EFFECT OF PLATELET-ACTIVATING-FACTOR, LYSO-PLATELET-ACTIVATING-FACTOR, AND LYSOPHOSPHATIDYLCHOLINE ON SPERM MOTION - IMPORTANCE OF ALBUMIN FOR MOTILITY STIMULATION

Objectives: To determine the effect of platelet-activating factor (PAF ), the PAF derivative lyso-PAF, and lysophosphatidylcholine on in vitr o sperm motility and to determine the role of albumin in this interact ion. Design: Washed human spermatozoa were exposed to a range of PAF, lyso-PAF, or lysophosphatidylcholine concentrations, supplemented with different albumin concentrations, and the effect on sperm motion was quantified with a computer-assisted motion analysis. The metabolism of these compounds by spermatozoa was also assessed. Setting: University research laboratory. Patients, Participants: Semen samples were obtai ned from donors and patients attending an infertility clinic. Interven tions: Human spermatozoa were incubated with PAF, lyso-PAF, or lysopho sphatidylcholine at 10(-11) to 6 X 10(-4) M, with 0% to 1.2% albumin, and motility was evaluated at different time periods from 5 to 240 min utes. Tritiated PAF, lyso-PAF, or lysophosphatidylcholine was incubate d with spermatozoa, and the metabolites were separated and quantified by thin-layer chromatography (TLC). Main Outcome Measures: Sperm motio n characteristics, including the percentage of motile spermatozoa, vel ocity, and linearity, and sperm viability were determined. The metabol ism of PAF, lyso-PAF, and lysophosphatidylcholine by spermatozoa was a lso studied. Results: Fifty micromolar of PAF and 100 muM lyso-PAF, su pplemented with 0.3% albumin, increased sperm linear velocity by 41% /- 5% (+/- SEM) and 44% +/- 5% and curvilinear velocity by 17% +/- 3% and 21 +/- 3%, respectively. Lysophosphatidylcholine had a similar eff ect but only at 22-degrees-C and not 37-degrees-C. In the absence of a lbumin, neither PAF, lyso-PAF, or lysophosphatidylcholine induced incr eases in sperm motion. Lysophosphatidylcholine and lyso-PAF are not de tectably metabolized by spermatozoa, whereas 12.5% +/- 1.2% of PAF is hydrolyzed to lyso-PAF in 1 hour. Conclusion: Platelet-activating fact or, lyso-PAF, and lysophosphatidylcholine independently stimulate sper m linear and curvilinear velocity. This action requires albumin. These compounds may be of use in the treatment of asthenozoospermic males.