Growth Disturbance, Neurotoxicity, and Inflammatory Immune Response of Sulfoxaflor in <i>Xenopus laevis</i> Tadpoles: New Perspective from Pesticide Exposure to Elimination

As an alternative to traditional pesticides, sulfoxaflor (SFX) is a sulfoximine insecticide with the same mechanism of action as neonicotinoid insecticides (NNIs). However, increasing evidence suggests that SFX poses a threat to aquatic organisms. To investigate the toxic effects and potential risks in amphibians, bioaccumulation and elimination experiments were conducted at environmentally relevant concentrations. The results indicate that although SFX exhibits low acute toxicity and accumulation, it demonstrates neurotoxicity and endocrine-disruptive properties. SFX alters regulatory patterns of growth-related genes and interferes with the regulation of thyroid hormones and its genes, promoting the tadpoles' growth. Additionally, SFX induces oxidative stress, leading to inflammation and immune regulation in the tadpoles. It also affects neurotransmitter transmission as well as the genes associated with neural synapses, receptor, and signal transmission and interferes with tadpole behavior. These toxic effects persisted until the elimination stage. Compared with other NNIs, SFX has the most binding sites with AChR and a weak interaction, and binding to β-agonists is similar in molecular docking. Risk assessment suggests that SFX has a potential risk and impact on aquatic amphibians, which may be underestimated. The result provides valuable reference and new perspective for the ecological safety assessment and supervision of SFX, NNIs, and insecticides of low acute toxicity.