A point of confusion for embryologists in the identification of viable spermatozoa by the eosin-nigrosin test / 대한생식의학회지

A viable spermatozoon is a prerequisite for fertilization in intracytoplasmic sperm injection (ICSI). Thus, it is crucial to select viable but immotile spermatozoa on the day of ICSI. We report conflicting results in the identification of viable but immotile spermatozoa between the eosin-nigrosin staining and the laser test, which resulted in confusion for embryologists during assisted reproductive technology (ART). Three patients’ semen samples that showed no motile spermatozoa are described in this report. To identify viable spermatozoa, we used both the eosin-nigrosin test and the laser test for each sample, and repeated the semen analysis twice in each patient. Viable but immotile spermatozoa selected by the laser test were used for ICSI. Viable spermatozoa were detected by both the eosin-nigrosin and laser tests in two patients (case 1, 95.00% vs. 24.21% and 92.68% vs. 22.22%; case 2, 41.18% vs. 23.48% and 39.81% vs. 22.52%), indicating consistent results between the two methods. In the third patient, the eosin-nigrosin test yielded viability rates of 20.75% and 19.14%, while the result of the laser test was 0%. Thus, testicular aspiration was performed to collect viable sperm from this patient. Normal fertilization was achieved after the injection of viable but immotile spermatozoa selected from these patients by the laser test, resulting in the birth of two healthy babies. Our study documents a case where the eosin-nigrosin test showed a limitation in identifying viable but immotile spermatozoa for ART, while the laser test may overcome this limitation. Larger samples may be required to corroborate the clinical value of the laser test.

Identification and selection of completely immotile but viable spermatozoa for assisted reproductive technology / 中华男科学杂志

Intracytoplasmic sperm injection (ICSI) remains the most effective method for severe male infertility patients to obtain their genetic offspring. A viable spermatozoon is the prerequisite for initiating fertilization in ICSI. Motility is the primary sign of sperm viability. However, how to select immotile but viable spermatozoa for ICSI on the day of ovum pick-up is critical for ICSI. This review focuses on the techniques for the identification and selection of immotile but viable spermatozoa for assisted reproductive technology.

A successful pregnancy using completely immotile but viable frozen-thawed spermatozoa selected by laser / 대한생식의학회지

The aim of this study was to report a successful pregnancy using completely immotile frozen-thawed spermatozoa selected by laser. A single laser shot was used to detect the presence of viable immotile spermatozoa in fresh and frozen-thawed testicular spermatozoa. The viability rate was 55.8% after the laser detection, and cryopreservation was carried out immediately. The thawing test was performed on the day of oocyte pick-up, and no motile sperm were observed after extending the culture for another 4 hours, while a survival rate of 39.8% was detected using the laser. In all, five mature oocytes were injected, resulting in four cases of normal fertilization (80%) on day 1. Further, two high-quality day 3 embryos were transferred, which resulted in a singleton pregnancy. Our study demonstrates that completely immotile spermatozoa are worth cryopreserving for further intracytoplasmic sperm injection, which provides a new insight into male fertility preservation in cases of completely immotile spermatozoa.