Seminal plasma superoxide dismutase activity following radiotherapy: Protection by the exogenous enzyme and effects of intracellular inhibition.
For referred subfertile, radiation-exposed and known fertile males seminal plasma superoxide dismutase activity did not correlate with sperm density, % sperm motility, sperm velocity or penetration in the sperm penetration assay (SPA), but was found to correlate positively with seminal plasma zinc. A study of seminal plasma superoxide dismutase in relation to post-irradiation clinical treatment time provided tentative evidence that following a radiation challenge, superoxide dismutase might be subject to induction. When sperm intracellular superoxide dismutase was inhibited by incubation with diethyldithiocarbamate (DDC) in defined culture medium, motility ceased within 30 min but there was no associated rise in lipid peroxidation. Sperm pretreatment with DDC at concentrations as low as 10 mum could abolish penetration in the SPA provided sperm were prepared by passive incubation. Cells electropermeabilized in the presence of calcium could overcome the DDC block. Exogenous addition of superoxide dismutase and catalase could provide effective protection to sperm against the effects of ultraviolet treatment.
Tomkins
P T
PT
Toxicology Unit, Department of Applied Biology, Regional College, Athlone, Ireland.