N-Acetyl-L-Cysteine Promotes Porcine Oocyte In Vitro Maturation and Subsequent Embryonic Development by Regulating Oxidative Stress

Abstract

Simple Summary The in vitro production of porcine embryos is important for animal breeding, reproductive research, and the preservation of valuable genetic resources. However, porcine oocytes are susceptible to damage from excessive reactive oxygen species (ROS) during in vitro maturation (IVM). This study evaluated whether N-acetyl-L-cysteine (NAC), a potent antioxidant, could protect porcine oocytes and improve their subsequent embryonic developmental competence. Among the concentrations tested, 1.5 mM NAC improved oocyte maturation, reduced oxidative damage, and enhanced the function of mitochondria, the cellular structures responsible for energy production. This treatment also increased the cleavage rate and blastocyst formation after fertilization and enhanced the cleavage rate after parthenogenetic activation (PA). However, this treatment did not significantly affect oocyte survival rate or ROS levels following vitrification–warming. Single-cell transcriptomic analysis revealed that the differentially expressed genes (DEGs) were mainly enriched in the oxidative phosphorylation (OXPHOS) pathway. These findings may help improve IVM methods for producing porcine embryos and support future advances in animal breeding and reproductive biotechnology.