Protective effect of glutamine and alanyl-glutamine against zearalenone-induced intestinal epithelial barrier dysfunction in IPEC-J2 cells.

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin, has a negative effect on porcine intestine. Glutamine (Gln) and alanyl-glutamine (Ala-Gln) are nutrients with potential preservation functions similar to those of the intestinal epithelial barrier. The protective role of Gln and Ala-Gln on ZEN-induced intestinal barrier dysfunction was evaluated in this study. Additionally, the ability of Gln and Ala-Gln to protect the intestinal barrier was investigated. Our results showed that lactate dehydrogenase (LDH) activity, paracellular permeability and reactive oxygen species (ROS) level were increased by ZEN, while the glutathione (GSH) level was decreased by ZEN. Gln and Ala-Gln promoted the proliferation of cells and attenuated the ZEN-induced increase in cytotoxicity, cell apoptosis and paracellular permeability. Gln and Ala-Gln alleviated barrier function damage, which was additionally induced by ZEN by increasing the antioxidant capacity of cells. In addition, Gln and Ala-Gln upregulated intestinal barrier associated gene expressions including pBD-1, pBD-2, MUC-2, ZO-1, occludin and claudin-3. This study revealed that Gln and Ala-Gln had similar effects in protecting intestinal epithelial barrier function against ZEN exposure in IPEC-J2 cells. A new treatment for alleviating ZEN-induced injury to the intestine through nutritional intervention is provided.