The effect of sildenafil on human sperm motion and function from normal and infertile men

The aim of this report was to study the effect of sildenafil, a specific ty pe-5 phosphodiesterase inhibitor, on human sperm motility, viability, membr ane integrity and sperm penetration assay. Spermatozoa were obtained from normal donors (n = 6) and infertile men (n = 6) were washed using a single Percoll (80%) gradient, suspended in Ham's F -10 medium, and incubated with various doses of sildenafil (125, 250 and 75 0 ng/ml); pentoxifylline (3 mM) was used as a positive control, and Ham's F -10 was used as a reagent control. Sperm motility, grade, viability, membra ne integrity (by hypo-osmotic swelling test), and motion evaluation were ca rried out at various time intervals. Hamster ova sperm penetration assay (S PA) was used to evaluate overall sperm function. Sildenafil did not affect sperm motility, viability or membrane integrity u nder these conditions as compared to our Ham's control (P > 0.05). Incubati on with pentoxifylline significantly enhanced sperm motility (P < 0.05) and viability without affecting membrane integrity (P < 0.05). Sperm incubated with sildenafil and pentoxifylline from both normal donors and infertile p atients demonstrated no significant change in sperm penetration assay from respective controls. In conclusion, sildenafil, at the doses evaluated, did not significantly al ter the motility, viability, membrane integrity or sperm penetration charac teristics of human spermatozoa from normal donors and infertile patients.