Objective: To study the motility characteristics of epididymal spermatozoa after spermatogonial stem cell transplantation.
Design: Testicular cells from fertile donor mice were transplanted to the testis of genetically sterile recipient mice. Three to nine months later, the epididymal spermatozoa were isolated and used for a computer-assisted sperm motility analysis. Spermatozoa from fertile adult mice were used as control.
Setting: Murine transplantation model in an academic research environment.
Animal(s): Donors, 6-day-old male C57Bl x WBRej F1 mice; acceptors, 4- to 6-week-old W/W(v) mice of the same genetic background.
Intervention(s): Two to 10 microL from a 30-million/mL testicular cell suspension was injected through the efferent duct in the rete testis.
Main outcome measure(s): Vitality, concentration, motility, individual sperm movement, and hyperactivity of the spermatozoa.
Result(s): Vitality was comparable between the two groups; the concentration, motility, and hyperactivity of posttransplantation spermatozoa were significantly reduced. The movement pattern of the individual spermatozoon was normal at the time of isolation but decreased more rapidly during in vitro culture, compared with the case in controls. This difference already had reached a significant level 3 hours after culture, which is comparable with the duration of an IVF procedure.
Conclusion(s): The reduced fertilization rate after IVF can thus be explained by a lower number of motile spermatozoa and the faster decrease of the individual sperm movement parameters.