The split ejaculate: assessment of fertility potential using two in vitro test systems

Summary: Semen samples (split & whole ejaculates) were obtained from 12 normal men (group A) and 8 oligospermic infertile men with sperm concentrations of less than 20 times 106 sperm/ml (group B). All samples were evaluated by standard semen analysis, bovine cervical mucus penetration assay (CMPT), and, in all cases with sufficient sperm, in the human spermatozoa zona-free hamster in vitro penetration assay (SPA). In group A the motile sperm concentration was significantly higher in the ejaculated material of the first two contractions (fraction I or FI) than in the remainder of the ejaculate (fraction II or FII) (p < 0.02). No significant differences were observed in sperm penetration into zona-free hamster ova or bovine cervical mucus by sperm from FI, FII or the whole ejaculate. Motile sperm concentration was significantly correlated with sperm penetration into bovine cervical mucus (r = 0.65, p < 0.01), but not into zona-free hamster ova (r = 0.01 NS). In the samples collected by group B, the mean sperm concentration and motile sperm concentration were higher in the first (FI) than in the second (FII) fractions of the split ejaculate or the whole ejaculate (p < 0.05). No significant differences were found among the FI, FII and the whole ejaculate semen samples for penetration of sperm into bovine cervical mucus. Sperm concentration and motile sperm concentration were significantly correlated with sperm penetration into bovine cervical mucus (r = 0.58, p < 0.01 and r = 0.57, p < 0.01, respectively). Our results suggest that the lack of efficacy of the technique of split ejaculate for AIH may be due to lack of effective enrichment of the first fraction with functionally enhanced sperm. If the split ejaculate technique is attempted, we recommend that the fraction with the highest motile sperm concentration be used. Zusammenfassung: Von 12 normalen Mannern (Gruppe A) und 8 infertilen Mannern mit Oligozoospermie bei Spermatozoenkonzentrationen von weniger als 20 times 106/ml (Gruppe B) wurden Samenproben (Split- und vollstandige Ejakulate) untersucht. Alle Sa-menproben wurden untersucht mit Standard-Samen Analyse, Rinderzervikalschleim-Pene-trationsassay (CMPT) und in alien Fallen mit hinreichendem Samen im Humanspermato-zoen-zonafreies-Hamsterei-Penetrationsassay (SPA). In Gruppe A war die Konzentration motiler Spermatozoen signifikant hoher in dem ejakulierten Material der ersten zwei Kontraktionen (Fraktionen I oder FI) als im Rest des Ejakulates (Fraktion II oder FII) (p