Ganglioside GT1b protects human spermatozoa from hydrogen peroxide-induced DNA and membrane damage

Abstract

We have reported previously that various gangliosides, the sialic acid containing glycosphingolipids, provide protection against sperm injury caused by reactive oxygen species (ROS). In this study, we investigated the effect of treatment of human spermatozoa with ganglioside GT1b on hydrogen peroxide (H2O2)-induced DNA fragmentation and plasma membrane damage. Single-cell gel electrophoresis (Comet assay) used in the assessment of sperm DNA integrity showed that in vitro supplemented GT1b (100 μm) significantly reduced DNA damage induced by H2O2 (200 μm) (p < 0.05). Measurements of Annexin V binding in combination with the propidium iodide vital dye labelling demonstrated that the spermatozoa pre-treated with GT1b exhibited a significant increase (p < 0.05) in the percentage of live cells with intact membrane and decreased phosphatidylserine translocation after exposure to H2O2. Flow cytometry using the intracellular ROS-sensitive fluorescence dichlorodihydrofluorescein diacetate dye employed to investigate the transport of the extracellularly supplied H2O2 into the cell interior revealed that ganglioside GT1b completely inhibited the passage of H2O2 through the sperm membrane. These results suggest that ganglioside GT1b may protect human spermatozoa from H2O2-induced damage by rendering sperm membrane more hydrophobic, thus inhibiting the diffusion of H2O2 across the membrane. © 2010 European Academy of Andrology.