Impact of deoxynivalenol on intestinal explants of broiler chickens: An ex vivo model to assess antimycotoxins additives

The impact of deoxynivalenol (DON) upon intestinal tissue of broilers was assessed by using jejunal explants in Ussing chambers and analyzing histopathological and immunohistochemical parameters; this system was also applied to evaluate the efficacy of an antimycotoxins additive (AMA). The explants were subjected to the following treatments within each experiment for 120 min: Experiment 1) T1 (control) - buffer solution, and T2 - 10 mg/L DON; and Experiment 2) T1 (control) - buffer solution, T2 - 10 mg/L DON, T3 - AMA (0.5%), and T4 - 10 mg/L DON + 0.5% AMA. In Experiment 1, DON triggered a reduction in the size of enterocytes as well as of their nuclei, an increase in cytoplasmic vacuolization and apical denudation of villi. Apoptotic cells count was also greater in DON-exposed explants. In Experiment 2, the AMA mitigated DON harmful effects; cytoplasmic vacuolization of enterocytes was reduced and the size of their nuclei was preserved. The additive also promoted a partial decrease in microvillus integrity, in size of enterocytes and in apoptotic cells count. The tested ex vivo model demonstrated the impact of DON upon the intestine as well as the efficacy of the AMA against its damaging effects.

Effects of Ochratoxin A exposure on DNA damage in porcine granulosa cells in vitro

Ochratoxin A (OTA), a feed mycotoxin, tends to impair the reproductive performance of animals. Our previous studies have demonstrated that OTA exposure inhibits porcine ovarian granulosa cell (GC) proliferation and induces their apoptosis, but the underlying toxic mechanism is still uncertain. In this study, we explored the OTA exposure on porcine GCs in vitro and found that OTA exposure inhibited the proliferation of porcine GCs and arrested cell cycle of GCs in the G2/M phase. The results based on RNA-Seq revealed that 20 μM and 40 μM OTA exposure increase DNA damage of porcine GCs in vitro. The differentially expressed genes (DEGs) of 40 μM OTA exposure were enriched in the pathways of mismatch repair, nucleotide excision repair and homologous recombination in DNA replication compared with control group and 20 μM OTA exposure group. Meanwhile, OTA exposure increased the expression levels of DNA double-strand breaks (DSBs) gene γ-H2AX, and DNA repair related genes, such as BRCA1, XRCC1, PARP1, and RAD51. Above all, our research revealed that OTA might exert deleterious effects on porcine ovarian GCs, influencing DNA repair-related biological processes and causing DNA damage response.

Deoxynivalenol and its metabolite deepoxy-deoxynivalenol: multi-parameter analysis for the evaluation of cytotoxicity and cellular effects

The mycotoxin deoxynivalenol (DON) contaminates agricultural commodities worldwide, posing health threats to humans and animals. Associated with DON are derivatives, such as deepoxy-deoxynivalenol (DOM-1), produced by enzymatic transformation of certain intestinal bacteria, which are naturally occurring or applied as feed additives. Using differentiated porcine intestinal epithelial cells (IPEC-J2), we provide the first multi-parameter comparative cytotoxicity analysis of DON and DOM-1, based on the parallel evaluation of lysosomal activity, total protein content, membrane integrity, mitochondrial metabolism and ATP synthesis. The study investigated the ability of DON and—for the first time of its metabolite DOM-1—to induce apoptosis, mitogen-activated protein kinase (MAPK) signalling, oxidative events and alterations of mitochondrial structure in porcine intestinal epithelial cells (IECs). The degree of DON toxicity strongly varied, depending on the cytotoxicity parameter evaluated. DON compromised viability according to the parameters of lysosomal activity, total protein content and membrane integrity, but increased viability according to assays based on mitochondrial metabolism and ATP synthesis. DON induced expression of cleaved caspase-3 (maximum induction 3.9-fold) and MAPK p38 and p42/p44 (maximum induction 2.51- and 2.30-fold, respectively). DON altered mitochondrial morphology, but did not increase intracellular ROS. DOM-1-treated IPEC-J2 remained unaffected at equimolar concentrations in all assays, thereby confirming the safety of feed additives using DON- to DOM-1-transforming bacteria. The study additionally highlights that an extensive multi-parameter analysis significantly contributes to the quality of in vitro data.

Cytotoxicity, apoptosis, DNA damage and methylation in mammary and kidney epithelial cell lines exposed to ochratoxin A

This study aimed to investigate the in vitro damage induced by ochratoxin A (OTA) in BME-UV1 and MDCK epithelial cells. Both cells lines were treated with OTA (0 up to 10 μg/mL), and cell viability (MTT assay), membrane stability (lactate dehydrogenase (LDH) release assay) and apoptotic cell rate (Tunel assay) were investigated. Further, the effect of the incubation with OTA has been evaluated at DNA level by the determination of DNA integrity, by the quantification of DNA adduct formation (8-hydroxy-2'-deoxyguanosine (8-OHdG)) and by the assessment of the global DNA methylation status (5-methyl-cytosine (5-mC)). The obtained results showed that after 24 h of OTA treatment, BME-UV1 cell viability was reduced in a dose-dependent way. OTA significantly (P < 0.05) increased LDH release in BME-UV1 cells at all concentrations tested. OTA (1.25 μg/mL) induced 35 % LDH release in MDCK cells (P < 0.05). A significant (P < 0.05) change in percentages of apoptotic BME-UV1 (10 ± 0.86) and MDCK (25 ± 0.88) cells was calculated when the cells were co-incubated with OTA. The level of 8-OHdG adduct formation was significantly (P < 0.05) increased in BME-UV1 cells treated with 1.25 μg/mL of OTA. The results of the present study suggest that a different mechanism of action may occur in these cell lines. Graphical abstract Study results overview.

Mycotoxin mechanisms of action and health impact: ‘in vitro’ or ‘in vivo’ tests, that is the question

The aim of this paper is to present examples of in vitro and in vivo tests for mycotoxin mechanisms of action and evaluation of health effects, with a focus on the gut environment and toxicity testing. In vivo investigations may provide information on the net effects of mycotoxins in whole animals, whereas in vitro models represent effective tools to perform simplified experiments under uniform and well-controlled conditions and a suitable alternative to in vivo animal testing providing insights not achievable with animal studies. The main limits of in vitro models are the lack of interactions with other cells and extracellular factors, lack of hormonal or immunological influences, and lack or different levels of in vitro expression of genes involved in the overall response to mycotoxins. The translation of in vitro data into meaningful in vivo effects remains an unsolved problem. The main issues to be considered are the mycotoxin concentration range in accordance with levels encountered in realistic situations, the identification of reliable biomarkers of mycotoxin toxicity, the measurement of the chronic toxicity, the evaluation of single- or multi-toxin challenge. The gastrointestinal wall is the first barrier preventing the entry of undesirable substances. The intestinal epithelium can be exposed to high concentrations of mycotoxins upon ingestion of contaminated food and the amount of mycotoxin consumed via food does not always reflect the amount available to exert toxic actions in a target organ. In vitro digestion models in combination with intestinal epithelial cells are powerful tools to screen and predict the in vivo bioavailability and digestibility of mycotoxins in contaminated food and correctly estimate health effects. In conclusion, in vitro and in vivo tests are complementary approaches for providing a more accurate picture of the health impact of mycotoxins and improved understanding and evaluation of relevant dietary exposure and risk scenarios.

Developments in mycotoxin analysis: an update for 2013-2014

This review highlights developments in the determination of mycotoxins over a period between mid-2013 and mid-2014. It continues in the format of the previous articles of this series, emphasising on analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone. The importance of proper sampling and sample preparation is briefly addressed in a dedicated section, while another chapter summarises new methods used to analyse botanicals and spices. As LC-MS/MS instruments are becoming more and more widespread in the determination of multiple classes of mycotoxins, another section is focusing on such newly developed multi-mycotoxin methods. While the wealth of published methods during the 12 month time span makes it impossible to cover every single one, this exhaustive review nevertheless aims to address and briefly discuss the most important developments and trends.