Value of Meiotic Spindle Imaging on Fertilization and Embryo Development Following Human Oocyte Piezo-ICSI

Abstract

Background: The objective of this study was to investigate accurately the effect of the meiotic spindle imaging of human oocytes on their fertilization and embryo development by using the Piezo-ICSI. Methods: We retrospectively assessed 529 oocytes with the first polar body retrieved from 124 infertile couples (147 cycles) who attended our clinic between May 2016 and December 2018. Of these, 489 oocytes (92.4%) with visible meiotic spindle comprised the Spindle (+) group and 40 oocytes (7.6%) not observed meiotic spindle comprised the Spindle (−) group. The meiotic spindle was imaged using polarized light microscopy. The rates of fertilization, high-quality day-3 embryo, day-5 blastocyst, and high-quality day-5 blastocyst were evaluated in both groups. Results: The fertilization rates of Spindle (+) and Spindle (−) were 92.0% (450/489) and 70.0% (28/40), respectively; high-quality day-3 embryo rates were 62.9% (283/450) and 35.7% (10/28); day-5 blastocyst rates were 53.7% (205/382) and 32.1% (9/28); high-quality day-5 blastocyst rates were 29.8% (114/382) and 3.6% (1/28). Fertilization, high-quality day-3 embryo, day-5 blastocyst, and high-quality day-5 blastocyst rates were significantly higher in the Spindle (+) group than in the Spindle (−) group. Conclusion: Spindle imaging (i.e., oocytes with a visible meiotic spindle or with not observed meiotic spindle) influences the outcome of Piezo-ICSI in human oocytes, including fertilization and embryo development. To our knowledge, this study is the first to evaluate the effect of meiotic spindle imaging on fertilization or embryo development among oocytes after Piezo-ICSI. The meiotic spindle imaging could be the indicator for the quality management of medical doctors and embryologists.