Relative contribution of leukocytes and of spermatozoa to reactive oxygen species production in human sperm suspensions

The contribution of leukocytes and of spermatozoa to reactive oxygen specie s (ROS) production in prepared sperm suspensions from donors and subfertili ty patients was compared. In both groups, more leukocytes/10(6) spermatozoa were counted in samples which produced detectable ROS than in those that d id not: Donors - 645 vs. 170 (medians, n = 7; p < 0.01, Kruskal-Wallis), Su bfertile group - 1785 (n = 18) vs. 11 (n = 8) (p < 0.005, Kruskal-Wallis), respectively. Leukocyte concentrations were correlated with basal (r = 0.82 6, p < 0.001) and with ROS production stimulated with 50 mu mol N-formyl, m et, leu, phe l(-1) (N-FMLP) (r = 0.835, d < 0.001) and 100 nmol phorbol 12- myristate 13-acetate l(-1) (PMA) (r = 0.835, p < 0.001) measured using a ch emiluminescence assay. Leukocytes were removed from the sperum suspensions of 6 donors and from 96 ejaculates from 21 subfertility patients and ROS pr oduction was determined. Subsequently, in all 6 donors, N-FMLP did not stim ulate ROS production indicating that leukocyte removal was complete, though in one case PMA stimulated low levels of ROS production. In 65 ejaculates from subfertile men the N-FMLP response was completely eliminated but in 7 of these samples PMA continued to stimulate ROS production. We conclude tha t infiltrating leukocytes are the predominant source of ROS production in u npurified sperm preparations. Some purified sperm suspensions could be stim ulated to produce ROS by the addition of PMA indicating that spermatozoa th emselves may produce ROS, albeit in much smaller amounts.