Imidacloprid-Induced Ferroptosis-Associated Injury in Common Carp Hepatocytes: Potential Involvement of the miR-153c/SQSTM1 Axis

The neonicotinoid insecticide imidacloprid (IMD), widely used in agriculture, poses potential risks to aquatic ecosystems, yet its hepatotoxic mechanisms in freshwater fish remain poorly understood. This study investigates the roles of ferroptosis, mitochondrial dysfunction, inflammation, and the miR-153c/SQSTM1-mediated ferritinophagy pathway in IMD-induced hepatotoxicity in carp (Cyprinus carpio) hepatocytes. Using the CCK-8 assay, 0.6 μM IMD was selected for subsequent experiments. IMD exposure triggered ferroptosis, evidenced by increased intracellular Fe²⁺ accumulation, upregulated pro-ferroptotic gene and protein expression, and downregulated ferroptosis inhibitors (SLC7A11 and GPX4). Mitochondrial dysfunction was confirmed by reduced ATP content, decreased mtDNA levels, and a lowered NADPH/NADP⁺ ratio, along with aberrant expression of mitochondrial fission (Fis1 and Drp1) and fusion (Mfn1 and TFAM) genes. Additionally, IMD induced oxidative stress (elevated ROS and MDA; decreased T-AOC, CAT, and SOD activities) and a pronounced inflammatory response with upregulated pro-inflammatory cytokines. Mechanistically, IMD downregulated miR-153c, with concomitant upregulation of SQSTM1 at both the mRNA and protein levels, and dual-luciferase assays validated SQSTM1 as a direct target of miR-153c. miR-153c overexpression attenuated IMD-induced ferritinophagy, ferroptosis, and inflammation via the miR-153c/SQSTM1 axis. Collectively, these findings demonstrate that IMD induces hepatotoxicity in carp by triggering ferroptosis, mitochondrial dysfunction, and inflammation through the miR-153c/SQSTM1-mediated ferritinophagy pathway, providing mechanistic insights and potential targets for mitigating IMD’s ecological risks.