Addition of antioxidants improves quality of cooled stored stallion semen.

Perhaps another step- towards more successful cooled semen and sperm preservation and possible applications to frozen semen. Still missing are fertilization rates but this first step looks promising.
DrO

Anim Reprod Sci. 2019 Nov;210:106195.
Combined addition of superoxide dismutase, catalase and glutathione peroxidase improves quality of cooled stored stallion semen.
Del Prete C1, Stout T2, Montagnaro S3, Pagnini U3, Uccello M4, Florio P4, Ciani F3, Tafuri S3, Palumbo V3, Pasolini MP3, Cocchia N3, Henning H2.

Author information:
1. Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino, 1, 80137, Napoli, Italy. Electronic address: chiara.delprete@unina.it.
2. Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, the Netherlands.
3. Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino, 1, 80137, Napoli, Italy.
4. Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Napoli, Italy.
Abstract

During cold storage stallion spermatozoa experience undergo oxidative stress, which can impair sperm function and fertilizing capacity. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) are the main endogenous enzymatic antioxidants in stallion seminal plasma, and counteract reactive oxygen species. Semen dilution reduces the endogenous antioxidant concentrations. The aim of this study was to investigate whether addition of 15 IU/mL each of SOD, CAT, and GPX to diluted stallion semen would ameliorate a reactive oxygen-mediated decrease in semen quality during 72 h of storage at 5 °C. Ejaculates (n = 7) were divided in two aliquots and diluted in INRA 96 without (control) or with addition of antioxidants. Semen analysis was performed at the time of dilution and every 24 h during chilled storage. Antioxidant supplementation completely inhibited the storage-dependent increase in activated caspase 3 (P < 0.05). Concomitantly, the antioxidant-supplemented samples had a greater percentage of viable, motile and rapidly moving sperm than control samples after 72 h storage (P < 0.05). The DNA damage, as evaluated by TUNEL assay and SCSA, increased with storage time (P < 0.05). Antioxidant supplementation did not prevent, but did significantly reduce the increase in DNA strand breakage. The results indicate part of the intrinsic apoptotic pathway leading to effector caspase activation was inhibited, although an activation of molecules with endonuclease activity still occurred. In conclusion, adding equal concentrations of SOD, CAT and GPX to a semen extender suppressed caspase-3 activation and improved preservation of stallion sperm motility and viability during 72 h of storage at 5 °C.