title: Reduced glutathione and procaine hydrochloride protect the nucleoprotein structure of boar spermatozoa during freeze-thawing by stabilising disulfide bonds.
abstract: One important change the head of boar spermatozoa during freeze-thawing is the destabilisation of its nucleoprotein structure due to a disruption of disulfide bonds. With the aim of better understanding these changes in frozen-thawed spermatozoa, two agents, namely reduced glutathione (GSH) and procaine hydrochloride (ProHCl), were added at different concentrations to the freezing media at different concentrations and combinations over the range 1-2mM. Then, 30 and 240 min after thawing, cysteine-free residue levels of boar sperm nucleoproteins, DNA fragmentation and other sperm functional parameters were evaluated. Both GSH and ProHCl, at final concentrations of 2mM, induced a significant (P<0.05) increase in the number of non-disrupted sperm head disulfide bonds 30 and 240 min after thawing compared with the frozen-thawed control. This effect was accompanied by a significant (P<0.05) decrease in DNA fragmentation 240 min after thawing. Concomitantly, 1 and 2mM GSH, but not ProHCl at any of the concentrations tested, partially counteracted the detrimental effects caused by freeze-thawing on sperm peroxide levels, motility patterns and plasma membrane integrity. In conclusion, the results show that both GSH and ProHCl have a stabilising effect on the nucleoprotein structure of frozen-thawed spermatozoa, although only GSH exerts an appreciable effect on sperm viability.
authors.affiliation: Unit of Animal Reproduction, Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Autonomous University of Barcelona, 08193 Bellaterra, Barcelona, Spain. marc.yeste@uab.cat
authors.forename: Marc
authors.initials: M
authors.lastname: Yeste
authors.forename: Eva
authors.initials: E
authors.lastname: Flores
authors.forename: Efrén
authors.initials: E
authors.lastname: Estrada
authors.forename: Sergi
authors.initials: S
authors.lastname: Bonet
authors.forename: Teresa
authors.initials: T
authors.lastname: Rigau
authors.forename: Joan E
authors.initials: JE
authors.lastname: Rodríguez-Gil
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods; D003545:Cysteine / Q000032:analysis / Q000737:chemistry; D053938:DNA Fragmentation; D004220:Disulfides / Q000737:chemistry; D004355:Drug Stability; D005609:Free Radicals / Q000032:analysis; D005978:Glutathione / Q000494:pharmacology*; D006358:Hot Temperature; D008297:Male; D008563:Membrane Lipids / Q000032:analysis; D009698:Nucleoproteins / Q000737:chemistry*; D010545:Peroxides / Q000032:analysis; D011343:Procaine / Q000494:pharmacology*; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000737:chemistry* / Q000187:drug effects; D013481:Superoxides / Q000032:analysis; D013552:Swine
chemical_list: D004220:Disulfides; D005609:Free Radicals; D008563:Membrane Lipids; D009698:Nucleoproteins; D010545:Peroxides; D013481:Superoxides; D011343:Procaine; D005978:Glutathione; D003545:Cysteine