[Screening of High-quality Spermatozoa Using Transwell Membrane Pores and Assessment of Their Performance]

The feasibility of using Transwell, based on the molecular sieve effect of its membrane pores, to select high-quality human sperm was explored.

A total of 162 fresh semen samples were collected from the Department of Andrology at the First Affiliated Hospital of Guangzhou University of Chinese Medicine between November 2023 and May 2024. Differences in sperm selection using 5 μm and 8 μm pore Transwell filters were analyzed, and microscopic structural differences were observed by transmission electron microscopy (TEM). Changes in semen parameters after 30, 60, and 80 minutes of Transwell sperm selection were compared. Differences in semen parameters after optimization of sperm of varying qualities by Transwell, density gradient centrifugation (DGC), and swim-up (SU) methods were also compared. In this study, the percentage of progressive motility (PR) of sperm was set as the primary outcome measure, while sperm motility, normal sperm morphology rate (NSMR), DNA fragmentation index (DFI), sperm concentration, and recovery rate were set as secondary outcome measures.

When the aperture is 5 μm and the preferred time is 60 minutes, the Transwell method yields better results for sperm selection. In the normal semen group, compared with the DGC method, the median percentage of PR in sperm after Transwell selection increased from 77.50% to 92.05% (P < 0.05), the median NSMR increased from 9.00% to 13.25% (P < 0.01), and the median DFI decreased from 2.16% to 0.25% (P < 0.01). Compared with the SU method, the median sperm concentration after Transwell selection increased from 4.70 × 10⁶ mL^－1 to 14.15 × 10⁶ mL^－1 (P < 0.01), the median DFI decreased from 0.47% to 0.25% (P < 0.01), and the median recovery rate increased from 2.50% to 6.48% (P < 0.01). but there were no statistically significant differences in sperm motility, PR percentage, or NSMR. In the abnormal semen group, compared with the DGC method, the median PR percentage of sperm after Transwell selection increased from 37.20% to 88.75% (P < 0.01), the median sperm motility increased from 53.00% to 95.00%, and the median DFI decreased from 12.49% to 0.92% (P < 0.01). Compared with the SU method, the median PR percentage of sperm after Transwell selection increased from 86.30% to 88.75% (P < 0.05), and the median DFI decreased from 1.63% to 0.92% (P < 0.05).

The Transwell preferred method demonstrates excellent performance in obtaining sufficient sperm with high viability, good morphology, and good DNA integrity. This makes it a promising, simple, and practical method for selecting high-quality sperm in assisted reproductive technologies.