Mitochondrial Function and Vitrification in Reproductive Cells

Mitochondria lie at the heart of gamete competence, supplying the adenosine triphosphate (ATP) required for meiotic progression, fertilisation and early embryo development. Their dynamic roles encompass regulation of calcium homeostasis, generation and detoxification of reactive oxygen species (ROS) and initiation of programmed cell death. Vitrification—an ultra‐rapid cooling method that transforms intracellular water into a glass‐like state—has revolutionised fertility preservation by avoiding ice‐crystal formation, yet it imposes substantial stress on mitochondrial architecture and function. Cryoprotective agents mitigate osmotic shock but may contribute to redox imbalances, membrane potential dissipation and calcium dysregulation. Compromised mitochondria yield elevated ROS, reduced ATP synthesis and altered signalling, all of which can impair fertilisation rates and embryo quality. Understanding and preserving mitochondrial integrity during vitrification are thus central to improving assisted‐reproductive technologies, with implications for human IVF, oncofertility and the conservation of endangered species.

Research from Nature Portfolio

One foundational study demonstrated that L-proline acts both as a natural osmoprotectant and an antioxidant during mouse oocyte vitrification. Supplementation with L-proline markedly improved post‐thaw survival, maintained mitochondrial membrane potential and preserved ATP levels, underscoring its dual role in osmotic balance and redox buffering.

Another investigation addressed calcium‐mediated mitochondrial damage in vitrified bovine oocytes. By applying the cytoplasmic Ca2+ chelator BAPTA-AM and the mitochondrial Ca2+ flux inhibitor ruthenium red, researchers prevented endoplasmic reticulum release and mitochondrial calcium overload. Treated oocytes exhibited normal mitochondrial membrane potential, restored ATP content, reduced apoptosis and improved rates of fertilisation and embryo development.

Mitochondrial Function and Vitrification in Reproductive Cells publication trend

The graph below shows the total number of articles in mitochondrial function and vitrification in reproductive cells across all publications each year (not limited to Nature Index journals).

Technical terms

Vitrification: An ultra‐rapid cryopreservation technique that solidifies intracellular fluids into an amorphous glass, preventing ice‐crystal formation.

Cryoprotectant: A chemical agent, such as ethylene glycol or L-proline, used to reduce ice formation, osmotic stress and cellular dehydration during freezing.

Reactive oxygen species (ROS): Chemically reactive molecules derived from oxygen (e.g. superoxide, hydrogen peroxide) that can damage lipids, proteins and DNA if not neutralised.

Mitochondrial membrane potential: The electrochemical gradient across the inner mitochondrial membrane essential for ATP synthesis via oxidative phosphorylation.

Metaphase II (MII) oocyte: A mature egg cell arrested at the second meiotic division, optimally poised for fertilisation and highly sensitive to cryopreservation stress.

Histone lactylation: A post‐translational modification in which lactate-derived groups are appended to histone lysine residues, influencing chromatin structure and gene expression.

References

1. L-proline: a highly effective cryoprotectant for mouse oocyte vitrification. Scientific Reports (2016).
2. Calcium ion regulation by BAPTA-AM and ruthenium red improved the fertilisation capacity and developmental ability of vitrified bovine oocytes. Scientific Reports (2017).
3. The walnut-derived peptide TW-7 improves mouse parthenogenetic embryo development of vitrified MII oocytes potentially by promoting histone lactylation. Journal of Animal Science and Biotechnology (2024).
4. Superior performance of biocomposite nanoparticles PLGA-RES in protecting oocytes against vitrification stimuli. Frontiers in Bioengineering and Biotechnology (2024).
5. Oxidative Stress and Oocyte Cryopreservation: Recent Advances in Mitigation Strategies Involving Antioxidants. Cells (2022).