FORMATION OF REACTIVE OXYGEN SPECIES BY SPERMATOZOA FROM ASTHENOSPERMIC PATIENTS - RESPONSE TO TREATMENT WITH PENTOXIFYLLINE

Purpose: We determined the incidence of reactive oxygen species format ion by spermatozoa from asthenospermic patients, and the relationship between reactive oxygen species formation and sperm motion parameters. We also assessed the efficacy of in vitro and in vivo pentoxifylline treatment of asthenospermic patients whose spermatozoa generated high reactive oxygen species levels. Materials and Methods: Reactive oxygen species formation by spermatozoa from asthenospermic patients and fer tile volunteers was measured by chemoluminescence. Reactive oxygen spe cies formation by the sperm preparations was investigated without stim ulation (steady state), or after stimulation with N-formyl-methionyl-l eucyl-phenylalanine (f-MLP) or phorbol-12-myristate-13-acetate. Sperma tozoa from 15 asthenospermic patients whose spermatozoa produced high levels of reactive oxygen species at steady state were treated in vitr o with pentoxifylline to determine its effect on reactive oxygen speci es generation and sperm motion parameters. These same 15 patients and 18 with asthenospermia whose spermatozoa did not produce reactive oxyg en species at steady state were treated with pentoxifylline at 2 diffe rent dosages (300 and 1,200 mg. daily) to determine its effect on reac tive oxygen species generation, sperm motion parameters and sperm fert ilizing ability in vivo. Results: When reactive oxygen species formati on was detected in the steady state that was not stimulated by f-MLP, the source of reactive oxygen species could be attributed to the sperm atozoa themselves. Spermatozoa from 15 of 71 asthenospermic patients g enerated reactive oxygen species at steady state. Pentoxifylline decre ased reactive oxygen species generation by spermatozoa in these patien ts, and preserved the decrease of curvilinear velocity and beat cross frequency for 6 hours in vitro. For these patients orally administered pentoxifylline failed to decrease reactive oxygen species generation by spermatozoa, and had no effect on sperm motility, sperm motion para meters and sperm fertilizing ability at low dosage (300 mg. daily). Ho wever, it increased motility and beat cross frequency at high dosage ( 1,200 mg, daily) but it had no effect on sperm fertilizing ability. Co nclusions: Stimulation of sperm preparations with f-MLP can identify t he source of reactive oxygen species generated at steady state. Among asthenospermic patients there were some whose spermatozoa produced det ectable steady state levels of reactive oxygen species. In this group pentoxifylline appeared to be effective for decreasing reactive oxygen species formation and preserving sperm motion parameters in vitro. Or ally administered pentoxifylline had no effect at low dosage but it in creased sperm motility and some sperm motion parameters without alteri ng sperm fertilizing ability at high dosage.