Lycopene improves the developmental competence of vitrified-thawed oocytes by reestablishing redox balance and modulating Rock1 expression.

Purpose: Oocyte vitrification is a critical technique for female fertility preservation; however, it is often accompanied by cryodamage that compromises subsequent embryo development. Moreover, limited research has assessed the long-term effects on offspring derived from vitrified oocytes. While antioxidants are frequently used to mitigate vitrification-induced oxidative stress and have been shown to enhance embryo development, their impact on implantation and offspring outcomes remains underexplored. Lycopene (LYC), a potent natural antioxidant, has not yet been evaluated in the context of oocyte vitrification.

Methods: Oocytes were collected from 4-week-old C57/BL6J female mice. Fresh oocytes served as the negative control (n = 393). Vitrified-thawed oocytes were cultured in post-warming, IVF, and embryo culture media supplemented with 0 µM (positive control, n = 479), 0.05 µM (n = 485), 0.1 µM (n = 499), or 0.2 µM (n = 461) lycopene. Blastocysts from the fresh, vitrified, and LYC-0.1µM groups were transferred into the uterine horns of 3.5-dpc pseudopregnant 8-week-old ICR female mice to assess in vivo development.

Results: Supplementation with 0.1 µM lycopene significantly improved the blastocyst formation rate in vitrified oocytes (75.56 ± 8.69% vs. 66.53 ± 6.94%, P = 0.029). Lycopene treatment elevated intracellular glutathione (GSH) levels (P < 0.001) and reduced reactive oxygen species (ROS) levels (P = 0.014). Notably, 0.1 µM lycopene modulated Rock1 expression during early embryogenesis, especially at the 4-cell stage, suggesting a potential role in developmental regulation. Despite improved preimplantation development, live birth rates following embryo transfer were similar between vitrified groups with or without lycopene, and both remained significantly lower than the fresh group (P = 0.008). None of the offspring had any apparent birth defect. No significant differences were observed among offspring in birth weight, growth trajectory, major organ morphology, gonadosomatic indices, or follicles counting among offspring.

Conclusions: Lycopene exerts a protective effect against vitrification-induced oxidative stress by restoring redox homeostasis within oocytes and modulating Rock1 expression during early embryo development. Importantly, lycopene treatment did not compromise offspring health, supporting its potential as a safe adjunct to improve vitrification outcomes.