title: Mitochondrial oxygen consumption is a unique indicator of stallion spermatozoal health and varies with cryopreservation media.
abstract: Mitochondrial oxygen consumption is a sensitive indicator of spermatozoal health in the context of cryopreservation. We investigated oxygen consumption of equine sperm mitochondria during incubation in four commercially available sperm cryopreservation extenders: modified INRA 96, BotuCrio, EZ Freezin-"LE" and "MFR5", in addition to several other parameters including motility, reactive oxygen species (ROS) production and viability. All experimental endpoints, with the exception of average path velocity, were affected significantly by freezing extender type after freezing and thawing. Sperm in INRA 96 had the lowest average progressive motility after thawing (24 ± 4.8%, P < 0.05). Sperm in EZ Freezin-"LE" had the highest post thaw viability (79 ± 3.1%, P < 0.05) and lowest post thaw ROS production (13 ± 2.4%), but sperm in BotuCrio had the highest maximal oxygen consumption levels, while also demonstrating similar ROS production and viability. This difference would not have been detected using conventional sperm analytical methods. In addition, sperm in BotuCrio had the highest average total motility (49 ± 7.4%), progressive motility (41 ± 6.4%), and velocity (VAP, 90 ± 3.6 μm/s) indicating that this medium preserved mitochondrial function optimally after cryopreservation. Mitochondrial oxygen consumption was positively correlated with traditional measures of sperm function including motility and viability (r = 0.62 and r = 0.49, respectively, P < 0.05), thus making it a sensitive method for determining cryopreservation success and mitochondrial function in stallion sperm.
authors.affiliation: Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, California, USA.
authors.forename: Christa R
authors.initials: CR
authors.lastname: Darr
authors.affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, USA.
authors.forename: Gino A
authors.initials: GA
authors.lastname: Cortopassi
authors.affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, USA.
authors.forename: Sandipan
authors.initials: S
authors.lastname: Datta
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA; Veterinary Medical Teaching Hospital, Texas A&M University, College Station, Texas, USA.
authors.forename: Dickson D
authors.initials: DD
authors.lastname: Varner
authors.affiliation: Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, California, USA. Electronic address: smeyers@ucdavis.edu.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Meyers
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D006736:Horses / Q000502:physiology*; D008297:Male; D008928:Mitochondria / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D055101:Semen Analysis / Q000662:veterinary*; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D003451:Cryoprotective Agents
keywords: Cryopreservation extender; Mitochondria; Sperm; Stallion