Cr(VI) and DON co-exposure triggers intestinal epithelial cells ferroptosis and pyroptosis through Nrf2/NF-κB/NLRP3 to impair intestinal barrier function

Objectives Cr(VI) and DON are natural co-occurring pollutants in the environment. This study aimed to investigate the molecular mechanisms underlying oxidative damage to the intestinal barrier and intestinal epithelial cell (IECs) toxicity induced by Cr(VI) and DON.Methods The target genes and signaling pathways were predicted using the network toxicology method. This was verified through cell intervention experiments with Nrf2 activator TBHQ, NF-κB inhibitor PDTC, and NLRP3 inhibitor MCC950.Results Cr(VI) and/or DON aggravated inflammatory infiltration in the intestine, disrupted tight junction structures. Network toxicology revealed that ferroptosis and pyroptosis pathways are involved in regulating oxidative damage and barrier dysfunction in primary small IECs in broilers. Cr(VI) and/or DON induced oxidative stress and inhibited Nrf2 expression. They abnormally activated the NF-κB/NLRP3 pathway in IECs, thereby triggering ferroptosis and pyroptosis, and exacerbating oxidative damage to the intestinal barrier. Overexpression of Nrf2 and silencing of NLRP3/NF-κB could bidirectionally reverse oxidative stress, iron accumulation, inflammatory factor secretion and intestinal barrier dysfunction in IECs, inhibit the progression of ferroptosis and pyroptosis.Conclusion The cross-regulation of ferroptosis and pyroptosis mediated by the bidirectional imbalance of the Nrf2/NF‑κB/NLRP3 axis constitutes the core molecular mechanism underlying intestinal epithelial barrier dysfunction and oxidative damage induced by co-exposure to Cr(VI) and DON.