Improvement of post-thaw sperm motility in poor quality human semen.
OBJECTIVE
To find alternative cryopreservation methods to improve the post-thaw fertilizing capacity of poor quality human sperm.


METHODS
Controlled clinical study.


METHODS
Fertility clinic of a teaching hospital.


METHODS
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.


METHODS
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.


METHODS
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.


CONCLUSIONS
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.
Sawetawan
C
C
Department of Obstetrics and Gynecology, University of Illinois College of Medicine, Chicago.
Bruns
E S
ES
Prins
G S
GS
D015925:Cryopreservation / Q000379:methods*; D004229:Dithiothreitol / Q000494:pharmacology; D004338:Drug Combinations; D005615:Freezing; D006801:Humans; D008297:Male; D009845:Oligospermia / Q000503:physiopathology; D012016:Reference Values; D013076:Sperm Count / Q000187:drug effects; D013081:Sperm Motility / Q000187:drug effects; D014325:Tromethamine / Q000031:analogs & derivatives / Q000494:pharmacology
D004338:Drug Combinations; D014325:Tromethamine; C004551:TES; C027806:TEST mixture; D004229:Dithiothreitol