engleski

Protection of human spermatozoa from hydrogen peroxide-induced DNA and membrane damage by exogenous gangliosides

We have previously demonstrated the protective effect of gangliosides, the sialic acid containing glycosphingolipids, against sperm injury caused by reactive oxygen species (ROS). The aim of this study was to determine whether exogenously added ganglioside GT1b could protect human spermatozoa from DNA fragmentation and increased apoptosis induced by in vitro exposure to H2O2. Single-cell gel electrophoresis (Comet assay) was used in the assessment of sperm DNA integrity and the transport of H2O2 across the cell membrane and sperm cell viability after exposure to H2O2 were assessed by means of flow cytometry using ROS sensitive fluorescent dichlorodihydrofluorescein diacetate (DCFH-DA) dye and Annexin V in combination with propidium iodide labelling. The obtained results showed that in vitro supplemented GT1b (100 μM) significantly reduced DNA damage induced by 200 μM H2O2 (p<0.05), increased the percentage of live cells with intact membrane (p<0.01) and decreased phosphatidylserine translocation after exposure to H2O2. Flow cytometry revealed that ganglioside GT1b completely inhibited the passage of H2O2 through the sperm membrane. In conclusion, the results gave evidence on the ability of ganglioside GT1b to protect human spermatozoa from H2O2-induced damage. Reduced DNA fragmentation and apoptotic changes due to a decreased H2O2 cell content suggest that ganglioside GT1b, rendering sperm membrane more hydrophobic, acts as an inhibitor of H2O2 diffusion across the sperm membrane.

Human spermatozoa; H2O2; DNA; Gangliosides

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