Sperm Selection Using Micro Swim-Up: Improvement of Chromatin Integrity Compared to Density Gradient Centrifugation

Area of Science:

• Reproductive Biology
• Spermatozoa Analysis
• Assisted Reproductive Technologies

Background:

• Sperm selection is critical for assisted reproductive technologies (ART).
• Conventional density gradient centrifugation (DGC) may induce sperm DNA damage due to centrifugation stress.
• Micro swim-up (MSU) is a centrifugation-free sperm selection method.

Purpose of the Study:

• To compare the efficacy of micro swim-up (MSU) and density gradient centrifugation (DGC) in selecting spermatozoa with optimal nuclear integrity.
• To evaluate sperm DNA fragmentation, nuclear immaturity, and chromatin decondensation after selection using MSU versus DGC.

Main Methods:

• Semen samples (n=90) were analyzed before and after sperm selection.
• Evaluated parameters included rapid progressive motility, sperm DNA fragmentation (SCD test), nuclear immaturity (aniline blue staining), and chromatin decondensation (chromomycin A3 staining).
• Compared outcomes between MSU and DGC sperm selection techniques.

Main Results:

• Both MSU and DGC improved sperm motility and nuclear parameters compared to unselected samples.
• MSU demonstrated significantly better results than DGC across all nuclear integrity markers.
• MSU markedly reduced sperm DNA fragmentation (1% vs 9.25%), nuclear immaturity (5% vs 15%), and chromatin decondensation (5.5% vs 13.5%) compared to DGC.

Conclusions:

• Micro swim-up (MSU) selects spermatozoa with superior nuclear integrity compared to density gradient centrifugation (DGC).
• MSU significantly reduces sperm DNA fragmentation and improves chromatin maturation.
• MSU presents a promising alternative to centrifugation-based methods for clinical ART applications.