Influence of cryopreservation on mitochondrial functions in equine spermatozoa.
Abstract: Cryopreservation of spermatozoa is of essential importance for artificial insemination and breeding programs in horses. Besides other factors, spermatozoal motility depends on mitochondrial energy metabolism. Based on changes of single mitochondrial functions it has been suggested that mitochondrial damage during cryopreservation could be a major reason for diminished post thaw semen quality. However, it is still unclear to which extent this influences the whole bioenergetic performance of mitochondria and whether this plays a role during routine cryopreservation procedures. Therefore, it was the aim of this study to compare changes in mitochondrial bioenergetics in spermatozoa during shock freezing and routine cryopreservation. Mitochondrial integrity in spermatozoa was studied by determination of oxygen consumption, mitochondrial membrane potential, and the oxidation of externally added cytochrome c(2+). Shock freezing of spermatozoa resulted in an irreversible loss of mitochondrial functions. However, respiration difference of uncoupled minus resting state and routine respiration also decreased by 48+/-14 and 58+/-6% (p<0.05), respectively, after routine cryopreservation. This was accompanied by a decline in the mitochondrial membrane potential to 83+/-4% (p<0.05) and spermatozoal motility to 56+/-11% (p<0.05) of pre-freezing values. In contrast, the oxidation rates of externally added cytochrome c(2+) by cytochrome c oxidase slightly increased by 26+/-14% (p<0.1) suggesting a partial rupture of cellular and outer mitochondrial membranes. Our data indicate that also widely used cryopreservation protocols for equine spermatozoa need adjustment to optimize post thaw mitochondrial functions.
Publication Date: 2007-07-17 PubMed ID: 17644168DOI: 10.1016/j.theriogenology.2007.06.004Google Scholar: Lookup
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Summary
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The research article presents a study about how the process of cryopreservation (freezing) affects the mitochondrial functions in horse sperm, a critical component of artificial insemination and breeding programs.
Research Objectives and Background
- The research aimed to examine the impact of cryopreservation on mitochondrial functions in horse spermatozoa.
- Given the significant role that mitochondria play in spermatozoal motility, the research hypothesized that damage to mitochondria during the freezing process could limit the quality of sperm after thawing.
- The potential changes in overall mitochondrial bioenergetics performance were examined across two variables: shock freezing and routine cryopreservation.
Research Methods
- The researchers assessed mitochondrial integrity within spermatozoa by studying oxygen consumption, mitochondrial membrane potential, and the oxidation of externally added cytochrome c(2+).
- Through these assessments, the research could identify potential loss of mitochondrial functions after shock freezing of spermatozoa.
Research Findings
- The study found that shock freezing resulted in permanent loss of mitochondrial functions.
- After routine cryopreservation, researchers reported a significant drop in resting and routine respiration, mitochondrial membrane potential, and spermatozoal motility.
- The study also revealed that the oxidation rates of externally added cytochrome c(2+) increased incrementally, suggesting a partial rupture of the cellular and outer mitochondrial membranes.
Implications and Conclusion
- The researchers concluded that even widely accepted cryopreservation protocols impact mitochondrial functions in horse spermatozoa, negatively affecting their post-thaw performance.
- Based on their findings, the researchers suggested that those protocols need to be adjusted to maintain or optimize mitochondrial functionality after thawing.
- The research helps lay a foundation for improving current freezing protocols to safeguard mitochondrial integrity, ultimately improving the quality of frozen-thawed sperm for artificial insemination and equine breeding programs.
Cite This Article
APA
Schober D, Aurich C, Nohl H, Gille L.
(2007).
Influence of cryopreservation on mitochondrial functions in equine spermatozoa.
Theriogenology, 68(5), 745-754.
https://doi.org/10.1016/j.theriogenology.2007.06.004 Publication
Researcher Affiliations
- Molecular Pharmacology and Toxicology Unit, Department of Natural Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210, Vienna, Austria.
MeSH Terms
- Animals
- Cell Respiration / physiology
- Cryopreservation
- Cytochromes c2 / metabolism
- Horses
- Male
- Membrane Potential, Mitochondrial / physiology
- Mitochondria / metabolism
- Mitochondria / physiology
- Semen Preservation / adverse effects
- Spermatozoa / metabolism
- Spermatozoa / physiology
Citations
This article has been cited 9 times.- Strassner FM, Demattio L, Siuda M, Malama E, Muffels G, Bollwein H. Relationships Between Metabolism of Cryopreserved Equine Sperm Determined by the Seahorse Analyzer and Sperm Characteristics Measured by Flow Cytometry and Computer-Assisted Analysis of Motility. Vet Sci 2025 Nov 21;12(12).
- Ullah A, Chen W, Shi L, Wang M, Geng M, Na J, Akhtar MF, Khan MZ, Wang C. Challenges and Enhancing Strategies of Equine Semen Preservation: Nutritional and Genetic Perspectives. Vet Sci 2025 Aug 25;12(9).
- Al-Kass Z, Morrell JM, Ntallaris T. Effect of Centrifugation of Stallion Semen Through a Low Density Colloid Prior to Freezing on Sperm Cryosurvival. Animals (Basel) 2025 Jun 25;15(13).
- Mendoza N, Casao A, Domingo J, Quintín F, Laviña A, Fantova E, Cebrián-Pérez JÁ, Muiño-Blanco T, Pérez-Pe R. Influence of Non-conventional Sperm Quality Parameters on Field Fertility in Ovine. Front Vet Sci 2021;8:650572.
- Aurich J, Kuhl J, Tichy A, Aurich C. Efficiency of Semen Cryopreservation in Stallions. Animals (Basel) 2020 Jun 13;10(6).
- Castro LS, Hamilton TR, Mendes CM, Nichi M, Barnabe VH, Visintin JA, Assumpção ME. Sperm cryodamage occurs after rapid freezing phase: flow cytometry approach and antioxidant enzymes activity at different stages of cryopreservation. J Anim Sci Biotechnol 2016;7:17.
- de Castro LS, de Assis PM, Siqueira AF, Hamilton TR, Mendes CM, Losano JD, Nichi M, Visintin JA, Assumpção ME. Sperm Oxidative Stress Is Detrimental to Embryo Development: A Dose-Dependent Study Model and a New and More Sensitive Oxidative Status Evaluation. Oxid Med Cell Longev 2016;2016:8213071.
- Birk AV, Chao WM, Bracken C, Warren JD, Szeto HH. Targeting mitochondrial cardiolipin and the cytochrome c/cardiolipin complex to promote electron transport and optimize mitochondrial ATP synthesis. Br J Pharmacol 2014 Apr;171(8):2017-28.
- Madeddu M, Berlinguer F, Ledda M, Leoni GG, Satta V, Succu S, Rotta A, Pasciu V, Zinellu A, Muzzeddu M, Carru C, Naitana S. Ejaculate collection efficiency and post-thaw semen quality in wild-caught Griffon vultures from the Sardinian population. Reprod Biol Endocrinol 2009 Feb 19;7:18.
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