A Novel Antifreeze Peptide Inhibits Intrinsic Mitochondrial Apoptosis in Bovine Embryos During Vitrification

Abstract

The vitrification of embryos is essential for animal reproduction and significantly contributes to assisted reproductive technologies, enabling fast cryopreservation without ice crystal formation. Mitochondria, vital organelles in cellular metabolism, are responsible for critical functions like ATP synthesis, calcium regulation, and apoptotic signaling. Preserving mitochondrial integrity is essential for ensuring embryonic strength. Studies demonstrate that vitrification, a widely used cryopreservation method, can markedly impair mitochondrial function in mammalian embryos. This study examines the efficacy of novel/modified antifreeze peptide as a biocompatible agent when used in an appropriate concentration with base vitrification media. Blastocysts vitrified in base media as well as supplemented with the peptide exhibited significantly enhanced post-thaw survival rates, attaining re-expansion and hatching rates of 96.89 ± 4.2% and 88.31 ± 1.3%, respectively, in contrast to 79.38 ± 3.7% and 52.57.9 ± 0.8% observed in the control group. Furthermore, peptide-treated BLs demonstrated elevated expression of PGC1α, BCL2, and Sirt-1, which are the key genes related to mitochondrial membrane potential and anti-apoptotic factors. The mitochondrial function was maintained, and the levels of reactive oxygen species (ROS) and the expression of genes such as Cyto-c, caspases 3, and caspase 9 were markedly diminished in the embryos vitrified with peptide. These findings highlight the ability of this modified peptide to preserve mitochondrial integrity and reduce oxidative stress, hence enhancing the survival of blastocysts post-vitrification.