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Home / Equine Research Bank / Vet Sci / Addition of Reduced Glutathione (GSH) to Freezing Medium Red...
Veterinary sciences2021; 8(12); doi: 10.3390/vetsci8120302

Addition of Reduced Glutathione (GSH) to Freezing Medium Reduces Intracellular ROS Levels in Donkey Sperm.

Abstract: In donkeys, the use of frozen-thawed sperm for artificial insemination (AI) leads to low fertility rates. Furthermore, donkey sperm produce a large amount of reactive oxygen species (ROS), and post-AI inflammation induces the formation of neutrophil extracellular traps (NETosis), which further generates many more ROS. These high ROS levels may induce lipid peroxidation in the sperm plasma membrane, thus affecting its integrity. Enzymatic and non-enzymatic antioxidants, mainly found in the seminal plasma (SP), are responsible for maintaining the redox balance. However, this fluid is removed prior to cryopreservation, thereby exposing sperm cells to further oxidative stress. The exogenous addition of antioxidants to the freezing medium can reduce the detrimental effects caused by ROS generation. Therefore, the aim of this study was to evaluate how the addition of different reduced glutathione (GSH) concentrations (control, 2 mM, 4 mM, 6 mM, 8 mM, and 10 mM) to fresh sperm affect their cryotolerance. Total and progressive motility, kinematic parameters and motile sperm subpopulations were significantly (p < 0.05) different from the control in treatments containing 8 mM and 10 mM GSH, but not at lower concentrations. Plasma and acrosome membrane integrity, mitochondrial membrane potential (MMP) and intracellular superoxide levels (O2-) were not affected (p > 0.05) by any GSH concentration. Interestingly, however, the addition of 8 mM or 10 mM GSH reduced (p < 0.05) the percentages of viable sperm with high overall ROS levels compared to the control. In conclusion, frozen-thawed donkey sperm are able to tolerate high GSH concentrations, which differs from what has been observed in other species. This antioxidant capacity suggests that ROS could be important during post-AI and that the impact of using exogenous antioxidants like GSH to improve the sperm resilience to freeze-thawing is limited in this species.
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Publication Date: 2021-12-02 PubMed ID: 34941829PubMed Central: PMC8703656DOI: 10.3390/vetsci8120302Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article studies the effect of adding reduced glutathione (GSH) to frozen sperm in donkeys to improve their fertility rate. The focus is on diminishing the negative impacts of reactive oxygen species (ROS) generated during artificial insemination (AI), especially during cryopreservation.

Research Context

  • The article addresses the low fertility rates following artificial insemination in donkeys using frozen-thawed sperm. This lower fertility rate is due to the high amount of reactive oxygen species (ROS) that donkey sperm produce and the subsequent inflammatory response post-AI, producing even more ROS. Excessive ROS causes lipid peroxidation in the sperm plasma membrane, thus damaging the integrity of the sperm.
  • Antioxidants typically present in the seminal plasma maintain the redox balance, helping to counteract the harmful effects of ROS, but this fluid is removed before cryopreservation, leading to an increase in oxidative stress. The researchers hypothesized that the introduction of additional exogenous antioxidants to the freezing medium could help to mitigate these effects.

Methodology

  • The research tested the theory by adding varying quantities of the antioxidant reduced glutathione (GSH) to fresh sperm.
  • The different GSH concentrations (control, 2 mM, 4 mM, 6 mM, 8 mM, and 10 mM) were studied to observe how they influence the resilience of the sperm during freezing.
  • The effects on total and progressive motility, kinematic parameters and motile sperm subpopulations, plasma and acrosome membrane integrity, mitochondrial membrane potential (MMP), and intracellular superoxide levels were all considered.

Findings

  • Sperm treated with 8 mM and 10 mM GSH demonstrated significantly different results in terms of motility, kinematic parameters and motile sperm subpopulations compared to the control group.
  • The integrity of the plasma and acrosome membranes, the mitochondrial membrane potential, and the intracellular superoxide levels did not show any noticeable difference with varying GSH concentrations.
  • However, the percentage of viable sperm with high overall ROS levels was seen reduced with the addition of 8 mM or 10 mM of GSH.
  • Unlike other species, frozen-thawed donkey sperm seem to tolerate high GSH concentrations, suggesting the significance of ROS during post-AI and the limited impact of using exogenous antioxidants such as GSH to enhance sperm resistance to freezing and thawing processes.

Cite This Article

APA
Yánez-Ortiz I, Catalán J, Delgado-Bermúdez A, Carluccio A, Miró J, Yeste M. (2021). Addition of Reduced Glutathione (GSH) to Freezing Medium Reduces Intracellular ROS Levels in Donkey Sperm. Vet Sci, 8(12). https://doi.org/10.3390/vetsci8120302

Publication

Veterinary sciences
ISSN: 2306-7381
NlmUniqueID: 101680127
Country: Switzerland
Language: English
Volume: 8
Issue: 12

Researcher Affiliations

Yánez-Ortiz, Iván
  • Equine Reproduction Service, Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Autonomous University of Barcelona, ES-08193 Barcelona, Cerdanyola del Vallès, Spain.
  • Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain.
  • Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain.
Catalán, Jaime
  • Equine Reproduction Service, Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Autonomous University of Barcelona, ES-08193 Barcelona, Cerdanyola del Vallès, Spain.
  • Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain.
  • Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain.
  • Faculty of Veterinary Medicine, University of Teramo, Loc. Piano d'Accio, IT-64100 Teramo, Italy.
Delgado-Bermúdez, Ariadna
  • Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain.
  • Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain.
Carluccio, Augusto
  • Faculty of Veterinary Medicine, University of Teramo, Loc. Piano d'Accio, IT-64100 Teramo, Italy.
Miró, Jordi
  • Equine Reproduction Service, Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, Autonomous University of Barcelona, ES-08193 Barcelona, Cerdanyola del Vallès, Spain.
Yeste, Marc
  • Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain.
  • Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain.

Conflict of Interest Statement

The authors declare no conflict of interest.

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