Alpha-Tocopherol Protects Porcine Oocytes from Acetamiprid-Induced Meiotic Defects by Alleviating Oxidative Stress-Mediated Ferroptosis.

Acetamiprid (ACE), a widely used neonicotinoid insecticide, has raised concerns due to its potential reproductive toxicity. While its adverse effects on animal reproductive systems have been documented, the impact of ACE on mammalian oocytes remains poorly understood. This study aimed to investigate the potential effects of ACE exposure on porcine oocytes and evaluate whether alpha-tocopherol (α-TOC), a fat-soluble antioxidant, could alleviate ACE-induced oocyte damage. Porcine cumulus oocyte complexes (COCs) were exposed to ACE alone or co-treated with α-TOC for 44 h during in vitro maturation. ACE exposure significantly reduced the first polar body (PB1) excretion rate, arrested meiotic progression, and disrupted spindle assembly in porcine oocytes. Furthermore, ACE impaired mitochondrial function, evidenced by decreased mitochondrial membrane potential (MMP), while increasing intracellular reactive oxygen species (ROS) accumulation and lipid peroxidation (LPO). Additionally, ACE exposure induced intracellular iron overload and dysregulated ferroptosis-related genes, downregulating solute carrier family 7 member 11 (SLC7a11) and glutathione peroxidase 4 (GPX4) while upregulating transferrin receptor 1 (TfRC) and acyl-CoA synthetase long-chain family member 4 (ACSL4), contributing to the occurrence of oocyte ferroptosis. Notably, α-TOC co-treatment effectively alleviate oxidative stress and lipid peroxidation, thereby protecting oocytes from ACE-induced ferroptosis. Collectively, these findings indicate that oxidative stress-mediated ferroptosis may be a major contributing pathway through which ACE impairs oocyte maturation and suggest that α-tocopherol may serve as a protective agent against ACE-induced oocyte damage.