Atractylenolide III partially alleviates tunicamycin-induced damage in porcine oocytes during in vitro maturation by reducing oxidative stress

Assisted reproductive technology (ART) is widely used to address infertility and enhance reproductive outcomes in livestock. Among various ART techniques, in vitro maturation (IVM) is commonly used to obtain high-quality oocytes but is susceptible to oxidative stress. In traditional Chinese medicine, Rhizoma Atractylodis Macrocephalae (Bai Zhu) is used to enhance maternal and fetal health. Atractylenolide III (AIII), a major component of Bai Zhu, has shown both antioxidant properties and oxidative stress induction, leading to controversy. This study used porcine oocytes as a model to investigate the effects of AIII under tunicamycin (TM)-induced oxidative stress. During IVM, oocytes were treated with various concentrations of AIII and a constant dose of TM. AIII promoted oocyte maturation and cumulus cell expansion, with the optimal concentration being 1 mg/L. AIII reduced reactive oxygen species (ROS) and malondialdehyde (MDA) levels, indicating reduced oxidative damage. Mitochondrial function and membrane potential (MMP) were preserved in AIII-treated oocytes. Additionally, AIII could alleviate TM-induced endoplasmic reticulum (ER) stress, as shown by decreased mRNA expression of ER stress markers. Following parthenogenetic activation (PA), AIII-treated oocytes exhibited increased cleavage and blastocyst formation rates with reduced apoptosis compared to the TM group. These findings suggest that AIII protects against oxidative stress, improving oocyte quality and developmental potential, with potential applications in ART.