Combined addition of superoxide dismutase, catalase and glutathione peroxidase improves quality of cooled stored stallion semen

Antioxidant Activity and Seasonal Variations in the Composition of Insoluble Fiber from the Cladodes of Opuntia ficus-indica (L.) Miller: Development of New Extraction Procedures to Improve Fiber Yield

Opuntia ficus-indica (L.) Miller is a plant belonging to the Cactaceae family adapted to live in environments characterized by long periods of drought and arid or desert climates. This plant is characterized by an aerial part composed of structures transformed by branches, called "cladodes", which are essential to reduce excessive perspiration of water and appear covered with thorns. The composition of the cladodes includes water, polysaccharides, fiber, proteins, vitamins, fatty acids, sterols, polyphenols, and minerals. The main purposes of this scientific work are (a) to compare the insoluble fiber (IF) extracted from the cladodes of O. ficus-indica belonging to the same plant but collected in different seasonal periods (winter and summer) and develop new extraction protocols that are able to improve the yield obtained and (b) evaluate the antioxidant potential of the fiber and study possible variations as a result of the extraction protocol chosen. The first objective was achieved (1) by measuring the amount of IF extracted from cladodes harvested in winter and summer (CW and CS, respectively) and (2) by modifying three variables involved in the fiber extraction protocol. To achieve the second objective, the following experiments were carried out: (1) measurement of the antioxidant potential of IF in CW and CS; (2) measurement of cellular reactive oxygen species; (3) measurement of the activity of some antioxidant enzymes; and (4) comparison of the polyphenol content in CW and CS. In conclusion, the results obtained showed that the IF extraction process can be improved, achieving a uniform yield regardless of seasonality; the antioxidant effect may vary depending on the extraction protocol.

Supplementation of Schisandrin B in Semen Extender Improves Quality and Oxidation Resistance of Boar Spermatozoa Stored at 4 °C

During cold storage, boar spermatozoa undergo oxidative stress, which can impair sperm function and fertilizing capacity. The objective of the present study was to assess the effects of Schisandrin B (Sch B) in semen extenders on the quality of boar semen stored at hypothermia. Semen was collected from twelve Duroc boars and diluted in extenders supplemented with different concentrations of Sch B (0 μmol/L, 2.5 μmol/L, 5 μmol/L, 10 μmol/L, 20 μmol/L, and 40 μmol/L). Here, we demonstrated that 10 μmol/L Sch B provided the best effects on motility, plasma membrane integrity, acrosome integrity, sperm normality rate, average movement velocity, wobbility, mitochondrial membrane potential (MMP), and DNA integrity of sperm. The results of Sch B effects on antioxidant factors in boar sperm showed that Sch B significantly elevated the total antioxidant capacity (T-AOC) and markedly decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) content of sperm. The expression of catalase (CAT) and superoxide dismutase (SOD) mRNA was increased, while the expression of glutathione peroxidase (GPx) mRNA demonstrated no change compared to non-treated boar sperm. Compared to the non-treated group, Sch B triggered a decrease in Ca²⁺/protein kinase A (PKA) and lactic acid content in boar sperm. Similarly, Sch B led to a statistically higher quantitative expression of AWN mRNA and a lower quantitative expression of porcine seminal protein I (PSP-I) and porcine seminal protein II (PSP-II) mRNA. In a further reverse validation test, no significant difference was observed in any of the parameters, including adhesion protein mRNA, calcium content, lactic acid content, PKA, and protein kinase G (PKG) activity after sperm capacitation. In conclusion, the current study indicates the efficient use of Sch B with a 10 μmol/L concentration in the treatment of boar sperm through its anti-apoptosis, antioxidative, and decapacitative mechanisms, suggesting that Sch B is a novel candidate for improving antioxidation and decapacitation factors in sperm in liquid at 4 °C.

In vitro aging of stallion spermatozoa during prolonged storage at 5°C

Artificial insemination with chilled stallion semen is hampered by a limited period of maximum fertility maintenance (24-48 h). This study used multiparametric flow cytometry to simultaneously measure reactive oxygen species (ROS) production, mitochondrial function or [Ca²⁺ ]_i and plasma membrane fluidity in viable, acrosome-intact spermatozoa, with the aim of providing insight into changes in sperm function during storage at 5°C. High proportions of viable and acrosome-intact spermatozoa (71 ± 8%) remained after 96 h of storage demonstrating that the basic integrity of the cells was well preserved (n = 17 stallions). In addition, more than 90% of viable, acrosome-intact spermatozoa had active mitochondria and low intra-cellular or mitochondrial ROS levels. By contrast, the percentage of viable, acrosome-intact sperm with low plasma membrane fluidity and low [Ca²⁺ ]_i decreased over time (1 h: 63 ± 16%, 96 h: 29 ± 18%; p < 0.05). The [Ca²⁺ ]_i in viable sperm rose 3.1-fold (p < 0.05) over the 4 days, and fewer spermatozoa responded to bicarbonate stimulation (1 h: 46 ± 17%, 96 h: 19 ± 12%) with an increase in plasma membrane fluidity following prolonged storage. Overall, prolonged storage of stallion semen at 5°C resulted in disturbed calcium homeostasis and increased plasma membrane fluidity. The decline in fertility of stallion semen during cooled-storage may therefore relate to aspects of in vitro aging (changes in plasma membrane fluidity and intracellular calcium) which impairs capacitation-associated cell functions.

Effects of Oral Administration of Lepidium meyenii on Morphology of Mice Testis and Motility of Epididymal Sperm Cells After Tetrahydrocannabinol Exposure

Background: Tetrahydrocannabinol (THC) administration is associated with testicular damage and reduced semen quality. Oral administration of Lepidium Meyenii (maca) improves spermatogenesis and sperm motility and count and reduces spermatogenic damage. Objectives: The aim of this study was to evaluate the effect of administration of THC, maca, and their combination on testicular tissue and semen parameters. Materials and Methods: Thirty-six-week-old male mice were classified into control, THC, Maca, and THC + Maca groups. The mice were subjected to Eco Color Doppler ultrasound examination of the testicles before and after treatment. After euthanasia, the epididymis, testes, liver, and kidney were collected for histological examination. For morphometry of the testis, tubular diameters and seminiferous epithelium height were measured. Sperm concentration and sperm motilities were assessed. Differences among the groups were assessed using the Kruskal-Wallis and Dunn's post-hoc test. Results: In all the groups, there were no significant changes in testicular morphology before and after treatment. Histological assessment of the testes showed no alterations in control, no significant alterations in Maca, mild to moderate alterations in THC, and mild alterations in THC + Maca groups. Histological examination of the other organs showed no significant differences among the groups. Tubular diameter showed significantly increased thickening for THC and THC + Maca compared with that for Maca and control. Moreover, seminiferous epithelium height decreased for THC compared with that in the control, Maca, and THC + Maca groups. No statistically significant reduction in the spermatogenic index was observed for THC compared with that for Maca and THC + Maca. Epididymal cross-sections of the groups showed no significant alterations. Sperm concentration and motility were higher for control and THC + Maca groups than in group THC and Maca. Conclusion: In vivo maca administration reduced the deleterious effect of THC on testicular parenchyma and semen production.

The Effect of Ferula communis Extract in Escherichia coli Lipopolysaccharide-Induced Neuroinflammation in Cultured Neurons and Oligodendrocytes

In recent decades, interest in natural compounds has increased exponentially due to their numerous beneficial properties in the treatment of various acute and chronic diseases. A group of plant derivatives with great scientific interest is terpenic compounds. Among the plants richest in terpenes, the genus Ferula L. is one of the most representative, and ferutinin, the most common sesquiterpene, is extracted from the leaves, rhizome, and roots of this plant. As reported in the scientific literature, ferutinin possesses antioxidant and anti-inflammatory properties, as well as valuable estrogenic properties. Neurodegenerative and demyelinating diseases are devastating conditions for which a definite cure has not yet been established. The mechanisms involved in these diseases are still poorly understood, and oxidative stress is considered to be both a key modulator and a common denominator. In the proposed experimental system, co-cultured human neurons (SH-SY5Y) and human oligodendrocytes (MO3.13) were treated with the pro-inflammatory agent lipopolysaccharide at a concentration of 1 μg/mL for 24 h or pretreated with ferutinin (33 nM) for 24 h and subsequently exposed to lipopolysaccharide 1 μg/mL for 24 h. Further studies would, however, be needed to establish whether this natural compound can be used as a support strategy in pathologies characterized by progressive inflammation and oxidative stress phenomena.

Role of Antioxidants in Cooled Liquid Storage of Mammal Spermatozoa

Cooled preservation of semen is usually associated with artificial insemination and genetic improvement programs in livestock species. Several studies have reported an increase in reactive oxidative species and a decrease in antioxidant substances and sperm quality parameters during long-term semen storage at refrigerated temperatures. The supplementation of antioxidants in extenders before refrigeration could reduce this detrimental effect. Various antioxidants have been tested, both enzymatic, such as superoxide dismutase and catalase, and non-enzymatic, such as reduced glutathione, vitamins E and C and melatonin. However, the problem of oxidative stress in semen storage has not been fully resolved. The effects of antioxidants for semen-cooled storage have not been reviewed in depth. Therefore, the objective of the present study was to review the efficiency of the supplementation of antioxidants in the extender during cooled storage of semen in livestock species.

Comparative proteomic analysis of seminal plasma proteins in relation to freezability of Dezhou donkey semen

Variation in donkey sperm freezability (capacity to withstand freeze-thawing) between ejaculates is a limitation for sperm cryopreservation. Seminal plasma proteins are essential for sperm function and also related to individual differences in sperm freezability. A Tandem Mass Tag (TMT) peptide labeling combine with a LC-MS/MS approach was conducted to quantitatively identify the seminal plasma proteins differentially abundant in ejaculates with optimal freezability characteristics (GFE) compared with those with suboptimal freezability characteristics (PFE). A total of 866 proteins were identified, and 99 ejaculates were in larger abundance in GFE samples. Differentially abundant proteins (DAPs) were subjected to intensive bioinformatic analysis. The majority of DAPs were involved in metabolic processes, oxidation-reduction processes and biological regulation. Results from functional protein analysis suggested that proteins functioned in oxidoreductase activity and acid phosphatase activity. This is the first report where there were analyses of the proteome of seminal plasma from donkey ejaculates with different freezability and to identify candidate proteins that could be used to explore the molecular mechanism related to donkey sperm cryotolerance. In this study, there also was elucidation of biomarkers for the early identification and selection of donkeys with optimal semen freezability.

The inhibition of spermatic cystine/glutamate antiporter xCT (SLC7A11) influences the ability of cryopreserved stallion sperm to bind to heterologous zonae pellucidae

Sperm are redox-regulated cells, and deregulation of their redox status is considered to affect male fertility and to reduce their fertilizing ability following biotechnological procedures, such as cryopreservation. Cystine (CysS), after incorporation in sperm via SLC7A11 antiporter, has been demonstrated to increase intracellular GSH content, the most important non enzymatic antioxidant. This study was aimed at investigating the role of SLC7A11 antiporter on frozen-thawed stallion sperm ability to respond to in vitro capacitating environment after post-thaw incubation with CysS and/or Sulfasalazine (SS), a specific inhibitor of SLC7A11 antiporter. Viability, motility, immunolocalization of tyrosine phosphorylated proteins and the ability to bind to heterologous zonae pellucidae were evaluated. Thawed sperm from seven stallions (2 ejaculates/stallion) was washed and resuspended in Tyrodes media; each thawed ejaculate was divided in Control (CTR) and 3 samples supplemented with: 0.5 mM Cystine (CysS), 500 μM Sulfasalazine (SS) and 0.5 mM CysS + 500 μM SS (CysS + SS). After 1 h of incubation at 37 °C, samples were washed twice, resuspended in capacitating BWW medium and incubated at 38 °C under 5% CO₂. After 30 and 60 min, sperm motility, viability and tyrosine phosphorylated protein immunolocalization, used as capacitation status index, were evaluated. After 30 min of capacitation, 4 × 10⁵ sperm were co-incubated with denuded pig oocytes in capacitation medium for 30 min for the heterologous binding assay. None of the sperm parameters studied (motility, viability and tyrosine phosphorylation) showed any difference respective to control. The number of sperm bound per oocyte (mean ± SEM) tended to increase in CysS group (44.0 ± 12.3) respect CTR (40.8 ± 10.8) while decreased in SS group (32.4 ± 7.8) (p < 0.01). Moreover, CysS + SS group showed a lower binding rate (32.0 ± 10.0) compared to CysS (p < 0.001). Our results suggest that CysS supplementation of thawed stallion sperm can influence their ability to bind to heterologous zona pellucidae as the inhibition of CysS incorporation by SLC7A11 reduced the number of sperm bound per oocyte. This effect does not seem to be ascribed to a modification of sperm motility, membrane integrity and tyrosine phosphorylation.

Antioxidants in assisted reproductive technologies: An overview on dog, cat, and horse

Assisted reproductive technologies (ARTs) are widely used as a tool to improve reproductive performance in both humans and animals. In particular, in the veterinary field, ARTs are used to improve animal genetics, recover endangered animals, and produce offspring in the event of subfertility or infertility in males or females. However, the use of ARTs did not improve the fertilization rate in some animals due to various factors such as the difficulty in reproducing an anatomical and humoral substrate typical of the natural condition or due to the increase in catabolites and their difficult elimination. The in vitro environment allows the production and increase in the concentration of substances, including reactive oxygen species (ROS), which could be harmful to gametes. If produced in high concentration, the ROS becomes deleterious, both in vitro and in vivo systems. It has been seen that the use of antioxidants can help neutralize or counteract the production of ROS. The present study aims to report the latest findings regarding the use of antioxidants in ARTs of some domestic species, such as dogs, cats, and horses, compared to other animal species, such as cattle, in which ARTs have instead developed more widely.

DNA fragmentation and morphometric studies in sperm of stallions supplemented with maca (Lepidium meyenii)

The reproductive performances of livestock play an essential role in the economic management of the farm. The improvement of semen quantity and quality through the use of food supplements that lack substances which are forbidden in animal feeding, or that may have detrimental effects, is an important goal. Maca (Lepidium meyenii) is a plant that has been used for centuries in the Andes for nutrition and fertility enhancement in humans and animals. The aim of this study was to evaluate the effects of food supplementation of stallions with maca during the breeding season on spermatozoa parameters such as DNA fragmentation and shape, which are two predictive indexes of spermatozoa functionality. For this purpose, ejaculate volume, semen gel-free volume, sperm concentration and motility, total sperm count, sperm DNA fragmentation and sperm head parameters (length, width, perimeter, area, shape factor, roughness) were measured in four stallions. Maca food supplementation in stallions during breeding reduced the percentage of spermatozoa with fragmented DNA, increased significantly sperm concentration and exerted an elongation of the spermatozoa head, a condition that is believed to improve spermatozoa functionality, suggesting that food supplementation of maca could be useful in horse breeding during the breeding season.

Strategies to expand the therapeutic potential of superoxide dismutase by exploiting delivery approaches

The overproduction of free radicals can cause oxidative-stress damage to a range of biomolecules, and thus potentially contribute to several pathologies, from neurodegenerative disorders to cardiovascular diseases and metabolic disorders. Endogenous antioxidant enzymes, such as superoxide dismutase (SOD), play an important role in diminishing oxidative stress. SOD supplementation could therefore be an effective preventive strategy to reduce the risk of free-radical overproduction. However, the efficacy of SOD administration is hampered by its rapid clearance. Several different approaches to improve the bioavailability of SOD have been explored in recent decades. This review intends to describe the rationale that underlie the various approaches and chemical strategies that have led to the most recent advances in SOD delivery. This critical description includes SOD conjugates, SOD loaded into particulate carriers (micelles, liposomes, nanoparticles, microparticles) and the most promising and suitable formulations for oral delivery, with a particular emphasis on reports of preclinical/clinical results. Likely future directions are also considered and reported.

Nicotinic Acid (Niacin) Supplementation in Cooling and Freezing Extenders Enhances Stallion Semen Characteristics

In the present study, we aimed to evaluate the possible protective effects of the nicotinic acid (NA) at three concentrations (10, 20, and 40 mM) on the equine cooled and frozen-thawed spermatozoa quality markers including viability, plasma membrane or acrosome integrity, DNA fragmentation, lipid peroxidation, and total oxidant levels. We also evaluated the effects of NA on preservation of the post-thaw sperm quality after 6 hours of cold storage before freezing. Five stallions were used for semen collections. The current experiment was repeated six times using pooled semen samples from two stallions, each time. We showed that NA at 20 and 40 mM concentrations could significantly improve the stallion sperm quality markers during cold storage. However, the protective effects were not different between 20 mM and 40 mM concentrations in most measures. Nicotinic acid could also improve the post-thaw stallion sperm quality at 10, 20, and 40 mM concentrations. However, the 40 mM concentration showed a negative impact on some post-thaw kinematic sperm parameters. Nicotinic acid at 10 and 20 mM concentrations could preserve the sperm cryo-tolerance to be frozen up to 8 hours after collection without a significant decline in most of the post-thaw sperm quality measures. Nicotinic acid could also decrease the level of the lipid peroxidation and total reactive oxygen/nitrogen species in the cooled and frozen-thawed spermatozoa, in a dose-dependent manner. Therefore, NA at 20 mM concentration could preserve most of the stallion sperm quality measures during cold storage (42 hours, 5°C) and enabled storage of cooled stallion semen for 6 hours before freezing without significant deterioration of the post-thaw sperm quality.

GPx6 is involved in the in vitro induced capacitation and acrosome reaction in porcine sperm

Glutathione peroxidases (GPxs) are regarded as important protectors against oxidative stress. Some members of this protein family were reported to play key roles in protecting sperm against oxidative stress. Whether GPx6 a member of the GPx family also plays a role in protection against oxidative stress is not known to date. The objective of the present study was to evaluate the localization and function of glutathione peroxidase 6 (GPx6) in boar accessory sex glands, seminal plasma, and sperm, as well as the effect of GPx6 on vitality and capacitation in boar sperm. qPCR and Western blot analysis demonstrated the presence of GPx6 in testis, epididymis, bulbourethral glands, prostate, seminal vesicle, sperm and seminal plasma. Incubation of sperm with an GPx6 antibody had no significant effect on the viability of boar sperm prior to capacitation. Surprisingly, when capacitated sperm was incubated with the GPx6 antibody for 240 min, sperm vitality was significantly improved. Western blotting showed that in capacitated sperm without prior pretreatment, GPx6 protein content was reduced compared to sperm before capacitation. To further confirm a role for GPx6 in sperm capacitation, we tested sperm acrosome reaction by ACR.2 and FITC-PSA. The results showed that treatment of sperm with the GPx6 antibody significantly increased sperm capacitation and acrosome reaction. Furthermore, we examined the concentration of cAMP in sperm after capacitation. ELISA demonstrated that the cAMP concentration in the sperm exposed to the GPx6 antibody was significantly higher than that of the control group. In addition, the exposure of sperm to the GPx6 antibody significantly increased the concentration of H₂O₂, while the expression of SOD3 and CAT were decreased. Based on these observations we would like to postulate that in the boar reproductive tract the GPx6 protein becomes attached to the sperm head preventing the sperm to undergo premature capacitation by affecting components of the antioxidant pathway. How GPx6 expression following ejaculation becomes suppressed to allow sperm capacitation to take place needs further investigation.