A METHOD OF SHORT-TERM CRYOSTORAGE AND SELECTION OF VIABLE SPERM FOR USE IN THE VARIOUS ASSISTED REPRODUCTIVE TECHNIQUES

The objective of this study was to determine if spermatozoa, following short-term cryostorage at 5 degrees C in Test-Polk buffer (TYB; ZBL, Inc., Lexington, KY, USA), could be recovered and improved via the Spe rmPrep(TM) filtration method and to assess the possibly enhanced ferti lizing capacity of the selected spermatozoa. Semen specimens from 20 m en mere collected, evaluated, diluted 1:1 (v/v) with TYB, divided into aliquots and cooled to 5 degrees C for 24 and 48 hr. Semen samples we re assessed for volume, sperm count, percentage and grade of motility, percentage of morphologically normal spermatozoa and outcome of the s perm penetration assay (SPA). After storage, aliquots were rewarmed at 37 degrees C, centrifuged, and the pellet was resuspended in 1.0 ml o f SpermPrep(TM) media (ZBL, Inc.). Following 15 min of incubation, the rewarmed spermatozoa, were filtered via the SpermPrep(TM) I filtratio n column (ZBL, Inc.) and assessed accordingly. The results obtained in this study indicate that the short-term cryostorage procedure yielded spermatozoa of adequate qualitative characteristics when compared to the fresh spermatozoa. Furthermore, filtration of rewarmed specimens y ielded spermatozoa of significantly higher qualitative characteristics and superior fertilizing capacity following a short-term cryostorage period in TYB when compared to fresh and rewarmed spermatozoa (p < 0.0 5). This method of short-term cryostorage in TYB and selection of supe rior spermatozoa via the SpermPrep(TM) filtration method could further enhance the fertilizing ability of patients who produce spermatozoa c haracterized by deficient capacitation acrosome reaction and subsequen t fertilization.