Dysmorphic patterns are associated with cytoskeletal alterations in human oocytes

Area of Science:

• Reproductive biology
• Cell biology
• Embryology

Background:

• Oocyte morphology is used for selection in IVF treatments, but its link to intrinsic cellular characteristics is poorly understood.
• Assessing oocyte quality relies on morphological criteria, yet the implications for cytoskeleton integrity are controversial.

Purpose of the Study:

• To investigate the association between specific morphological anomalies in human oocytes and damage to the meiotic spindle and actin cytoskeleton.
• To determine if oocyte morphology reflects underlying cytoskeletal and chromosomal organization issues.

Main Methods:

• 170 human metaphase II oocytes were analyzed: 62 normal, 54 with SER clusters, and 54 with GC.
• Oocytes were stained for tubulin, chromatin, and actin; spindle dimensions, chromosome alignment, and cortical actin integrity were evaluated using confocal microscopy.

Main Results:

• Oocytes with SER and GC anomalies exhibited significantly altered spindle dimensions (length, width, area) compared to normal oocytes.
• GC oocytes showed higher rates of chromosome misalignment and disorganization.
• Cortical actin integrity was compromised in SER (66.7%) and GC (42.9%) oocytes compared to controls (100%).

Conclusions:

• Morphological anomalies, specifically SER aggregates and GC, are indicative of intrinsic damage to the oocyte's cytoskeleton, affecting spindle and actin organization.
• These findings suggest that cytoskeleton and chromosome organization parameters can serve as objective biomarkers for oocyte quality assessment in IVF.