Quercetin alleviates DEHP exposure-induced pyroptosis and cytokine expression changes in grass carp L8824 cell line by inhibiting ROS/MAPK/NF-κB pathway

Bis(2-ethylhexyl) phthalate (DEHP) is not only a widely used plasticizer but also a common endocrine disruptor that frequently lingers in water, posing a threat to the health of aquatic organisms. Quercetin (Que) is a common flavonol found in the plant kingdom known for its antioxidant, anti-inflammatory, and immunomodulatory effects. However, it is still unclear whether DEHP can cause pyroptosis and affect the expression of cytokines of grass carp L8824 cells and whether Que has antagonistic effect in this process. In our study, grass carp L8824 cells were treated into four groups after 24 h, namely NC group, DEHP group (1000 μM DEHP), Que group (5 μM Que), and DEHP + Que group (1000 μM DEHP + 5 μM Que). Our results indicate a significant increase in the level of ROS in L8824 cells after exposure to DEHP. DEHP upregulated oxidative stress markers (H2O2 and MDA) and downregulated antioxidant markers (CAT, GSH, SOD, and T-AOC). DEHP also upregulated MAPK and NF-κB signal pathway-related proteins and mRNA expressions (p-p38, p-JNK, p-EPK, and p65). As for cell pyroptosis and its related pathways, DEHP upregulated pyroptosis-related protein and mRNA expressions (GSDMD, IL-1β, NLRP3, Caspase-1, LDH, pro-IL-18, IL-18, and ASC). Finally, DEHP can up-regulated cytokines (IL-6 and TNF-α) expression, down-regulated cytokines (IL-2 and IFN-γ) expression, and antimicrobial peptides (β-defensin, LEAP2, and HEPC). The co-treatment of L8824 cells with DEHP and Que inhibited the activation of the ROS/MAPK/NF-κB axis, alleviated pyroptosis, and restored expression of immune-related indicators. Finally, NAC was applied to reverse intervention of oxidative stress. In summary, Que inhibited DEHP-induced pyroptosis and the influence on cytokine and antimicrobial peptide expression in L8824 cells by regulating the ROS/MAPK/NF-κB pathway. Our results demonstrate the threat to fish health from DEHP exposure and confirmed the harm of DEHP to the aquatic ecological environment and the detoxification effect of Que to DEHP, which provides a theoretical basis for environmental toxicology.