The sequential effects of human cervical mucus, oviductal fluid, and follicular fluid on sperm function

Objective: To compare the sequential effects of human cervical mucus (CM), oviductal fluid, and follicular fluid (FF) on sperm motility, hyperactivation, and the acrosome reaction during 9 hours of incubation in vitro.

Design: Spermatozoa from a fertile donor were allowed to penetrate human CM in vitro and then were recovered and incubated in either 30% human oviductal fluid or a simple salt solution for 3 hours before challenge with 20% FF. Thus, the sequential effects of the fluids collected from the female reproductive tract on sperm hyperactivation and acrosome reaction were examined.

Setting: The donor insemination program at the University Clinic within the Jessop Hospital for Women, Sheffield, United Kingdom.

Patients: All donors used in this study were involved in the donor insemination program.

Main outcome measures: Sperm motility, hyperactivation, and percentage of acrosome-reacted spermatozoa were measured.

Results: This study used an in vitro technique to mimic sperm transport in vivo. Spermatozoa sequentially incubated with female reproductive tract secretions in vitro showed a maintenance in the level of FF-induced hyperactivated motility and a decreased response to the FF-induced acrosome reaction when compared with sperm challenged with FF in the absence of prior incubation with human oviductal fluid.

Conclusion: It is suggested that human oviductal fluid may serve to delay the FF-induced acrosome reaction.