POPC Enhances Both the Maturation of Bovine Oocytes and the Subsequent Development and Quality of Embryos

TL;DR

Adding POPC to bovine oocyte culture improves maturation and embryo quality by reducing stress and boosting cell health.

Contribution

This study identifies POPC as a novel supplement that enhances bovine oocyte maturation and embryo development through antioxidant and anti-apoptotic mechanisms.

Findings

150 μmol/mL POPC significantly increased polar body extrusion and embryo cleavage rates.

POPC reduced ROS levels, improved mitochondrial activity, and enhanced spindle integrity in oocytes.

Transcriptomic analysis revealed POPC's activation of SIRT1/2 and suppression of apoptosis-related genes.

Abstract

In vitro maturation (IVM) of oocytes is a critical step in livestock-assisted reproductive technologies. However, oxidative stress and mitochondrial dysfunction under in vitro conditions readily induce bovine oocyte aging, thereby limiting the efficiency of IVM. This study investigated the regulatory effects of palmitoyloleoylphosphatidylcholine (POPC) on IVM, oocyte aging, and developmental competence in bovine oocytes. Cumulus–oocyte complexes (COCs) were collected from slaughterhouse-derived ovaries and assigned to control (0 μmol/mL) and experimental groups supplemented with 50–200 μmol/mL of POPC. Following 22 h of culture at 38.5 °C under 5% CO2, the optimal concentration was determined through comprehensive analysis. Results demonstrated that 150 μmol/mL of POPC was the most effective treatment, significantly increasing the first polar body extrusion rate and cleavage rate of 2- to 4-cell embryos. This concentration effectively reduced reactive oxygen species (ROS) levels, elevated glutathione (GSH) content, and improved mitochondrial activity and spindle integrity. Furthermore, POPC modulated key molecular pathways by up-regulating SIRT1/2 and BCL-2 expression while down-regulating BAX and Caspase-1/3 activation, suggesting suppression of apoptosis and enhanced cellular resilience. These findings provide a mechanistic basis for optimizing livestock-assisted reproductive technologies through targeted lipid supplementation.

In vitro maturation (IVM) of oocytes is a pivotal step in assisted reproductive technologies for livestock. However, oxidative stress (OS) and mitochondrial dysfunction during in vitro culture often lead to oocyte aging, thereby limiting the efficiency of the technologies. To address these challenges, this study investigated the regulatory effects of 1-Palmitoyl-2-Oleoyl-sn-Glycero-3-Phosphocholine (POPC) on bovine oocyte IVM, aging, and developmental competence to determine the optimal concentration and explore underlying mechanisms. Cumulus–oocyte complexes (COCs) were collected from abattoir-derived bovine ovaries and cultured in IVM medium supplemented with 0 (control), 50, 100, 150, or 200 μmol/mL of POPC (n = 300 per group) at 38.5 °C under 5% CO2 for 22 h. The optimal concentration was determined based on the first polar body extrusion rate, followed by in vitro fertilization (IVF), fluorescence staining, Smart-seq2 transcriptome sequencing, and quantitative PCR (qPCR) analysis. The results demonstrated that 150 μmol/mL of POPC yielded the highest maturation rate, significantly exceeding the control group (p < 0.05), and enhanced 2-4-cell cleavage rates after IVF. Furthermore, POPC markedly reduced intracellular reactive oxygen species (ROS) levels, increased glutathione (GSH) content, improved mitochondrial function, and restored normal spindle morphology. Transcriptomic analysis identified 350 upregulated and 280 downregulated differentially expressed genes (DEGs), which were enriched in pathways related to OS. qPCR validation confirmed upregulation of SIRT1/2 and BCL-2, along with downregulation of BAX and Caspase-1/3. Collectively, these findings suggest that 150 μmol/mL of POPC alleviates OS and activates the “SIRT–antioxidant–antiapoptotic” signaling axis, thereby providing valuable insights for optimizing assisted reproductive technologies in livestock.

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