has historically been linked to population collapses in wildlife. Despite international regulations, these legacy chemicals are still currently detected in women of reproductive age, and their levels correlate with reduced ovarian reserve, longer time-to-pregnancy, and higher risk of infertility. However, the specific modes of action underlying these associations remain unclear. Here, we examined the effects of five commonly occurring POPs - hexachlorobenzene (HCB), p,p'-dichlorodiphenyldichloroethylene (DDE), 2,3,3',4,4',5-hexachlorobiphenyl (PCB156), 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB180), perfluorooctane sulfonate (PFOS) - and their mixture on human ovaries in vitro. We exposed human ovarian cancer cell lines COV434, KGN, and PA1 as well as primary ovarian cells for 24 h, and ovarian tissue containing unilaminar follicles for 6 days. RNA-sequencing of samples exposed to concentrations covering epidemiologically relevant levels revealed significant gene expression changes related to central energy metabolism in the exposed cells, indicating glycolysis, oxidative phosphorylation, fatty acid metabolism, and reactive oxygen species as potential shared targets of POP exposures in ovarian cells. Alpha-enolase (ENO1), lactate dehydrogenase A (LDHA), cytochrome C oxidase subunit 4I1 (COX4I1), ATP synthase F1 subunit alpha (ATP5A), and glutathione peroxidase 4 (GPX4) were validated as targets through qPCR in additional cell culture experiments in KGN. In ovarian tissue cultures, we observed significant effects of exposure on follicle growth and atresia as well as protein expression. All POP exposures, except PCB180, decreased unilaminar follicle proportion and increased follicle atresia. Immunostaining confirmed altered expression of LDHA, ATP5A, and GPX4 in the exposed tissues. Moreover, POP exposures modified ATP production in KGN and tissue culture. In conclusion, our results demonstrate the disruption of cellular energy metabolism as a novel mode of action underlying POP-mediated interference of follicle growth in human ovaries.

Perfluorooctanoic acid inhibits androgen biosynthesis in rat immature Leydig cells

Perfluorooctanoic acid (PFOA) is a commonly used short-chain synthetic perfluoroalkyl agent. Immature Leydig cells (ILCs) are localized in the testis and responsible for androgen biosynthesis and metabolism. Although PFOA shows toxicity in the reproductive system, it is not clear if it disrupts the function of ILCs. In the present study, primary ILCs were isolated from 35-day-old rats and exposed to a range of PFOA concentrations (0, 0.01, 0.1, or 1 μM). It was determined that 0.1 or 1 μM PFOA reduced total androgen biosynthesis in ILCs. Specifically, 22R-hydroxycholesterol (22R), and pregnenolone (P5) mediated androgen biosynthesis were reduced by 0.1 μM PFOA. PFOA also selectively downregulated mRNA and protein expressions of steroidogenic enzymes including LHCGR, CYP11A1, 3β-HSD1, and NR5A1 at 0.01, 0.1, or 1 μM. Further analysis revealed that 0.1 μM PFOA inhibited CYP11A1 and 3β-HSD1 enzyme activities. However, PFOA did not significantly affect androgen metabolism and turnover under any of the conditions tested. And PFOA gavaging to 35-day-old rats at 5 or 10 mg/kg for 7 or 14 days also reduced serum androgen levels secreted by ILCs. Moreover, PFOA gavaging also downregulated the mRNA and protein expression levels of LHCGR, CYP11A1, 3β-HSD1, and NR5A1 in vivo. Taken together, these findings suggest that PFOA inhibits androgen biosynthesis in ILCs by selectively targeting key enzymes in the synthesis pathway.

Co-exposure ochratoxin A and triadimefon influenced the hepatic glucolipid metabolism and intestinal micro-environment in mice

Ochratoxin A (OTA) is a mycotoxin, and triadimefon (TDF) is a triazole fungicide. These compounds are prevalent in the environment, and their residues have been detected in crops. However, the precise health risks associated with mycotoxins and fungicides are not fully elucidated. In this work, five-week-old mice were gavage with OTA (0.3 and 1.5 mg/kg/day), TDF (10 and 50 mg/kg/day), and OTA + TDF (0.3 + 10 and 1.5 + 50 mg/kg/day) for 28 days. Exposure to OTA, TDF, and OTA + TDF led to significant alterations in liver total cholesterol (TC), triglyceride (TG), and glucose (GLU) levels, as well as in genes associated with glycolipid metabolism in mice. Reduced acylcarnitine levels in serum indicated that OTA, TDF, and co-exposure inhibited fatty acid (FA) β-oxidation. Furthermore, OTA and TDF disrupted the integrality of the gut barrier function and altered the structure of the intestinal microbiota. These findings suggested that OTA, TDF, and their co-exposure might disrupt the intestinal barrier, alter the structure of the microbiota, and subsequently inhibit FA β-oxidation, indicating the interference of OTA and TDF with glycolipid-related intestinal barrier dysfunction. Moreover, our data revealed a toxic additive effect between OTA and TDF, providing a foundation for assessing the combined toxicity risk of mycotoxins and fungicides.

The Effect of Mycotoxins and Their Mixtures on Bovine Spermatozoa Characteristics

There is growing concern about the effects of mycotoxins on mammalian reproduction. Although the effects of single mycotoxins have been well documented, the impact of their mixtures on spermatozoon quality is less known. Here, frozen-thawed semen (n = 6 bulls) was in-vitro-cultured (2 h) without (control) or with (i) a single mycotoxin [zearalenone (ZEN), ochratoxin A (OTA), toxin 2 (T2), and diacetoxyscirpenol (DAS)] in a dose-response manner; (ii) binary mixtures (OTA + T2, OTA + ZEN, OTA + DAS, ZEN + T2, DAS + T2 and ZEN + DAS); or (iii) ternary mixtures (OTA + DAS + T2, OTA + ZEN + T2, and ZEN + DAS + T2). Then, the spermatozoa quality was characterized according to its plasma- and acrosome-membrane integrity, mitochondrial membrane potential, and oxidation status by a flow cytometer. Exposure to single mycotoxins or binary mixtures did not affect the spermatozoa characteristics. However, exposure to the ternary mixtures, OTA + DAS + T2 and OTA + ZEN + T2, reduced (p < 0.05) the mitochondrial membrane potential relative to the control. In addition, OTA + ZEN + T2 increased (p < 0.05) the proportion of spermatozoa with reactive oxygen species relative to the control. The most suggested interaction effect between the mycotoxins was found to be an additive one. A synergistic interaction, mainly regarding the oxidation status of the spermatozoa, was also found between the mycotoxins. The current study sheds light on the potential risk of exposing spermatozoa to a mycotoxin mixture.

Screening of the phytochemical constituents of Teucrium polium extract and evaluation of their prophylactic role against the oxidative damage and cytotoxicity of Aflatoxin B1 in rats

Aflatoxin B1 (AFB1) is common carcinogen causing acute and chronic hepatocyte injuries. This study aimed to determine the bioactive components of Teucrium polium methanolic extract (TPE) and to evaluate their protective role against AFB1-induced oxidative damage, cytotoxicity, and genotoxicity in rats. Six groups of male albino rats were treated orally for 4 weeks including the control group, the ِAFB1-treated group (80 μg/kg b.w.), the groups treated with low (LD) or high (HD) dose TPE (50 or 100 mg/kg b.w.), and the groups treated with AFB1 plus TEP (LD) or TPE (HD). Blood and serum samples were collected for different assays. The GC-MS identified 34 compounds, the major compounds were pinene, germacrene D, α-cadinol, α-thujene, epi-bicyclosesquiphellandrene, and limonene. Animals that received AFB1 showed significant changes in all indicators of oxidative stress, biochemistry, cytokines, MNPCEs, comet tail formation in bone marrow, mRNA expression of inflammatory-related genes, Nrf2, and iNOS beside histological changes in the liver. TPE at the two doses tested showed insignificant changes in all tested parameters. The extract could normalize most of these parameters and the hepatic structure in AFB1-treated animals in a dose-dependent fashion. therefore, we concluded that TPE supplementation is effective for protection against AFB1 in endemic areas.

Deoxynivalenol: Emerging Toxic Mechanisms and Control Strategies, Current and Future Perspectives

Deoxynivalenol (DON) is the most frequently present mycotoxin contaminant in food and feed, causing a variety of toxic effects in humans and animals. Currently, a series of mechanisms involved in DON toxicity have been identified. In addition to the activation of oxidative stress and the MAPK signaling pathway, DON can activate hypoxia-inducible factor-1α, which further regulates reactive oxygen species production and cancer cell apoptosis. Noncoding RNA and signaling pathways including Wnt/β-catenin, FOXO, and TLR4/NF-κB also participate in DON toxicity. The intestinal microbiota and the brain-gut axis play a crucial role in DON-induced growth inhibition. In view of the synergistic toxic effect of DON and other mycotoxins, strategies to detect DON and control it biologically and the development of enzymes for the biodegradation of various mycotoxins and their introduction in the market are the current and future research hotspots.

Combined toxicity of food-borne mycotoxins and heavy metals or pesticides

Food can be contaminated by multiple classes of toxic substances, mainly including mycotoxins, heavy metals and pesticides, which leads to a possibility of simultaneous exposure to two or more food contaminants for humans. Thus, it is necessary to examine whether the combined exposure could result in enhanced toxicity. Initially, the studies on the combined toxicity of food contaminants mainly focus on the mixtures of same classes of food contaminants due to their co-occurrence feature in foodstuffs, such as mixtures of mycotoxins or mixtures of heavy metals. Given the possibility that consumers are likely exposed to mixtures of different classes of food contaminants, recently, studies on the combined toxicity of different classes of food contaminants have been receiving increasing attentions. In this review article, we summarize the findings of combined toxicity studies related to co-exposure to food-borne mycotoxins and other classes of food contaminants mainly heavy metals or pesticides, and propose issues that need to be addressed in future studies for more accurately performing risk assessment of co-exposure to mycotoxins and other classes of food contaminants.

Distribution, toxicity, interactive effects, and detection of ochratoxin and deoxynivalenol in food: A review

Mycotoxins are secondary metabolites of fungi that cause severe damage to agricultural products and food in the food supply chain. These detrimental pollutants have been directly linked with poor socioeconomic patterns and human health issues. Among the natural micropollutants, ochratoxin A (OTA) and deoxynivalenol (DON) are widely distributed in food materials. The primary occurrence of these mycotoxins is reported in almost all cereal grains and fresh agro-products. Both mycotoxins have shown harmful effects, such as nephrotoxic, hepatotoxic, and genotoxic effects, in humans due to their complex structural formation during the degradation/acetylation reaction. In addition, improper preharvest, harvest, and postharvest handling tend to lead to the formation of OTA and DON in various food commodities, which allows different harmful fungicides in practice. Therefore, this review provides more insight into the distribution and toxicity of OTA/DON in the food matrix and human health. Furthermore, the interactive effects of OTA/DON with co-contaminated organic and inorganic compounds are discussed. Finally, international regulation and mitigation strategies for detoxication are critically evaluated to meet food safety and good agriculture practices.

Downregulation of microRNA-96-5p protects TM3 cells against zearalenone toxicity via targeting ATG9A

Male infertility factor accounts for ~50% of all infertility cases, and traditional treatments for male infertility are limited. The association between the dysfunction of Leydig cells and hypospermatogenesis is essential for developing novel treatment methods for male infertility. It was previously stated that elevated expression of microRNA (miR)-96-5p was associated with the toxicological response of Leydig cells to treatment with zearalenone (ZEN). However, the exact role of miR-96-5p in Leydig cells remains to be illustrated. The mouse Leydig cell line TM3 was used in the present study to investigate the role of miR-96-5p. ZEN was used to induce cell injury in TM3 cells. Cell Counting Kit-8 assay and the Ki67 staining method were used to evaluate cell viability. Reverse transcription-quantitative PCR was used to determine the expression levels of miR-96-5p. In addition, a dual luciferase assay was used to investigate the target of miR-96-5p. Annexin V/propidium iodide staining was performed to detect cell apoptosis. Western blot analysis was used to detect the expression levels of certain proteins. Finally, monodansylcadaverine (MDC) and LC3 staining were applied for monitoring the level of autophagy. ZEN inhibited the proliferation of TM3 cells in a dose-dependent manner. In addition, the level of miR-96-5p were significantly increased in ZEN-treated TM3 cells. Meanwhile, inhibition of miR-96-5p could reverse ZEN-induced decrease in viability in TM3 cells. Moreover, ZEN notably inhibited autophagy in TM3 cells and this phenomenon was reversed by the application of the miR-96-5p inhibitor. Autophagy related 9A (ATG9A) was identified as the biological target of miR-96-5p. The results derived from MDC and LC3 staining demonstrated that downregulation of miR-96-5p expression levels protected TM3 cells against ZEN toxicity by regulating autophagy. Inhibition of miR-96-5p expression protected TM3 cells against ZEN via targeting ATG9A. Therefore, miR-96-5p may serve as a potential biomarker for male infertility.

Effects of deoxynivalenol exposure at peripuberty over testicles of rats: structural and functional alterations

Deoxynivalenol (DON) is related to reduced reproductive performance in males and females in several species. Children and adolescents showed a high risk of exposure to DON, however, no study has evaluated reproductive effects of DON at puberty. The present study aimed to evaluate the effects of DON at peripuberty on the testicles of pubertal rats. To achieve this, 10 Wistar rats (28 days old) were fed for 28 days with a DON-contaminated diet (9.4 mg/kg) or a control diet. After the experimental period, rats (56 days old) were euthanised and the following evaluations were performed in the testicles: dynamics of spermatogenesis, tubular morphometry, number of Sertoli cells and Leydig cells, analysis of caspase-3 expression, and the index of cell proliferation using the nucleolus organising regions (NOR) method. Ingestion of DON-contaminated diet induced a significant reduction in the number of Sertoli and Leydig cells and the number of seminiferous tubules in stage XIV. A significant increase in the number of NORs in seminiferous tubules in stage I-VI was observed in animals receiving the DON diet. No significant difference was noted in tubular morphometry or caspase-3 expression. Taken together, our results unravelled that the peripubertal exposure to DON compromised the testicular structure of pubertal rats, changing the dynamics of spermatogenesis.

Aflatoxins: History, Significant Milestones, Recent Data on Their Toxicity and Ways to Mitigation

In the early 1960s the discovery of aflatoxins began when a total of 100,000 turkey poults died by hitherto unknown turkey "X" disease in England. The disease was associated with Brazilian groundnut meal affected by Aspergillus flavus. The toxin was named Aspergillus flavus toxin-aflatoxin. From the point of view of agriculture, aflatoxins show the utmost importance. Until now, a total of 20 aflatoxins have been described, with B1, B2, G1, and G2 aflatoxins being the most significant. Contamination by aflatoxins is a global health problem. Aflatoxins pose acutely toxic, teratogenic, immunosuppressive, carcinogenic, and teratogenic effects. Besides food insecurity and human health, aflatoxins affect humanity at different levels, such as social, economical, and political. Great emphasis is placed on aflatoxin mitigation using biocontrol methods. Thus, this review is focused on aflatoxins in terms of historical development, the principal milestones of aflatoxin research, and recent data on their toxicity and different ways of mitigation.

Effect of environmental contamination on female and male gametes - A lesson from bovines

Endocrine-disrupting compounds (EDCs) and foodborne contaminants are environmental pollutants that are considered reproductive toxicants due to their deleterious effects on female and male gametes. Among the EDCs, the phthalate plasticizers are of growing concern. In-vivo and in-vitro models indicate that the oocyte is highly sensitive to phthalates. This review summarizes the effects of di(2-ethylhexyl) phthalate and its major metabolite mono(2-ethyhexyl) phthalate (MEHP) on the oocyte. MEHP reduces the proportion of oocytes that fertilize, cleave and develop to the blastocyst stage. This is associated with negative effects on meiotic progression, and disruption of cortical granules, endoplasmic reticulum and mitochondrial reorganization. MEHP alters mitochondrial membrane polarity, increases reactive oxygen species levels and induces alterations in genes associated with oxidative phosphorylation. A carryover effect from the oocyte to the blastocyst is manifested by alterations in the transcriptomic profile of blastocysts developed from MEHP-treated oocytes. Among foodborne contaminants, the pesticide atrazine (ATZ) and the mycotoxin aflatoxin B1 (AFB1) are of high concern. The potential hazards associated with exposure of spermatozoa to these contaminants and their carryover effect to the blastocyst are described. AFB1 and ATZ reduce spermatozoa's viability, as reflected by a high proportion of cells with damaged plasma membrane; induce acrosome reaction, expressed as damage to the acrosomal membrane; and interfere with mitochondrial function, characterized by hyperpolarization of the membrane. ATZ and AFB1-treated spermatozoa show a high proportion of cells with fragmented DNA. Exposure of spermatozoa to AFB1 and ATZ reduces fertilization and cleavage rates, but not that of blastocyst formation. However, fertilization with AFB1- or ATZ-treated spermatozoa impairs transcript expression in the formed blastocysts, implying a carryover effect. Taken together, the review indicates the risk of exposing farm animals to environmental contaminants, and their deleterious effects on female and male gametes and the developing embryo.

Does low concentration mycotoxin exposure induce toxicity in HepG2 cells through oxidative stress?

The purpose of this study was to determine whether exposure to low concentrations of deoxynivalenol (DON), T-2 toxin (T-2) and patulin (PAT) in a human hepatocellular carcinoma cell line (HepG2) exerts toxic effects through mechanisms related to oxidative stress, and how cells deal with such exposure. Cell viability was determined by the MTT and protein content (PC) assays over 24, 48 and 72 h. The IC₅₀ values detected ranged from >10 to 2.53 ± 0.21 μM (DON), 0.050 ± 0.025 to 0.034 ± 0.007 μM (T-2) and 2.66 ± 0.66 to 1.17 ± 0.21 µM (PAT). The key players in oxidative stress are the generation of reactive oxygen species (ROS), lipid peroxidation (LPO) and mitochondrial membrane potential (MMP) dysfunction. The results obtained showed that PAT, DON and T-2 did not significantly increase LPO or ROS production with respect to the controls. Moreover, PAT and DON did not alter MMP, though T-2 increased MMP at the higher concentrations tested (17 and 34 nM). In conclusion, the exposure of HepG2 cells to nontoxic concentrations of T-2 condition them against subsequent cellular oxidative conditions induced by even higher concentrations of mycotoxin.

Bioactive compounds from Aspergillus niger extract enhance the antioxidant activity and prevent the genotoxicity in aflatoxin B1-treated rats

This study aimed to identify the bioactive compounds of the ethyl acetate extract of Aspergillus niger SH2-EGY using GC-MS and to evaluate their protective role against aflatoxin B₁ (AFB₁)-induced oxidative stress, genotoxicity and cytotoxicity in rats. Six groups of male Sprague-Dawley rats were treated orally for 4 weeks included the control group, AFB₁-treated group (80 μg/kg b.w); fungal extract (FE)-treated groups at low (140) or high dose (280) mg/kg b.w and the groups treated with AFB₁ plus FE at the two tested doses. The GC-MS analysis identified 26 compounds. The major compounds found were 1,2,3,4,6-Penta-trimethylsilyl Glucopyranose, Fmoc-L-3-(2-Naphthyl)-alanine, D-(-)-Fructopyranose, pentakis (trimethylsilyl) ether, bis (2-ethylhexyl) phthalate, trimethylsilyl ether-glucitol, and octadecanamide, N-(2- methylpropyl)-N-nitroso. The in vivo results showed that AFB₁ significantly increased serum ALT, AST, creatinine, uric acid, urea, cholesterol, triglycerides, LDL, carcinoembryonic antigen, alpha-fetoprotein, interleukin-6, Malondialdehyde, nitric oxide, Bax, caspase-3 and P53 mRNA expression, chromosomal aberrations and DNA fragmentation. It decreased serum TP, albumin, HDL, Bcl-2 mRNA expression, hepatic and renal TAC, SOD and GPx content and induced histological changes in the liver and kidney. FE prevented these disturbances in a dosage-dependent manner. It could be concluded that A. niger SH2-EGY extract is safe a promising agent for pharmaceutical and food industries.

Mitochondrial damage are involved in Aflatoxin B1-induced testicular damage and spermatogenesis disorder in mice

Aflatoxin B₁ (AFB₁) is an unavoidable environmental pollutants, which seriously endangers human and animal health. AFB₁ has male reproductive toxicity, yet the underlying mechanisms remain inconclusive. Mitochondra are a kind of crucial organelle for maintaining spermatogenesis in testis. Thus, we hypothesized that AFB₁ can impair mitochondria to aggravate testicular damage and spermatogenesis disorder. To verify this hypothesis, 48 male mice were intragastrically administered with 0, 0.375, 0.75 or 1.5 mg/kg body weight AFB₁ for 30 days, respectively. In this study, we found AFB₁ caused testicular histopathological lesions and spermatogenesis abnormalities, with the elevation of oxidative stress (increased H₂O₂, whereas decreased SOD and GSH). Significant mitochondria structure damage of germ cells and Leydig cells, MMP loss, ATP contents reduction, and inhibited activities of mitochondrial complexes I-IV in mice testis were found in AFB₁ treatment groups. Besides, AFB₁ inhibited mitochondrial biogenesis and mitochondrial dynamics, presenting as the decreased mRNA and protein expressions of PGC-1α, Nrf1, Tfam, Drp1, Fis1, Mfn1 and Opa1. The results revealed that the mitochondrial damage were involved in AFB₁-induced testicular damage and spermatogenesis disorder, providing a considerable direction to clarify potential mechanisms of AFB₁ reproductive toxicity.

Melatonin ameliorates ochratoxin A-induced oxidative stress and apoptosis in porcine oocytes

Melatonin is a hormone which is generated from pineal gland, and it is responsible for the regulation of wake-sleep cycle. Melatonin is a well-known antioxidant and free radical scavenger to protect against multiple type of tissue damage. While ochratoxin A (OTA) is a mycotoxin found widely in contaminated food and foodstuffs, which causes nephrotoxicity, hepatotoxicity, immunotoxicity, and reproductive damage in humans and animals. In present study we report the toxicity of OTA on porcine oocyte quality and the protective effects of melatonin on OTA-exposed oocytes. Using transcriptome analysis our results show that OTA exposure alters the expression of multiple genes in oocytes, indicating its effect on oocyte maturation. The cellular changes following OTA treatment are examined, and the results show that OTA adversely affects oocyte polar body extrusion, which is confirmed by the delay of Cdc2-mediated cell cycle progression. OTA exposure also disrupts meiotic spindle formation, which is confirmed by altered phosphorylated MAPK expression. RNA-seq screening and further fluorescence staining results show that OTA induces aberrant mitochondria distribution and oxidative phosphorylation defects, which then causes oxidative stress, followed by early apoptosis and autophagy. Treatment with melatonin significantly ameliorates oxidative stress and apoptosis, which further protects cell cycle and spindle formation in OTA-exposed oocytes. Collectively, these results show the protective effects of melatonin against defects induced by OTA during porcine meiotic oocyte maturation.

Maternal Exposure to T-2 Toxin Induces Changes in Antioxidant System and Testosterone Synthesis in the Testes of Mice Offspring

Simple Summary

This study investigated the effects of maternal T-2 toxin exposure on the development of testis in the mice offspring. The detrimental effects were assessed by testicular weight, antioxidant capacity, and testosterone synthesis and secretion. Studies have shown that the toxin carried by the mother has bad effects on the testicular development of offspring at puberty, affecting the antioxidant system and testosterone synthesis in the testis, but the maternal exposure of T-2 toxin had no significant impact on the testes of offspring after sexual maturity, suggesting the recovery of reproductive function.

Abstract

T-2 toxin, the most toxic member of trichothecene mycotoxin, is widely distributed in cereals, and has been extensively studied, but few studies focus on the toxicity of maternal exposure to offspring. This study focused on the effects of maternal exposure to T-2 toxin (during gestation and lactation) on the testicular development of mice offspring. Dams were orally administered with T-2 toxin at 0, 0.005, or 0.05 mg/kg body weight from the late stage of gestation to the end of lactation. Testicular samples of the mice offspring were collected on the postnatal day 21, 28, and 56. The results showed significant decreases in body weight and testicular weight on the postnatal day 28. Moreover, significant inhibition of antioxidant system and testosterone synthesis was detected on the postnatal day 28. Furthermore, there were significant decreases in the gene expression levels of StAR and 3β-HSD, which are involved in testosterone synthesis. In general, present results demonstrated that maternal exposure to T-2 toxin during gestation and lactation led to bad effects on the capacity of antioxidant system and inhibited testosterone synthesis in testes during pre-puberty with no significant effects on post-puberty.

T-2 toxin impairs male fertility by disrupting hypothalamic-pituitary-testis axis and declining testicular function in mice

T-2 toxin could impair male reproductive function. But, the toxicity mechanism is still unclear. In this study, male Kunming mice were orally administrated with T-2 toxin at the doses of 0, 0.5, 1 or 2 mg/kg body weight for 28 days. The fertility, body weight, reproductive organs volume, daily sperm production (DSP), and sperm malformation rate were detected. The expressions of testosterone (T) biosynthetic enzymes, luteinizing hormone (LH)-receptor, follicle stimulating hormone (FSH)-receptor and androgen binding protein (ABP) in testis were detected. The serum hormone level of gonadotropin-releasing hormone (GnRH), FSH, LH, T and progesterone (P), and the mRNA expression of GnRH, GnRH-receptor, LH and FSH were measured. These results demonstrated that T-2 toxin decreased body weight, reproductive organs volume and DSP, increased sperm malformation rate. T-2 toxin impaired fertility by decreasing the mating index, fertility index, numbers of implantation sites and viable fetuses, and increasing the number of animal with resorptions. Meantime, T-2 suppressed testicular function by inhibiting T biosynthesis and decreasing FSHR, LHR and ABP expression. Furthermore, the serum reproductive hormone contents and key factors expression of hypothalamic-pituitary-testis (HPT) axis were decreased by T-2 toxin. In summary, T-2 toxin impaired the male fertility by disrupting HPT axis and impairing testicular function.

Spermatogenesis disorder caused by T-2 toxin is associated with germ cell apoptosis mediated by oxidative stress

T-2 toxin is an unavoidable contaminant in human food, animal feeds, and agricultural products. T-2 toxin has been found to impair male reproductive function. But, few data is available that reveals the reproductive toxicity mechanism. In the study, male Kunming mice were orally administrated with T-2 toxin at the doses of 0, 0.5, 1 or 2 mg/kg body weight for 28 days. The body and reproductive organs weight, the concentration, malformation rate and ultrastructure of sperm in cauda epididymis were detected. Oxidative stress biomarkers and apoptosis were also measured in testes. Histological change of testes was performed by H&E and TUNEL staining. T-2 toxin down-regulated body and reproductive organs (testis, epididymis and seminal vesicle) weight, sperm concentration, increased sperm malformation rate and damaged the ultrastructure of sperm and structure of testes. T-2 toxin treatment increased the reactive oxygen species (ROS) and malondialdehyde content, while, decreased the total anti-oxidation capacity (T-AOC) and the superoxide dismutase activity in testes. T-2 toxin exposure increased the TUNEL-positive germ cells, the activities and mRNA expressions of caspase-3, caspase-8 and caspase-9, the mRNA expression of Bax, and inhibited the Bcl-2 mRNA expression. Furthermore, the expressions of caspase-3, caspase-8 caspase-9 and Bax were positively correlated with ROS level, but negatively correlated with T-AOC in testis. In summary, T-2 toxin caused spermatogenesis disorder associated with the germ cell apoptosis medicated by oxidative stress, impairing the male reproductive function.

Deoxynivalenol Modulates the Viability, ROS Production and Apoptosis in Prostate Cancer Cells

Deoxynivalenol (DON), known as vomitoxin, a type B trichothecene, is produced by Fusarium. DON frequently contaminates cereal grains such as wheat, maize, oats, barley, rye, and rice. At the molecular level, it induces ribosomal stress, inflammation and apoptosis in eukaryotic cells. Our findings indicate that DON modulates the viability of prostate cancer (PCa) cells and that the response to a single high dose of DON is dependent on the androgen-sensitivity of cells. DON appears to increase reactive oxygen species (ROS) production in cells, induces DNA damage, and triggers apoptosis. The effects of DON application in PCa cells are influenced by the mitogen-activated protein kinase (MAPK) and NFΚB- HIF-1α signaling pathways. Our results indicate that p53 is a crucial factor in DON-associated apoptosis in PCa cells. Taken together, our findings show that a single exposure to high concentrations of DON (2-5 µM) modulates the progression of PCa.

Ochratoxin A suppresses proliferation of Sertoli and Leydig cells in mice

Ochratoxin A (OTA) is a mycotoxin originating from Penicillium and Aspergillus. In addition to toxic effects in various tissues and cells, including neurons, immune cells, hepatocytes, and nephrons, it also causes carcinogenesis and teratogenesis. Although the negative effects of OTA with respect to the pathogenesis of diseases and the malfunction of various organs have been studied widely, the biological signaling mechanisms in testicular cells are less well known. Therefore, we determined the hazardous effect of OTA in two types of testicular cells: TM3 (mouse Leydig cells) and TM4 (mouse Sertoli cells). Treatment with OTA led to a significant decrease in the proliferation of both cell lines, as revealed by an increased proportion of cells in the sub-G1 phase. In addition, the phosphorylation of signaling molecules belonging to the PI3K (Akt, P70S6K, and S6) and MAPK (ERK1/2 and JNK) pathways was regulated by OTA in a dose-dependent manner in TM3 and TM4 cells. Furthermore, the combination treatment of OTA and signaling inhibitors (LY294002, U0126, or SP600125) exerted synergistic antiproliferative effects in TM3 and TM4 cells. OTA also reduced the concentration of calcium ions in the cytosol and mitochondria, which disrupted the calcium homeostasis necessary for maintaining the normal physiological functions of testicular cells. In conclusion, the results of the present study demonstrate the mechanism underlying the antiproliferative effects of OTA in mouse testicular cells. Exposure to OTA may result in abnormal sperm maturation and the failure of spermatogenesis, which leads to male infertility.

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 exposure and adverse reproductive health outcomes in Africa: a review

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