Effect of lysoplatelet-activating factor on human sperm fertilizing ability

OBJECTIVE: To evaluate the penetration rates in the hamster zona-free oocyte sperm penetration assay (SPA) after exposure of spermatozoa to lysoplatelet-activating factor (LPAF) and lysophosphatidyl choline (LPC). DESIGN: Washed human spermatozoa were exposed to 100 microM of LPAF or LPC, followed by the assessment of their fertilizing ability using the SPA. The percentage of penetration, the sperm binding in the SPA, the percentage of motile spermatozoa, and the acrosome reaction rates were quantified. SETTING: Private research and university laboratories. PATIENTS, PARTICIPANTS: Fresh and frozen semen samples from fertile donors with proven fertility were used as well as fresh semen from infertile patients attending a fertility clinic. All the infertile patients had abnormal semen analysis. INTERVENTIONS: Human spermatozoa were incubated for 90 minutes in the presence or absence of LPAF or LPC at 100 microM with 0.3% albumin in Ham's F-10 (GIBCO, Dorval, Quebec, Canada), and their fertilizing ability was evaluated using the SPA. The effect of these lysophospholipids on the percentage of acrosome reaction was evaluated with a fluorescent microscopy technique. RESULTS: The penetration rates of the SPA in male factor increased significantly from 3% +/- 6% with controls to 19% +/- 9% and 34% +/- 22% after incubation with LPC and LPAF, respectively. Sperm-oocyte binding was not significantly increased in this group. Sperm penetration assay penetration rates were also increased in fertile cryopreserved spermatozoa with LPC and LPAF. In this group, the acrosome reaction was significantly increased from 2% +/- 1% in controls to 10% +/- 6% and 8% +/- 3% after incubation with LPC and LPAF, respectively. CONCLUSION: Lysoplatelet-activating factor and LPC independently increased the penetration rate of spermatozoa and the percentage of acrosome reaction. Lysophosphatidylcholine and LPAF may be beneficial in the treatment of spermatozoa with male factor infertility and may increase fertilization rates in IVF.