title: Protective effect of gangliosides on DNA in human spermatozoa exposed to cryopreservation.
abstract: Gangliosides, the sialic acid-containing glycosphyngolipids, are  amphiphilic compounds which in micellar form affect the properties and  functions of a cellular membrane. The aim of this study was to test whether  exogenous gangliosides supplied to cryopreservation media before freezing  could protect sperm cells from cryopreservation-induced DNA damage assessed by  Comet assay. Additionally, to investigate whether gangliosides were also able  to reduce membrane integrity damage, malonaldialdehyde as a measure of lipid  peroxidation and sperm-specific lactate dehydrogenase-C4 activity as an enzyme  marker of sperm membrane leakage were determined. The monosialogangliosides  (GM1) and trisialogangliosides (GT1b) were examined at a concentration of 100  μM, which was above their respective critical micellar concentrations.  Exogenous gangliosides were not found to protect sperm membrane from lipid  peroxidation. However, a freezing-/thawing-induced increase in Comet  parameters was equally significantly prevented by the presence of both GM1 and  GT1b (P < .05), indicating that the ceramide moiety, rather than  the polar groups, is involved in the protective ability of gangliosides. The  observed phenomena suggest that ganglioside micelles could modulate  hydrophobic properties of the sperm membrane responsible for better tolerance  to DNA fragmentation, thus protecting DNA integrity from  cryopreservation-induced damage.
authors.affiliation: Unit of Reproductive Biochemistry and Cell Metabolism, Institute of Clinical Chemistry and Laboratory Medicine, Merkur University Hospital, Dugi Dol 4a, 10000 Zagreb, Croatia. mirjana.gavella@idb.hr
authors.forename: Mirjana
authors.initials: M
authors.lastname: Gavella
authors.forename: Vaskresenija
authors.initials: V
authors.lastname: Lipovac
authors.forename: Verica
authors.initials: V
authors.lastname: Garaj-Vrhovac
authors.forename: Goran
authors.initials: G
authors.lastname: Gajski
mesh_terms: D000328:Adult; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D020552:Comet Assay; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D019610:Cytoprotection; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D005677:G(M1) Ganglioside / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008823:Micelles; D012662:Semen Preservation / Q000379:methods*; D013076:Sperm Count; D013081:Sperm Motility; D053625:Sperm Retrieval; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
chemical_list: D003451:Cryoprotective Agents; D007527:Isoenzymes; D008823:Micelles; D005677:G(M1) Ganglioside; D008315:Malondialdehyde; C029624:ganglioside M1b; D007770:L-Lactate Dehydrogenase; C409673:lactate dehydrogenase C4