Effect of cypermethrin on thyroid follicular epithelial cell injury via the ROS-NF-κB-NLRP3 pathway

Cypermethrin (CYP, IUPAC name: [cyano-(3-phenoxyphenyl)methyl] 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate), a type II pyrethroid insecticide, is suggested to have potential adverse effects on human endocrine, immune, and neurotoxic systems. Objectives: In this study, we aimed to investigate whether CYP causes oxidative stress and pyroptosis in thyroid follicle epithelial cells through the activation of the ROS-NFκB-NLRP3 pathway, thereby causing inflammatory responses. Methods: Nthy-ori 3-1 cells were used as an in vitro model and exposed to CYP at different doses (0, 100, 200, 400, 800, and 1600 μmol/L) for 24   h. Results: CYP treatment enhanced oxidative damage in Nthy-ori 3-1 cells, characterized by cellular crumpling, indistinct borders, increased cellular gaps, appearance of intercellular grease droplets, and increased pyroptosis. Subsequent treatment with the caspase-1 inhibitor VX-765 enhanced cell viability in the VX-765+CYP group, improving cell morphology, reducing pyroptotic vesicles, suppressing oxidative stress, and downregulating Interleukin-18(IL-18) (an inflammatory factor) level. Conclusion: The results demonstrate that CYP induces pyroptosis in Nthy-ori 3-1 cells through activation of the reactive oxygen species (ROS)-NF-κB-NLRP3 pathway.