Sperm functional changes and fertilization in vitro in co-culture with human skin fibroblasts

This study was undertaken to evaluate the effects of human skinfibroblast monolayers on human sperm function and fertilizationin vitro. Sperm function was evaluated using the hamster oocytepenetration assay (HOPA) and zona binding assay (ZBA) in mediumalone and in co-culture with human skin fibroblast monolayersand suspensions. The ZBA was also studied in fibroblast conditionedmedium and in bovine oviduct cell monolayers and suspensions.Fertilization was measured both in in-vitro fertilization (IVF)couples with a normal semen analysis (first study; randomized)and in IVF couples with subnormal semen analysis (second study;each patient served as its own control). The HOPA results werenot significantly different with or without fibroblasts. Inall co-culture situations and in conditioned medium the ZBAscored significantly lower than medium alone. No significantdifferences with respect to IVF were observed between the co-cultureand the control group in either study. The mean fertilizationrate per patient was 60% in the group with normal semen analysisand 25% in the group with abnormal semen analysis. From thisstudy we conclude that although co-culture with human skin fibroblastsand epithelial cells influences the results of some sperm functiontests, it does not influence fertilization in vitro.