Dinotefuran induces BNIP3/NIX-mitophagy, necroptosis, and damage in the uterus of adolescent mice.

Xenobiotics such as pesticides can easily damage the reproductive organs during adolescence. Dinotefuran, the latest neonicotinoid insecticide, is considered to have low toxicity in vertebrates. However, research on its reproductive toxicity, especially damage to the female reproductive system in mammals is scarce. In this study, in vivo uterine toxicity was induced by oral administration of dinotefuran to mice at a dose ≥1/2 ADI (0.1 mg/kg/day), while in vitro toxicity was resulted from exposing cultured uteri to dinotefuran at levels equivalent to human blood levels (30-6000 ng/L). Hematoxylin-eosin staining revealed that dinotefuran caused uterine damage both in vivo and in vitro, while transmission electron microscopy detected mitophagy in the uterine cells. Furthermore, this study confirmed that dinotefuran triggered oxidative stress (decreased SOD and GSH, and elevated MDA), reduced mtDNA, and disrupted the BAX-to-BCL ratio in the uterus. Double immunofluorescence, qPCR, and western blot analyses found that dinotefuran induced excessive PRKN-independent mitophagy regulated by BNIP/NIX in the uterus, along with activation of NF-κB/NLRP3 signaling and the necroptosis pathway. It also revealed that dinotefuran increased uterine Caspase-1/Cleaved CASPASE-1 levels by qPCR and western blot analysis. Collectively, these findings indicate that dinotefuran at concentrations ≥1/2 ADI value or equivalent to human blood levels induces mouse uterine toxicity in vivo and in vitro, respectively, and they all trigger oxidative stress, BNIP3/NIX-mediated mitophagy, NF-κB/NLRP3 signaling, and necroptosis in the uterus.