Leukocytospermia is associated with increased reactive oxygen species production by human spermatozoa

Objective: To investigate the role of increased seminal leukocytes in enhancing reactive oxygen species (ROS) production by human spermatozoa. Design: A prospective study. Setting: Male infertility clinic. Patient(s): Forty-eight infertile men. Intervention(s): Standard semen analysis. Assessment of sperm nuclear DNA damage by sperm chromatin structure assay. Incubation of spermatozoa from nonleukocytospermic samples with blood neutrophils. Main Outcome Measure(s): Spontaneous and phorbol 12-myristate 13-acetate (PMA)-induced ROS production in pure-sperm suspensions (after removal of leukocytes) as measured by a chemiluminescence assay. Result(s): Levels of spontaneous and PMA-induced ROS production in pure-sperm suspensions from the infertile men with a diagnosis of leukocytospermia (n = 16) were significantly higher compared with the case of infertile men without leukocytospermia (n = 32) and with the case of a control group of healthy volunteers (n = 13). A similar pattern of increased ROS was observed when spermatozoa were incubated with blood neutrophils. Leukocytospermia was associated with a significant decrease in sperm motility and increase in DNA damage. Conclusion(s): Increased seminal leukocytes may play a role in stimulating ROS production by human spermatozoa. Such stimulation may be mediated via direct cell-cell contact or by soluble products released by leukocytes. Poor sperm quality in leukocytospermic samples may be due to leukocyte-mediated oxidative stress.