Mitochondria, fundamental organelles in cell metabolism, and ATP synthesis are responsible for generating reactive oxygen species (ROS), calcium homeostasis, and cell death. Mitochondria produce most ROS, and when levels exceed the antioxidant defenses, oxidative stress (OS) is generated. These changes may eventually impair the electron transport chain, resulting in decreased ATP synthesis, increased ROS production, altered mitochondrial membrane permeability, and disruption of calcium homeostasis. Mitochondria play a key role in the gamete competence to facilitate normal embryo development. However, iatrogenic factors in assisted reproductive technologies (ART) may affect their functional competence, leading to an abnormal reproductive outcome. Cryopreservation, a fundamental technology in ART, may compromise mitochondrial function leading to elevated intracellular OS that decreases sperm and oocytes’ competence and the dynamics of fertilization and embryo development. This article aims to review the role played by mitochondria and ROS in sperm and oocyte function and the close, biunivocal relationships between mitochondrial damage and ROS generation during cryopreservation of gametes and gonadal tissues in different species. Based on current literature, we propose tentative hypothesis of mechanisms involved in cryopreservation-associated mitochondrial dysfunction in gametes, and discuss the role played by antioxidants and other agents to retain the competence of cryopreserved reproductive cells and tissues.

Mitochondrial Dysfunction and Oxidative Stress Caused by Cryopreservation in Reproductive Cells.

Lipid metabolic disorders due to poor eating habits are on the rise in both developed and developing countries, with a negative impact of the "Western diet" on sperm count and quality. Dietary lipid imbalance can involve cholesterol, fatty acids, or both, under different pathophysiological conditions grouped under the term dyslipidemia. The general feature of dyslipidemia is the development of systemic oxidative stress, a well-known deleterious factor for the quality of male gametes and associated with infertility. Sperm are particularly rich in polyunsaturated fatty acids (PUFA), an important characteristic associated with normal sperm physiology and reproductive outcomes, but also targets of choice for oxidative thrust. This review focuses on the effects of dietary cholesterol or different fatty acid overload on sperm composition and function in both animals and humans. The links between oxidative stress induced by dyslipidemia and sperm dysfunction are then discussed, including possible preventive or therapeutic strategies to preserve gamete quality, longevity when stored in cryobanking, and male fertility.

/pdf/dietary-cholesterol-and-lipid-overload-impact-on-male-363e97gy08.pdf

Dietary Cholesterol and Lipid Overload: Impact on Male Fertility

Simple Summary Here we present a comprehensive review of the current literature describing mechanisms of damage incurred by cryopreservation, and we highlight several classical and novel strategies to mitigate this damage and increase sperm survival during the cryopreservation process. Abstract Cryopreservation is a way to preserve germplasm with applications in agriculture, biotechnology, and conservation of endangered animals. Cryopreservation has been available for over a century, yet, using current methods, only around 50% of spermatozoa retain their viability after cryopreservation. This loss is associated with damage to different sperm components including the plasma membrane, nucleus, mitochondria, proteins, mRNAs, and microRNAs. To mitigate this damage, conventional strategies use chemical additives that include classical cryoprotectants such as glycerol, as well as antioxidants, fatty acids, sugars, amino acids, and membrane stabilizers. However, clearly current protocols do not prevent all damage. This may be due to the imperfect function of antioxidants and the probable conversion of media components to more toxic forms during cryopreservation.

/pdf/cryopreservation-of-semen-in-domestic-animals-a-review-of-1y5bbtvd.pdf

Cryopreservation of Semen in Domestic Animals: A Review of Current Challenges, Applications, and Prospective Strategies

Nano-range bioactive colloidal carrier systems are envisaged to overcome the challenges associated with treatments of numerous diseases. Lipid nanoparticles (LNPs), one of the extensively investigated drug delivery systems, not only improve pharmacokinetic parameters, transportation, and chemical stability of encapsulated compounds but also provide efficient targeting and reduce the risk of toxicity. Over the last decades, nature-derived polyphenols, vitamins, antioxidants, dietary supplements, and herbs have received more attention due to their remarkable biological and pharmacological health and medical benefits. However, their poor aqueous solubility, compromised stability, insufficient absorption, and accelerated elimination impede research in the nutraceutical sector. Owing to the possibilities offered by various LNPs, their ability to accommodate both hydrophilic and hydrophobic molecules and the availability of various preparation methods suitable for sensitive molecules, loading natural fragile molecules into LNPs offers a promising solution. The primary objective of this work is to explore the synergy between nature and nanotechnology, encompassing a wide range of research aimed at encapsulating natural therapeutic molecules within LNPs.

Lipid Nanoparticles: An Effective Tool to Improve the Bioavailability of Nutraceuticals

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9968670

Tenofovir antiviral drug solubility enhancement with β-cyclodextrin inclusion complex and in silico study of potential inhibitor against SARS-CoV-2 main protease (Mpro)

Background During cryopreservation sperm cells suffer from two major deleterious impacts: oxidative stress and cold shock. Objective To investigate in bovine species the benefit of cholesterol and vitamin E, both loaded in cyclodextrins, as a double protection against oxidative stress and cold shock. Materials and methods Semen was collected from nine mature bulls using an artificial vagina and each ejaculate was split into four equal aliquots. The control aliquot was diluted with Fraction A (Tris+citric acid+fructose+penicillin) without further supplementation; the treated samples were diluted in Fraction A supplemented with cholesterol-loaded cyclodextrins (CD-CHL), vitamin E-loaded cyclodextrins (CD-Vit E) or CD-CHL in association with CD-Vit E (CD-CHL-VitE). After incubation at 22°C for 15 min and addition of Fraction B (Fraction A+egg yolk+glycerol), all aliquots were frozen in 0.25 ml straws. Straws were then thawed individually at 37C for 30 seconds in a water bath and immediately analyzed for motility, using Computer Aided Semen Analysis (CASA), membrane integrity and oxidative stress status. Results The results showed that samples treated with CD-CHL and CD-Vit E were protected against the deleterious impact of freezing thawing process. However, the optimal protection was observed when the two complexes CD-CHL and CD-Vit E were simultaneously used. All analysed semen parameters including motility, membrane integrity and oxidative stress status were significantly improved in CD-CHL-Vit E compared to all other treatments. Conclusion Cholesterol and vitamin E, both preloaded in cyclodextrins to increase their solubility, appeared as a powerful protection in cryopreserved bovine semen to fight simultaneously cold shock and oxidative stress.

The Complementary Effect of Cholesterol and Vitamin E Preloaded in Cyclodextrins on Frozen Bovine Semen: Motility Parameters, Membrane Integrity and Lipid Peroxidation.

BACKGROUND
It is known that a considerable number of drugs in clinical use or under development are water-insoluble drugs with poor bioavailability. The liposomal delivery system has drawn attention as one of the noteworthy approaches to increase both dissolution and absorption because of its biocompatibility and ability to encapsulate hydrophobic molecules in the lipid domain. However, several drawbacks have been reported, the most common is liposome structural instability.


OBJECTIVE
To encapsulate alpha tocopherol into liposomes, to determine the new formulation stability and to study the drug-release of alpha tocopherol into the sperm cryopreservation medium.


MATERIALS AND METHODS
The liposomes prepared by an ethanol injection method were characterized for size stability, alpha tocopherol release and sperm motility tests.


RESULTS
The prepared unilamellar vesicles had both narrow size distribution (around 99 nm) and a good physical and chemical stability at 4°C during 12 months. The liposomes did not release the vitamin E immediately, but retained the protectant for 24 hours, probably due to the rigidity of the liposomal fence which was reinforced by adding cholesterol. Then, all vitamin E molecules were released by 48 hours. Release was potentially by Fickian diffusion probably by the creation of mini-ducts due to both agitation and fence hydration. Moreover, semen motility treated with vitamin E liposome preparations was significantly improved compared to all other treatments (including commonly used sperm conservation media).


CONCLUSION
The stable vitamin E liposomes formulated in this work are a promising alternative for semen cryopreservation protection.

Drug release, stability and efficiency of vitamin e loaded in liposomes for bovine sperm protection in cryopreservation medium.

Background Rosmarinus officinalis essential oil (Rom) has been reported recently to be of interest for use in sperm cryopreservation. However, related to its lipophilic characteristics, encapsulation in cyclodextrin could enhance Rom positive effects by increasing its solubility in sperm extenders. Objective To compare the effect of Rom preloaded in hydroxypropyl-β-cyclodextrin (Rom-cd) to Rom alone (Rom) on ram sperm conserved at 4°C. Materials and methods Ram epididymal sperm was collected from six testes. Each collected sperm was split into four equal aliquots. The control aliquot was diluted with Tris extender (Tris + citric acid + fructose + penicillin), two aliquots were treated with Rom at 0.5µl ml-1 and 1µl ml-1 respectively, and one aliquot treated with Rom-cd at 1µl ml-1. All sperm aliquots were analyzed for motility after 0, 2, 4, 24 and 48 h of storage at 4°C using a Computer Aided Semen Analysis (CASA). Membrane integrity and oxidative stress status were measured after 48 h of storage. Results The results indicated that motility parameters were best preserved in the extender containing Rom-cd compared to the groups treated by Rom without cyclodextrin. Rom alone resulted to higher sperm motility than the control group. Lower oxidative stress and more cell membrane protection were observed in Rom treated samples, especially when using Rom-cd. Conclusion The ability of Rom to protect ram sperm against cryopreservation damages was improved after encapsulation in hydroxypropyl-β-cyclodextrin (HPβCD).

Rosmarinus officinalis Essential Oil Preloaded in β-Cyclodextrin: Effect on Ram Spermatozoa Motility, Membrane Integrity and Oxidative Status During 4°C Storage.

Reproduction Activity of Flathead Mullet Mugil cephalus (Linnaeus, 1758) in Wild Condition in the Northeast of Algeria

The Presence of Vitamin C Enhances the Protection of Cholesterol-cyclodextrin and Vitamin E-cyclodextrin in Cryopreservation of Bull Semen

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