Background: In this study we present the physiological changes observed in ejaculated spermatozoa of normospermic men after exposure to hydrogen peroxide (H(2)O(2)) or gamma irradiation.
Methods: Motility changes as well as membrane and DNA-damage were determined in spermatozoa after incubation with 25 micromol/l of H(2)O(2) during increasing intervals of time (0--60 min and after 24 h) or after irradiation of cells using alpha rays. Annexin V-binding in combination with propidium iodide was used for the assessment of membrane changes after each incubation time. TdT-mediated-dUTP nick-end labelling (TUNEL) was used to evaluate DNA damage.
Results: After 1 h incubation of the spermatozoa with H(2)O(2), almost all cells were positive for Annexin-V, while no significantly increase in TUNEL positivity was observed. TUNEL results were significantly higher 24 h after incubation with H(2)O(2) (10--16.3%, P = 0.03). In the control group (cumulus cells), an increase in the percentage of TUNEL positive cells was observed after 15 min of incubation with H(2)O(2) and showed a five-fold increase after 24 h (from 8.1-72.1%, P < 0.001). TUNEL positive cells after alpha irradiation increased with the doses and post-irradiation time (from 10.8--47.2%). Interestingly, when only motile spermatozoa from irradiated samples were analysed, only 0.5% were TUNEL positive.
Conclusion: Motility may be a relevant physiological marker for DNA-intact sperm after exposure of spermatozoa to H(2)O(2) and alpha irradiation.