The Antagonistic Effect of Glutamine on Zearalenone-Induced Apoptosis via PI3K/Akt Signaling Pathway in IPEC-J2 Cells

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.