Sperm-damaging effects of electric current: possible role of free radicals.

The generation of reactive oxygen species (ROS) and sperm damage was evaluated in (a) samples obtained during electroejaculation (EE) of men with spinal cord injury and (b) in electrolyzed HAM's F-10 medium subjected to electric current in vitro. Chemiluminescence data showed a significant increase in ROS in the ejaculates (6 x 10(7) photons/ml) collected immediately after EE and in the electrolyzed medium (3 to 7 x 10(6) photons/ml) when compared to the control (4 to 7 x 10(4) photons/ml). Incubation of normal human sperm with the electrolyzed medium resulted in a significant threefold decrease in percent motility and a twofold decrease in percent viability. Sperm subjected to direct electric stimulation in vitro exhibited a significant twofold decrease in percent motility and percent viability. Superoxide dismutase (SOD) activity decreased significantly in sperm subjected to direct electric current in comparison to the control or the sample incubated with electrolyzed medium. These studies indicate that in vitro and in vivo electrical stimulation generate reactive oxygen species and affect SOD activity, which in part are responsible for decreased sperm motion and viability.