Vitality of oligozoospermic semen samples is improved by both swim-up and density gradient centrifugation before cryopreservation.
OBJECTIVE
To ascertain whether washing sperm from oligozoospermic and normozoospermic samples before cryopreservation improves post-thaw vitality.


METHODS
Normozoospermic (n = 18) and oligozoospermic (n = 16) samples were divided into three aliquots. The first aliquot remained untreated and the second and third aliquots were subjected to the swim-up and discontinuous density gradient sperm washing techniques respectively. Vitality staining was performed, samples mixed with cryopreservation media and frozen. Spermatozoa were thawed, stained, and vitality quantified and expressed as the percentage of live spermatozoa present.


RESULTS
Post-thaw vitality in untreated aliquots from normozoospermic samples (24.9% +/- 2.3; mean +/- SEM) was significantly higher (unpaired t-tests; P < 0.01) than untreated oligozoospermic samples (11.9% +/- 2.3). Post-thaw vitality was significantly higher after swim-up in normozoospermic samples (35.6% +/- 2.1; P < 0.001; one-way ANOVA) and oligozoospermic samples (27.7% +/- 1.7; P < 0.01). Density gradient centrifugation significantly improved post-thaw vitality in oligozoospermic (22.4% +/- 1.0; P < 0.01) but not normozoospermic (30.8% +/- 1.8) samples.


CONCLUSIONS
Sperm vitality in cryopreserved oligozoospermic samples was improved by both the swim-up and density gradient centrifugation washing techniques prior to freezing.
Counsel
Madeleine
M
Concept Fertility Centre, King Edward Memorial Hospital, Subiaco, Western Australia, Australia.
Bellinge
Rhys
R
Burton
Peter
P
D002469:Cell Separation / Q000379:methods*; D002470:Cell Survival; D002499:Centrifugation, Density Gradient / Q000379:methods*; D015925:Cryopreservation / Q000379:methods*; D006801:Humans; D008297:Male; D009845:Oligospermia / Q000473:pathology*; D012661:Semen; D013094:Spermatozoa / Q000473:pathology*; D013696:Temperature; D013997:Time Factors