Effect of VA/RA on Oxidative Damage Induced by Hydrogen Peroxide in Primary Duck Intestinal Epithelial Cells

Background: Vitamin A (VA) is an essential fat-soluble vitamin that contributes to the normal metabolism of intestinal epithelial cells (IEC), fights infections and enhances immunity. Retinoic acid (RA) is the physiological metabolite of VA, which is increased under oxidative stress and has an important physiological function. We studied the protective mechanism of VA/RA in H 2 O 2 -induced oxidative stress in primary duck IECs. Cells were distributed into 5 groups: blank control group (CG1), positive control group (CG2), high concentration retinoic acid group (TG1) (VA:RA=1 × 10 -8 M:3 × 10 -8 M), equal concentration retinoic acid group (TG2) (VA:RA=2 × 10 -8 M:2 × 10 -8 M), and low concentration retinoic acid group (TG3) (VA:RA=3 × 10 -8 M:1 × 10 -8 M). The blank control group had no treatment, and the positive control group and the treatment groups were all treated with 50 μM H 2 O 2 to induce oxidative stress. Each group had 3 replicates. RNA-Seq was used to screen differentially expressed genes, KEGG functional annotation and GO analysis were performed and the results were verified by qRT-PCR. The cell viability was quantified by the CCK-8 assay. Intestinal barrier integrity and tight junction permeability were measured by transepithelial electrical resistance (TEER). Results: : An RNA-Seq analysis showed that treatment with VA/RA altered the expression of genes involved in the cell adhesion, immune response, metabolism and cell regulation. Our results suggest that abnormal the PPARγ expression may be involved in H 2 O 2 -induced oxidative stress and in the therapeutic mechanism of VA/RA treatment. Treatment with 50 μM H 2 O 2 significantly decreased live cell numbers compared with those in CG1. Compared with those in CG2, the cell viability and TEER in the TGs were significantly improved (P < 0.05). As the RA concentration increased, the relative expression of Nrf2 and HO-1 increased (P < 0.05). The TGs had higher expression levels of ZO-1, claudin-1 and Occludin than CG2 (P < 0.05). Conclusions: : VA and its derivative RA relieve intestinal epithelial barrier dysfunction induced by H 2 O 2 , the PPAR and Nrf2/HO-1 signaling pathway may participate these proses.