Evaluation of fetal skeletal malformations in deoxynivalenol-treated mice using microarray analysis

Retinoic Acid-PPARα Mediates β-Carotene Resistance to Placental Dysfunction Induced by Deoxynivalenol

Deoxynivalenol (DON), one of the most polluted mycotoxins in the environment and food, has been proven to have strong embryonic and reproductive toxicities. However, the effects of DON on placental impairment and effective interventions are still unclear. This study investigated the effect of β-carotene on placental functional impairment and its underlying molecular mechanism under DON exposure. Adverse pregnancy outcomes were caused by intraperitoneal injection of DON from 13.5 to 15.5 days of gestation in mice, resulting in higher enrichment of DON in placenta than in other tissue samples. Interestingly, 0.1% β-carotene dietary supplementation could significantly alleviate DON-induced pregnancy outcomes. Additionally, in vivo and in vitro placental barrier models demonstrated the association of DON-induced placental function impairment with placental permeability barrier disruption, angiogenesis impairment, and oxidative stress induction. Moreover, β-carotene regulated DON-induced placental toxicity by activating the expressions of claudin 1, zonula occludens-1, and vascular endothelial growth factor-A through retinoic acid-peroxisome proliferator-activated receptor α signaling.

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.

Deoxynivalenol exposure during pregnancy has adverse effects on placental structure and immunity in mice model

Deoxynivalenol (DON), a highly prevalent food contaminant, is known to induce reproductive and immunotoxicity in humans upon exposure. The present study focused on the consequences of exposure to DON during pregnancy for placental barrier and immune function, as well as fetal survival. Female mice received diets contaminated with DON (6.25 and 12.5 mg/kg of diet), starting immediately after mating until the end of the experiment. On day 17 of pregnancy the animals were killed, and maternal and fetal samples were collected for further analysis. Feeding on DON-contaminated diets decreased fetal survival, and DON was detected at significant levels in the fetus. Placentae from DON-exposed mice revealed a reduction in expression of junctional proteins, ZO-1, E-cadherin and claudins, upregulation of AHR mRNA expressions, and increase in IFN-ꝩ, IL-6 and IL-4 production. In conclusion, results of this study demonstrate harmful effects of DON on the course of pregnancy and fetal survival, which might be due to immunological changes in maternal immune organs and placenta. Altogether, these data underline the importance of the quality of maternal diet during pregnancy as they clearly demonstrate the potential harmful effects of a commonly present food-contaminant.

Development of an Analytical Method for Quantitation of Deoxynivalenol by UPLC-MS-MS: A Preliminary Assessment of Gestational and Lactational Transfer in Rats

Deoxynivalenol (DON) is the most widely distributed trichothecene mycotoxin in grain-based foods and animal feed. Exposure to DON is widespread as it has been detected in food sources from around the world. The objective of this work was to develop a method to quantitate DON in biological matrices and apply it in a preliminary assessment of gestational and lactational transfer of DON following exposure of pregnant rats. The method used protein precipitation followed by ultra-performance liquid chromatography-tandem mass spectrometry. The method was evaluated in male Sprague Dawley rat plasma over the concentration range ∼2-1,000 ng/mL. The method was linear (r ≥ 0.99), accurate (mean relative error ≤ ±4.9%) and precise (relative standard deviation ≤ 5.5%). The mean absolute recovery was 85.9%. The limit of detection was 0.35 ng/mL. The method was also evaluated in gestational day (GD) 18 Hsd:Sprague Dawley®SD® dam plasma and fetal homogenate (mean % relative error ≤ ±16.9; % relative standard deviation ≤ 9.5). Concentrations of DON in dam plasma stored at -80°C for at least 29 days and in fetal homogenate for at least 43 days were within 97.9 to 120% of Day 0 concentrations, demonstrating that DON is stable in these matrices. The method was used to quantitate DON in rat maternal plasma, amniotic fluid, GD 18 fetuses and postnatal day (PND) 4 pups following exposure of dams to 0 (control) and 1 mg/kg DON beginning on GD 6 and continuing through gestation and lactation for a preliminary assessment of maternal transfer. In animals exposed to 1 mg/kg/day, similar concentration of DON was found in GD 18 dam plasma and fetuses, demonstrating significant gestational transfer. The concentration of DON in PND 4 dam plasma was similar to that in GD 18 dam plasma. However, DON was not detected in PND 4 pup plasma above the limit of detection of the assay, demonstrating absence of transfer of DON to pups via lactation.

Oral deoxynivalenol toxicity in Harlan Sprague Dawley (Hsd:Sprague Dawley® SD®) rat dams and their offspring

There is widespread human exposure to deoxynivalenol (DON), a fungal mycotoxin found globally in many grain-based foods and animal feed. Acute exposures to high levels of DON are associated with gastrointestinal effects and emesis in humans and some animals, but the effects of low-dose exposures throughout the lifetime, a more likely exposure scenario in humans, are understudied. Therefore, this study was designed to identify doses of DON that could be used to evaluate long-term toxicity following perinatal exposure. Time-mated Harlan Sprague Dawley (Hsd:Sprague Dawley® SD®) rats were administered 0, 0.03, 0.1, 0.3, 1, or 3 mg/kg/day of DON once daily via gavage starting on gestational day 6 through postnatal day (PND) 27. F1 animals were administered the same dose as their respective dams via gavage starting on PND 12 until PND 27. Animals were euthanized on PND 28. DON had no effect on maternal body weight or feed consumption at any dose. Findings were limited to the 3 mg/kg/day group: F0 females had smaller live litter sizes than controls and F1 pups had lower body weight (4-13%) compared to controls. By PND 28, F1 body weight, after adjustments for litter effects, was 10-13% lower than controls. Blood samples obtained on PND 28 showed no increases in frequencies of micronucleated immature erythrocytes in either F0 or F1 animals. In summary, doses of DON up to 3 mg/kg/day did not affect maternal survival or body weight. Doses of 3 mg/kg/day resulted in slight toxicity manifested as decreased body weight in the offspring. The no-observed effect level was 1 mg/kg/day.

Inhibiting the aberrant activation of Wnt/β-catenin signaling by selenium supplementation ameliorates deoxynivalenol-induced toxicity and catabolism in chondrocytes

Kashin-Beck disease (KBD) is an endemic degenerative osteoarticular disorder associated with physical disability and a heavy economic burden. Contamination by mycotoxin deoxynivalenol (DON) and selenium deficiency have been proposed to be key etiological factors for KBD, and can work together to aggravate the progression of KBD. Nevertheless, the mechanism of DON in KBD remains elusive. In the present study, exposure to DON dose-dependently suppressed cell viability and expression of pro-proliferation marker PCNA in human chondrocytes, whereas it enhanced lactate dehydrogenase release, cell apoptosis, and caspase-3/9 activity. In addition, DON incubation shifted metabolism homeostasis towards catabolism by suppressing the transcription of collagen II and aggrecan, and the production of sulphated glycosaminoglycans and TIMP-1, while increasing matrix metalloproteinase levels (MMP-1 and MMP-13). Mechanistically, DON exposure induced the activation of Wnt/β-catenin signaling. Intriguingly, blocking this pathway reversed the adverse effects of DON on cytotoxic damage and metabolism disruption to catabolism. Notably, supplementation with selenium reduced DON-induced activation of the Wnt/β-catenin pathway. Moreover, selenium addition abrogated cytotoxic injury and excessive pro-catabolic gene expression in chondrocytes upon DON conditions. These findings confirm that DON may facilitate the development of KBD by inducing cell injury, inhibiting matrix synthesis, and increasing cellular catabolism by activating the Wnt/β-catenin signaling, which were partially reversed by selenium supplementation. Thus, the current study may presents a new viewpoint for how selenium supplementation ameliorates the development of KBD by inhibiting DON-induced cytotoxic injury and metabolism imbalance in chondrocytes.

Fusarium Mycotoxins Disrupt the Barrier and Induce IL-6 Release in a Human Placental Epithelium Cell Line

Deoxynivalenol, T-2 toxin, and zearalenone, major Fusarium mycotoxins, contaminate human food on a global level. Exposure to these mycotoxins during pregnancy can lead to abnormalities in neonatal development. Therefore, the aim of this study was to investigate the effects of Fusarium mycotoxins on human placental epithelial cells. As an in vitro model of placental barrier, BeWo cells were exposed to different concentrations of deoxynivalenol, zearalenone or T-2 toxin. Cytotoxicity, effects on barrier integrity, paracellular permeability along with mRNA and protein expression and localization of junctional proteins after exposure were evaluated. Induction of proinflammatory responses was determined by measuring cytokine production. Increasing mycotoxin concentrations affect BeWo cell viability, and T-2 toxin was more toxic compared to other mycotoxins. Deoxynivalenol and T-2 toxin caused significant barrier disruption, altered protein and mRNA expression of junctional proteins, and induced irregular cellular distribution. Although the effects of zearalenone on barrier integrity were less prominent, all tested mycotoxins were able to induce inflammation as measured by IL-6 release. Overall, Fusarium mycotoxins disrupt the barrier of BeWo cells by altering the expression and structure of junctional proteins and trigger proinflammatory responses. These changes in placental barrier may disturb the maternal–fetal interaction and adversely affect fetal development.

DON-induced Changes in Bone Homeostasis in Mink Dams

Introduction

The aim of the study was to investigate the mechanical and geometric properties as well as bone tissue and mineral density of long bones in mink dams exposed to deoxynivalenol (DON) since one day after mating, throughout gestation (ca. 46 d) and lactation to pelt harvesting.

Material and Methods

Thirty clinically healthy multiparous minks (Neovison vison) of the standard dark brown type were used. After the mating, the minks were randomly assigned into two equal groups: non-treated control group and DON group fed wheat contaminated naturally with DON at a concentration of 1.1 mg·kg^-1 of feed.

Results

The final body weight and weight and length of the femur did not differ between the groups. However, DON contamination decreased mechanical endurance of the femur. Furthermore, DON reduced the mean relative wall thickness and vertical wall thickness of the femur, while vertical cortical index, midshaft volume, and cross-sectional moment of inertia increased. Finally, DON contamination did not alter bone tissue density, bone mineral density, or bone mineral content, but decreased the values of all investigated structural and material properties.

Conclusion

DON at applied concentration probably intensified the process of endosteal resorption, which was the main reason for bone wall thinning and the weakening of the whole bone.

Embryotoxicity Caused by DON-Induced Oxidative Stress Mediated by Nrf2/HO-1 Pathway

Deoxynivalenol (DON) belongs to the type B group of trichothecenes family, which is composed of sesquiterpenoid metabolites produced by Fusarium and other fungi in grain. DON may cause various toxicities, such as cytotoxicity, immunotoxicity, genotoxicity as well as teratogenicity and carcinogenicity. In the present study, we focus on a hypothesis that DON alters the expressions of Nrf2/HO-1 pathway by inducing embryotoxicity in C57BL/6 mouse (5.0, 2.5, 1.0, and 0 mg/kg/day) and BeWo cell lines (0 and 50 nM; 3 h, 12 h and 24 h). Our results indicate that DON treatment in mice during pregnancy leads to ROS accumulation in the placenta, which results in embryotoxicity. At the same time Nrf2/HO-1 pathway is up-regulated by ROS to protect placenta cells from oxidative damage. In DON-treated BeWo cells, the level of ROS has time-effect and dose-effect relationships with HO-1 expression. Moderate increase in HO-1 protects the cell from oxidative damage, while excessive increase in HO-1 aggravates the oxidative damage, which is called in some studies the "threshold effect". Therefore, oxidative stress may be the critical molecular mechanism for DON-induced embryotoxicity. Besides, Nrf2/HO-1 pathway accompanied by the "threshold effect" also plays an important role against DON-induced oxidative damage in this process.

Mechanism of deoxynivalenol effects on the reproductive system and fetus malformation: Current status and future challenges

Deoxynivalenol (DON) is a toxic fungal secondary metabolite produced by molds of the Fusarium genus, and it is known to cause a spectrum of diseases both in humans and animals, such as emesis, diarrhea, anorexia, immunotoxicity, hematological disorders, impairment of maternal reproduction, and fetal development. The recently revealed teratogenic potential of DON has received much attention. In various animal models, it has been shown that DON led to skeletal deformities of the fetus. However, the underlying mechanisms are not yet fully understood, and toxicological data are also scarce. Several animal research studies highlight the potential link between morphological abnormalities and changes of autophagy in the reproductive system. Because autophagy is involved in fetal development, maintenance of placental function, and bone remodeling, this mechanism has become a high priority for future research. The general aim of the present review is to deliver a comprehensive overview of the current state of knowledge of DON-induced reproductive toxicity in different animal models and to provide some prospective ideas for further research. The focus of the current review is to summarize toxic and negative effects of DON exposure on the reproductive system and the potential underlying molecular mechanisms in various animal models.

Integrated Transcriptional and Proteomic Analysis of Growth Hormone Suppression Mediated by Trichothecene T-2 Toxin in Rat GH3 Cells

Chronic exposure to trichothecenes is known to disturb insulin-like growth factor 1 and signaling of insulin and leptin hormones and causes considerable growth retardation in animals. However, limited information was available on mechanisms underlying trichothecene-induced growth retardation. In this study, we employed an integrated transcriptomics, proteomics, and RNA interference (RNAi) approach to study the molecular mechanisms underlying trichothecene cytotoxicity in rat pituitary adenoma GH3 cells. Our results showed that trichothecenes suppressed the synthesis of growth hormone 1 (Gh1) and inhibited the eukaryotic transcription and translation initiation by suppressing aminoacyl-tRNA synthetases transcription, inducing eukaryotic translation initiation factor 2-alpha kinase 2 (EIF2AK2) and reducing eukaryotic translation initiation factor 5 a. The sulfhydryl oxidases , protein disulfide isomerase,and heat shock protein 90 (were greatly reduced, which resulted in adverse regulation of protein processing and folding. Differential genes and proteins associated with a decline in energy metabolism and cell cycle arrest were also found in our study. However, use of RNAi to interfere with hemopoietic cell kinase (Hck) and EIF2AK2 transcriptions or use of chemical inhibitors of MAPK, p38, Ras, and JNK partially reversed the reduction of Gh1 levels induced by trichothecenes. It indicated that the activation of MAPKs, Hck, and EIF2AK2 were important for trichothecene-induced growth hormone suppression. Considering the potential hazards of exposure to trichothecenes, our findings could help to improve our understanding regarding human and animal health implications.

Natural Occurrence of Mycotoxins in Food and Feed: Pakistan Perspective

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

Serum cation profile of broilers at various stages of exposure to deoxynivalenol

The present experiment was carried out to investigate if levels of serum cations in broilers are modulated differently at various stages of exposure to deoxynivalenol (DON). Male broiler chicks at 7 days of age were fed a basal diet (0.27 mg of DON; 0.01 mg of zearalenone/kg), or either a low DON diet (1.68 mg of DON; 0.15 mg of zearalenone/kg) or a high DON diet (12.21 mg of DON; 1.09 mg of zearalenone/kg) produced using extracts from Fusarium graminearum cultures. Blood samples from the birds were collected during weeks 2, 4, and 5 of exposure. The high DON diet resulted in lower serum calcium levels compared to the basal diet at all the 3 sampling stages, while the low DON diet resulted in lower serum calcium levels only during weeks 2 and 5. Serum potassium levels were reduced under both the DON diets during weeks 2 and 5, while no diet-associated changes were found for serum levels of magnesium, sodium, and zinc. Under the present experimental conditions, the serum levels of calcium were consistently modulated in the broilers exposed to the DON-contaminated diets. The modulation of serum levels of potassium was, however, dependent upon the stage of exposure to DON.