Apoptotic-like changes in equine spermatozoa separated by density-gradient centrifugation or after cryopreservation

• Published in: Theriogenology 2008-06, Vol.69 (9), p.1041-1055
• Main Authors: Brum, A.M., Sabeur, K., Ball, B.A.
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Apoptosis - physiology; biomarkers; Caspases; cell membranes; Cell Survival - physiology; centrifugation; Centrifugation, Density Gradient - veterinary; Cryopreservation; Cryopreservation - veterinary; density-gradient centrifugation; DNA fragmentation; Equine; Flow cytometry; Horses - physiology; Male; membrane permeability; membrane potential; mitochondria; Quality Control; Semen Preservation - veterinary; Sperm Motility; Spermatozoa; Spermatozoa - cytology; Spermatozoa - physiology; stallions
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2008.01.014

The objective was to evaluate apoptotic markers in ejaculated equine spermatozoa after separation by density-gradient centrifugation and after cryopreservation. Subpopulations of percoll-separated equine spermatozoa differed ( P < 0.05) in the percentage of live, caspase-activated spermatozoa (2.9 ± 0.7% vs 14.2 ± 6.4%; mean ± S.E.M.), low mitochondrial membrane potential (MMP; 6.8 ± 1.1 vs 23.8 ± 3.7), altered plasma membrane permeability (1.3 ± 0.2 vs 3.0 ± 0.5), DNA fragmentation (2.0 ± 1.3 vs 14.3 ± 3.6), total motility (81.8 ± 3.3 vs 35.1 ± 5.4), and progressive motility (66.3 ± 4.3 vs 24.1 ± 4.5) for high-density versus low-density subpopulations, respectively. Phosphatidylserine externalization did not differ ( P = 0.67) between the high- and low-density subpopulations (2.6 ± 0.7 vs 3.1 ± 0.9). After cryopreservation, equine spermatozoa differed ( P < 0.01) in the percentage of active caspases (19.1 ± 1.6 vs 52.1 ± 2.8), low MMP (18.2 ± 2.5 vs 48.7 ± 2.6), altered plasma membrane permeability (6.8 ± 1.7 vs 17.6 ± 2.0), total motility (75.5 ± 2.4 vs 45.2 ± 5.6), and progressive motility (53.9 ± 3.1 vs 28.3 ± 4.5) for pre-freeze versus cryopreserved spermatozoa. There was no difference ( P = 0.21) in percentage of DNA fragmented cells before (5.5 ± 1.2) versus after cryopreservation (6.6 ± 1.1). We concluded that apoptotic-like changes were detectable in ejaculated equine spermatozoa and were more prevalent after cryopreservation.