Steroidogenic differential effects in neonatal porcine Leydig cells exposed to persistent organic pollutants derived from cod liver oil

Comparative Cytotoxic Effects and Possible Mechanisms of Deoxynivalenol, Zearalenone and T-2 Toxin Exposure to Porcine Leydig Cells In Vitro

Mycotoxins such as zearalenone (ZEN), deoxynivalenol (DON) and T-2 toxin (T-2) are the most poisonous biological toxins in food pollution. Mycotoxin contaminations are a global health issue. The aim of the current study was to use porcine Leydig cells as a model to explore the toxic effects and underlying mechanisms of ZEN, DON and T-2. The 50% inhibitory concentration (IC50) of ZEN was 49.71 μM, and the IC50 values of DON and T-2 were 2.49 μM and 97.18 nM, respectively. Based on the values of IC50, ZEN, DON and T-2 exposure resulted in increased cell apoptosis, as well as disrupted mitochondria membrane potential and cell cycle distribution. The results also showed that ZEN and DON significantly reduced testosterone and progesterone secretion in Leydig cells, but T-2 only reduced testosterone secretion. Furthermore, the expression of steroidogenic acute regulatory (StAR) protein and 3β-hydroxysteroid dehydrogenase (3β-HSD) were significantly decreased by ZEN, DON and T-2; whereas the protein expression of cholesterol side-chain cleavage enzyme (CYP11A1) was only significantly decreased by ZEN. Altogether, these data suggest that the ZEN, DON and T-2 toxins resulted in reproductive toxicity involving the inhibition of steroidogenesis and cell proliferation, which contributes to the cellular apoptosis induced by mitochondrial injury in porcine Leydig cells.

The design of an environmentally relevant mixture of persistent organic pollutants for use in in vivo and in vitro studies

Amongst the substances listed as persistent organic pollutants (POP) under the Stockholm Convention on Persistent Organic Pollutants (SCPOP) are chlorinated, brominated, and fluorinated compounds. Most experimental studies investigating effects of POP employ single compounds. Studies focusing on effects of POP mixtures are limited, and often conducted using extracts from collected specimens. Confounding effects of unmeasured substances in such extracts may bias the estimates of presumed causal relationships being examined. The aim of this investigation was to design a model of an environmentally relevant mixture of POP for use in experimental studies, containing 29 different chlorinated, brominated, and perfluorinated compounds. POP listed under the SCPOP and reported to occur at the highest levels in Scandinavian food, blood, or breast milk prior to 2012 were selected, and two different mixtures representing varying exposure scenarios constructed. The in vivo mixture contained POP concentrations based upon human estimated daily intakes (EDIs), whereas the in vitro mixture was based upon levels in human blood. In addition to total in vitro mixture, 6 submixtures containing the same concentration of chlorinated + brominated, chlorinated + perfluorinated, brominated + perfluorinated, or chlorinated, brominated or perfluorinated compounds only were constructed. Using submixtures enables investigating the effect of adding or removing one or more chemical groups. Concentrations of compounds included in feed and in vitro mixtures were verified by chemical analysis. It is suggested that this method may be utilized to construct realistic mixtures of environmental contaminants for toxicity studies based upon the relative levels of POP to which individuals are exposed.