Related Experiment Videos
Improvement of post-thaw sperm motility in poor quality human semen
C Sawetawan1, E S Bruns, G S Prins
1Department of Obstetrics and Gynecology, University of Illinois College of Medicine, Chicago.
Objective:
To find alternative cryopreservation methods to improve the post-thaw fertilizing capacity of poor quality human sperm.
Design:
Controlled clinical study.
Setting:
Fertility clinic of a teaching hospital.
Patients:
Men with poor quality semen samples, i.e., asthenozoospermia (< 40% motile sperm) and/or oligozoospermia (< 20 x 10(6) sperm/mL). Fertile sperm donors were used for comparison.
Interventions:
Semen samples were divided into four aliquots and slowly diluted 1:1 with: [1] n-tris (hydroxymethyl) methyl-2-amino ethane sulfonic acid (TES) and tris (hydroxymethyl) aminomethane (Tris)-citric acid-egg yolk buffer with 12% glycerol (TEST), [2] TEST+CryoSeeds (Cell Systems, Ltd., Cambridge, UK), [3] TEST + 10 mM dithiothreitol (DTT), or [4] TEST+CryoSeeds + 10 mM DTT. Cryovials were frozen using slow staged cooling and static vapor freeze and stored at -196 degrees C.
Main Outcome Measure:
The frozen aliquots were randomly thawed and, after 15 minutes at 37 degrees C, motion analysis was performed.
Results:
The percent motility after freeze-thaw in TEST was significantly decreased to 42 +/- 5% of prefreeze motility (P < 0.001). Addition of CryoSeeds with holding at -5 degrees C for 10 minutes resulted in 47 +/- 6% of prefreeze motility, which was not different than TEST alone. Addition of DTT to TEST significantly improved post-thaw motility over TEST alone to 71 +/- 7% of initial motility (P < 0.01). The combination of CryoSeeds and DTT further improved post-thaw motility to 80 +/- 10% of initial motility, which was not different than the neat semen.
Conclusion:
The present results suggest that DTT, a reducing agent that prevents oxidation of sulfhydryl groups, protects poor quality spermatozoa from excessive cryodamage. Thus, DTT along with seeding may be a useful addition when long-term storage of poor quality semen is crucial for maintaining reproductive potential.