Related Experiment Video
Updated: Sep 23, 2025
Author Spotlight: Elucidating the Dynamics of Mechano-Transduction and Nuclear Agitation in Mouse Oocytes
Published on: January 12, 2024
Quantitative evaluation of intercellular local deformation of human oocytes during Piezo-assisted intracytoplasmic
Hiroshi Iwayama1, Masanori Yamashita1
1Yamashita Ladies' Clinic, Kobe, Hyogo, Japan.
Objective:
To evaluate the relationship between the quantitative properties of local deformation of the ooplasm during Piezo-assisted intracytoplasmic sperm injection (Piezo-ICSI) and oocyte developmental fate after Piezo-ICSI.
Design:
Video-based motion analysis and case-control study.
Setting:
Private fertility center.
Patient(S):
A total of 99 couples assigned to the standard Piezo-ICSI program.
Intervention(S):
Video recordings of the sperm injection process during Piezo-ICSI.
Main Outcome Measure(S):
Quantitative deformation properties consisting of the orientation of deformation perpendicular (Perp) or parallel (Para) to the oolemma and the mechanical response of the ooplasm (elongation, contraction, and total): Perp-elongation, Perp-contraction, Perp-total, Para-elongation, Perp-contraction, and Para-total.
Result(S):
The deformation parameters were compared among different angular ranges of 30°-60°, 60°-90°, 90°-120°, and 120°-150° (defined as 0° at the 3 o'clock puncture site). The Perp-total value at 30°-60° was significantly greater than that at the other angles (130.2 vs. 57.7-85.5, respectively) primarily due to substantially greater Perp-elongation values. The Para-total value at 30°-60° was significantly greater than that at the other angles (20.1 vs. 6.7-10.3, respectively) primarily due to substantially smaller Para-contraction values. The deformation parameters of the ooplasm adjacent to the first polar body were also compared among different developmental fates (fertilization failure, cleavage arrest, and blastocyst development). The Perp-total value of oocytes derived from blastocyst formation was significantly smaller than those derived from other developmental fates (58.1 vs. 70.0-87.3, respectively).
Conclusion(S):
The Piezo-ICSI process induced deformation with various mechanical behaviors in different regions within a single oocyte. Furthermore, the exposure of the ooplasm adjacent to the first polar body to excessive deformation was found to be a possible trigger for adverse fertilization and embryo development after Piezo-ICSI.
