Correlation between female pronuclear/cytoplasmic ratio and number of chromosomes in mouse zygotic stage: implications for aneuploidy assessment in ART.

PURPOSE: The objective of this study was to investigate the correlation between the pronuclear/cytoplasmic (PN/C) ratio and the number of chromosomes in mouse zygotes to understand the implications of pronuclear size regulation in early embryonic development. METHODS: A combination of enucleation and aggregated chromosomes/chromatin (AC) transfer was utilized to create oocytes with varying numbers of chromosomes. Time-lapse imaging and immunofluorescence staining were employed to analyze pronuclear dynamics and chromosomal configurations. RESULTS: Higher chromosome numbers correspond to a larger PN/C ratio. Oocytes with a higher number of chromosomes exhibited larger pronuclei. CONCLUSION: The study underscores the complexity of pronuclear size regulation and its correlation with the number of chromosomes. The findings suggest potential applications in ART, where assessing the PN/C ratio could serve as a biomarker for zygote quality and aneuploidy.