Utilisation of Oocyte Diameter as a Non-invasive Indicator of Oocyte and Embryo Quality: Investigating Protein Kinase B Protein Expression in Cumulus-Granulosa Cells and Embryo Morphokinetics.

Background: Oocyte diameter is crucial for initiating meiosis and supporting the maturation capability, a prerequisite for successful fertilisation and high-quality embryo development. While numerous studies have explored the correlation between oocyte diameter and embryo development capacity in animal models, limited research appears concerning human oocytes.

Aim: This study aims to ascertain whether oocyte diameter can serve as a reliable predictor of oocyte and embryo quality, achieved through its correlation with protein kinase B (Akt) protein levels on cumulus-granulosa cells and blastocyst morphokinetics.

Setting and design: Prospective cohort study included cumulus-granulosa cells collected from 228 mature oocytes of 32 infertile women undergoing in vitro fertilisation treatment. The diameter of the oocytes was measured using the Image J software, and the samples were categorised into three groups based on their diameter: <105.95 µm, 105.96-118.96 µm and >118.97 µm. Quantification of pAkt and Akt protein total of cumulus-granulosa cells exploited the ELISA method. Embryo morphokinetics and anomaly development events were observed at the blastocyst stage to evaluate embryo quality relative to oocyte diameter.

Statistical analysis used: The Kruskal-Wallis test and Chi-square test were used. P <0.05 was considered statistically significant.

Results: The study revealed no notable difference in pAkt and Akt protein total in cumulus-granulosa cells among the three groups (P > 0.05). Likewise, there were no significant differences in morphokinetics and anomaly development except for the S2 parameter and reverse cleavage.

Conclusion: Reflecting on the molecular profile including pAkt, total Akt protein, morphokinetics and anomaly development, it was observed that oocyte diameter does not correlate with its competency and the quality of the resulting embryo. In addition, oocytes with a diameter below 105.95 µm may have an equal potential to develop into top-quality embryos.