Generation of reactive oxygen species in subgroups of infertile men

The capacity to generate reactive oxygen species (ROS), both basally and after stimulation with the calcium ionophore A23187, was examined in the motile fraction of sperm isolated after swim-up from the semen of 10 naturally fertile men and three groups of infertile patients. The latter included: (1) men with a non-bacterial inflammation of the genital tract (n = 10); (2) men unable to impregnate their partners during an intra-uterine insemination programme (IUI) (n = 8) and their matched controls (n = 6); and (3) men with hypogonadotrophic hypogonadism (HH) who remained infertile after induction of spermatogenesis with gonadotrophin or gonadotrophin-releasing hormone therapy (n = 3) and their matched controls (n = 3). The levels of ROS production were elevated in the sperm of some infertile men with inflammation of the genital tract compared to those found in 10 naturally fertile men. In addition, sperm from those patients who remained infertile after an IUI programme produced higher amounts of ROS compared to their control group who became fertile. Similarly, the production of ROS by sperm from three patients with HH who remained infertile was significantly higher than those of the three men who became fertile. These data suggest that an excessive production of ROS by sperm may explain some cases of idiopathic male infertility.