Variability of the response to pentoxifylline in vitro in infertile normozoospermic and asthenozoospermic patients.

The in vitro effect on the motility of spermatozoa of the methylxanthine pentoxifylline was studied in 30 patients consulting for infertility (13 normozoospermic and 17 asthenozoospermic). After separation by centrifugation on Percoll gradient, the spermatozoa were incubated for 30 min in pentoxifylline (3.6 mM), then the pentoxifylline was removed by washing and centrifugation. The residual effect of pentoxifylline was studied by computer-assisted videomicrographic analysis of the sperm motion parameters. In both groups of patients a decrease in the percentage of motile spermatozoa after exposure to pentoxifylline was observed, as compared with a control group. The effect on the motion parameters varied according to the time of observation (30, 120, 240 min). In the asthenozoospermic patients, the curvilinear velocity (VCL) was not modified in a statistically significant manner. In the normozoospermics, the VCL was increased after exposure to pentoxifylline at 120 min (p = .03) and 240 min (p = 10(-5)); similarly, the amplitude of the lateral head displacement (ALH) was greater in this group at 120 and 240 min (p = .01 for maximum ALH). However, a heterogeneity was noted in the response between individuals, which required that the statistical analyses take into account these differences.