ACTION OF PENTOXIFYLLINE DIRECTLY ON SEMEN

In the presence of pentoxifylline, spermatozoa can be induced to incre ase certain motion characteristics. This drug capability has been used to study the effect when applied directly on semen. An equal volume o f pentoxifylline was added to semen, which was then incubated for 1 h before processing. Sperm motion was assessed employing computer-assist ed semen analysis. The results showed that pentoxifylline increased cu rvilinear velocity, straight line velocity and lateral head displaceme nt, the latter effect being concentration-dependent over the entire ra nge of concentrations tested (r = 0.93, P < 0.0001). With a high conce ntration of pentoxifylline, spermatozoa exhibited characteristics cons istent with hyperactive-like motion. Semen characteristics showed mark ed interindividual variation, ranging from 0 to >40% response to 6 mM pentoxifylline challenge. Some 10% of patients showed little or no res ponse to pentoxifylline. The sum of the percentage changes in curvilin ear and straight line velocity, lateral head displacement and manual s perm count for each dose group was used to produce the stimulation ind ex, measuring the overall response of spermatozoa to the drug. This st imulation index showed that the most effective concentration was 6 mM pentoxifylline, considerably higher than the 3.6 mM pentoxifylline use d commonly for separated spermatozoa.