Effects of Liposome-Encapsulated α-Pinene on In Vitro Oocyte Maturation and Embryo Development in Bovine Species

Oocyte in vitro maturation (IVM) represents a crucial phase in embryo production, often compromised by reactive oxygen species (ROS). Strategies to mitigate ROS are essential to improve oocyte quality. This study investigated the effects of liposome-encapsulated α-pinene (Lip-α-pinene) on bovine oocyte IVM and embryonic development following parthenogenetic activation. Cumulus-oocyte complexes (COCs) were matured in vitro for 22-24 h in control medium or supplemented with Lip-blank, or 0.01, 1.0 or 100.0 µg/mL Lip-α-pinene. Lip-α-pinene had a size of 75.86 ± 0.95 nm, low polydispersity (0.26 ± 0.00), and zeta potential of -31.55 ± 2.23 mV. Nuclear maturation was not affected. However, COCs matured with 1.0 µg/mL Lip-α-pinene showed well-preserved ultrastructure of oocyte and cumulus cells, reduced ROS levels and lipid accumulation compared to control, Lip-blank, and 100.0 µg/mL Lip-α-pinene. This was accompanied by relative abundance of NRF2, SOD, and PRDX6. Furthermore, 1.0 and 100.0 µg/mL Lip-α-pinene increased cleavage rates and cells per blastocyst compared to control, while blastocyst rates and lipid content were not affected. In conclusion, 1.0 µg/mL Lip-α-pinene enhances antioxidant capacity of bovine oocytes by reducing ROS and lipid accumulation, associated with abundance of NRF2, SOD, and PRDX6 transcripts, thereby improving oocyte competence and quality of parthenogenetic embryos.