Dimefluthrin-induced multigenerational endocrine toxicity in zebrafish (Danio rerio) offspring via parental exposure

The widespread use of household insecticides has been potentially linked to an increase in human health issues such as respiratory irritation, neurotoxicity, and endocrine disruption, raising significant concerns about their potential risks. Dimefluthrin demonstrates significant insecticidal efficacy against public health pests such as mosquitoes, flies, cockroaches, and bed bugs, and is widely applied in the field of public health. Long-term low-dose exposure of zebrafish to dimefluthrin resulted in apparent toxic effects in adults, including abnormal condition factors, gonadal structural damage, and abnormal mating behavior. Further investigation into the multigenerational toxicity of dimefluthrin in zebrafish revealed decreased embryo quality (reductions in spawning amount, fertilization rate, hatching rate, and survival rate) and pronounced endocrine-disrupting effects in the offspring. Specifically, multiple endocrine-disrupting effects were observed in the HPT, HPA, and HPG axes: HPT axis dysfunction was associated with dysregulated T4 metabolism; HPA axis impairment was related to abnormal secretion of ACTH and COR; and HPG axis reproductive dysfunction was linked to abnormal secretion of E2 and T, as well as disruption of the E2 synthesis pathway. Furthermore, female adult zebrafish exposed alone to 0.5 μg/L dimefluthrin exhibited stronger multigenerational toxicity than male adult zebrafish exposed alone.