Zearalenone (ZEN), a nonsteroidal estrogen mycotoxin, is widely found in feed and foodstuffs. Intestinal cells may become the primary target of toxin attack after ingesting food containing ZEN. Porcine small intestinal epithelial (SIEC02) cells were selected to assess the effect of ZEN exposure on the intestine. Cells were exposed to ZEN (20 µg/mL) or pretreated with (81, 162, and 324 µg/mL) N-acetylcysteine (NAC) prior to ZEN treatment. Results indicated that the activities of glutathione peroxidase (Gpx) and glutathione reductase (GR) were reduced by ZEN, which induced reactive oxygen species (ROS) and malondialdehyde (MDA) production. Moreover, these activities increased apoptosis and mitochondrial membrane potential (ΔΨm), and regulated the messenger RNA (mRNA) expression of Bax, Bcl-2, caspase-3, caspase-9, and cytochrome c (cyto c). Additionally, NAC pretreatment reduced the oxidative damage and inhibited the apoptosis induced by ZEN. It can be concluded that ZEN-induced oxidative stress and damage may further induce mitochondrial apoptosis, and pretreatment of NAC can degrade this damage to some extent.

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Zearalenone (ZEN) is a widespread contaminant of cereals and agricultural products which causes food safety issues. Ingesting food or feed contaminated with ZEN can disrupt the intestinal epithelial barrier function. The RhoA/ROCK signaling pathway plays a key role in regulating the epithelial barrier function, but studies on such roles have rarely focused on the intestine. The aim of this experiment was to investigate the exact mechanism of ZEN-induced intestinal barrier damage and whether the RhoA/ROCK signaling pathway is involved. The results showed that ZEN significantly induced alkaline phosphatase (AP) activity and FITC–dextran (4 kDa) passage across the epithelial barrier, which significantly reduced the transepithelial resistance (TEER). Meanwhile, ZEN could induce the significantly down-regulated mRNA expression of tight junction proteins (occludin, claudin-1, ZO-1, and claudin-3) and redistribution of ZO-1 immunofluorescence. Further studies demonstrated that ZEN exposure activated the RhoA/ROCK signaling pathway, significantly up-regulated the mRNA expression of ROCK1, the main effector of the signaling pathway, the protein expression of phosphorylated myosin light chain (MLC) and myosin light chain kinase (MLCK), and relatively increased the activity of ATP in cells, simultaneously remodeling the cytoskeleton (F-actin). Overall, our study indicated that ZEN induced intestinal barrier dysfunction by activating the RhoA/ROCK signaling pathway.

Zearalenone (ZEN) is a non-steroidal estrogen mycotoxin produced by Fusarium fungi, which inevitably exists in human and animal food or feed. Previous studies indicated that apoptosis seems to be a key determinant of ZEN-induced toxicity. This experiment aimed to investigate the protective effects of Glutamine (Gln) on ZEN-induced cytotoxicity in IPEC-J2 cells. The experimental results showed that Gln was able to alleviate the decline of cell viability and reduce the production of reactive oxygen species and calcium (Ca2+) induced by ZEN. Meanwhile, the mRNA expression of antioxidant enzymes such as glutathione reductase, glutathione peroxidase, and catalase was up-regulated after Gln addition. Subsequently, Gln supplementation resulted in the nuclear fission and Bad-fluorescence distribution of apoptotic cells were weakened, and the mRNA expression and protein expression of pro-apoptotic genes and apoptotic rates were significantly reduced. Moreover, ZEN reduced the phosphorylation Akt, decreased the expression of Bcl-2, and increased the expression of Bax. Gln alleviated the above changes induced by ZEN and the antagonistic effects of Gln were disturbed by PI3K inhibitor (LY294002). To conclude, this study revealed that Gln exhibited significant protective effects on ZEN-induced apoptosis, and this effect may be attributed to the PI3K/Akt signaling pathway.