Chlorantraniliprole induces mitophagy, ferroptosis, and cytokine homeostasis imbalance in grass carp (Ctenopharyngodon idella) hepatocytes via the mtROS-mitochondrial fission/fusion axis

Chlorantraniliprole (CAP) is a bis-amide pesticide used for pest control mainly in agricultural production activities and rice-fish co-culture systems. CAP residues cause liver damage in non-target organism freshwater fish. However, it is unclear whether CAP-exposure-induced liver injury in fish is associated with mitochondrial dysfunction-mediated mitophagy, ferroptosis, and cytokines. Therefore, we established grass carp hepatocyte models exposed to different concentrations of CAP (20, 40, and 80 μM) in vitro. MitoSOX probe, JC-1 staining, immunofluorescence double staining, Fe2+ staining, lipid peroxidation staining, qRT-PCR, and Western blot were used to verify the physiological regulatory mechanism of CAP induced liver injury. In the present study, the CAP-treated groups exhibited down-regulation of antioxidant-related enzyme activities and accumulation of peroxides. CAP treatment induced an increase in mitochondrial reactive oxygen species (mtROS) levels and altered expression of mitochondrial fission/fusion (Drp1, Fis1, Mfn1, Mfn2, and Opa1) genes in grass carp hepatocytes. In addition, mitophagy (Parkin, Pink1, p62, LC3II/I, and Beclin-1), ferroptosis (GPX4, COX2, ACSL4, FTH, and NCOA4), and cytokine (IFN-γ, IL-18, IL-17, IL-6, IL-10, IL-1β, IL-2, and TNF-α)-related gene expression was significantly altered. Collectively, these findings suggest that CAP exposure drives mitophagy activation, ferroptosis occurrence, and cytokine homeostasis imbalance in grass carp hepatocytes by triggering mitochondrial dysfunction mediated by the mtROS-mitochondrial fission/fusion axis. This study partly explained the physiological regulation mechanism of grass carp hepatocyte injury induced by insecticide CAP from the physiological and biochemical point of view and provided a basis for evaluating the safety of CAP environmental residues to non-target organisms.