Research report: Carnosine enhances mouse oocyte vitrification outcomes with associated redox and transcriptional changes

The findings, reported in a peer-reviewed accepted article shared ahead of final editing, suggest that carnosine may help counteract the oxidative stress and mitochondrial dysfunction associated with oocyte cryopreservation, a technique widely used for fertility preservation.

In the study, metaphase II mouse oocytes were vitrified and warmed in the presence of either 100 or 500 micromolar carnosine, or without the additive, and then fertilized by intracytoplasmic sperm injection and cultured. Fresh oocytes served as additional controls. Both carnosine concentrations significantly restored two-cell formation rates, which reached 80 and 81 percent compared with 70 percent in vitrified controls, and blastocyst formation rose to 59 and 56 percent from 40 percent.

At the 100 micromolar concentration, carnosine significantly reduced reactive oxygen species fluorescence and increased the number of NANOG-positive epiblast cells in the resulting embryos compared with conventional vitrification. JC-1 ratios were numerically higher with carnosine, which the authors describe as suggesting a potential improvement in mitochondrial membrane potential, although this measure did not reach statistical significance. Descriptive NADH and FAD autofluorescence imaging in one independent experiment showed higher signals with carnosine.

To explore the molecular basis of the effect, the researchers performed proteomic and transcriptomic analyses on the resulting two-cell embryos. Proteomics of late two-cell embryos identified carnosine-associated protein changes, including upregulation of the mRNA export scaffold protein Thoc2 and the actin-based motor Myo1c, along with downregulation of the stress chaperone Clusterin. Transcriptomics revealed 1,026 differentially expressed genes, enriched in functions related to transcriptional regulation, and changes in the cell fate determination-related gene Tfap2c were validated by RT-PCR.

The authors conclude that carnosine supplementation improved preimplantation development following mouse oocyte vitrification and was associated with reduced oxidative stress and increased epiblast cell numbers, with the mitochondrial observations and molecular profiling suggesting possible mechanisms. They note that these findings support further evaluation of carnosine as an additive for oocyte cryopreservation. As the work was conducted in mouse oocytes in a laboratory setting, and the molecular profiling was performed on early embryos, the results do not yet establish clinical benefits for human fertility treatment, and the article is an early-access version subject to further edits.

Subject of Research: Carnosine supplementation during vitrification of mouse oocytes and its effects on embryo development, oxidative stress and gene expression

Article Title: Carnosine enhances mouse oocyte vitrification outcomes with associated redox and transcriptional changes

Article References: Wang, X., Tang, J., Zhu, M., Yan, B., Hua, M., Shi, H., Wang, J., & Liu, M. (2026). Carnosine enhances mouse oocyte vitrification outcomes with associated redox and transcriptional changes. Journal of Ovarian Research. https://doi.org/10.1186/s13048-026-02320-6

Image Credits: AI Generated

DOI: 10.1186/s13048-026-02320-6

Keywords: carnosine, oocyte vitrification, fertility preservation, oxidative stress, mitochondria, blastocyst, preimplantation development, proteomics, transcriptomics, mouse oocytes, cryopreservation, enhances