Effect of superoxide dismutase, catalase, and glutathione peroxidase supplementation in the extender on chilled semen of fertile and hypofertile dogs

Molecular Biomarkers of Canine Reproductive Functions

The aim of the current study is to review potential molecular biomarker substances selected so far as useful for assessing the quality of dog semen. Proteins, lipids, carbohydrates, and ions can serve as molecular biomarkers of reproductive functions (BRFs) for evaluating male reproductive health and identifying potential risk factors for infertility or reproductive disorders. Evaluation of BRF levels in semen samples or reproductive tissues may provide insights into the underlying causes of infertility, such as impaired sperm function, abnormal sperm-egg interaction, or dysfunction of the male reproductive tract. Molecular biomarker proteins may be divided into two groups: proteins that are well-studied, such as A-kinase anchoring proteins (AKAPs), albumins (ALBs), alkaline phosphatase (ALPL), clusterin (CLU), canine prostate-specific esterase (CPSE), cysteine-rich secretory protein 2 (CRISP2), lactotransferrin (LTF), metalloproteinases (MMPs), and osteopontin (OPN) and proteins that are not well-studied. Non-protein markers include lipid-based substances (fatty acids, phosphatidylcholine), carbohydrates (glycosaminoglycans), and ions (zinc, calcium). Assessing the levels of BRFs in semen samples may provide valuable information for breeding management and reproductive assessments in dogs. This review systematizes current knowledge that could serve as a starting point for developing practical tests with the use of biomarkers of canine reproductive functions and their predictive value for assisted reproductive technique outcomes and semen preservation.

G Protein-Coupled Estrogen Receptor (GPER) and ERs Are Modulated in the Testis-Epididymal Complex in the Normal and Cryptorchid Dog

There is growing evidence by the literature that the unbalance between androgens and estrogens is a relevant condition associated with a common canine reproductive disorder known as cryptorchidism. The role of estrogens in regulating testicular cell function and reproductive events is supposedly due to the wide expression of two nuclear estrogen receptors (ERs), ER-alpha and ER-beta and a trans-membrane G protein-coupled estrogen receptor (GPER) in the testis. In this study, immunohistochemistry, Western blotting and qRT-PCR were used to assess the distribution and expression of GPER in the testis-epididymal complex in the normal and cryptorchid dog. ER-alpha and ER-beta were also evaluated to better characterize the relative abundances of all three receptors. In addition, in these tissues, the expression level of two proteins as SOD1 and Nrf2 normally associated with oxidative stress was investigated to evaluate a possible relationship with ERs. Our data revealed changes in the distribution and expression of the GPER between the normal and cryptorchid dog. In particular, dogs affected by cryptorchidism showed an upregulation of GPER at level of the examined reproductive tract. Also considering the obtained result of a modulation of SOD1 and Nrf2 expression, we could hypothesize the involvement of GPER in the cryptorchid condition. Further studies are, however, necessary to characterize the role of GPER and its specific signaling mechanisms.

Effect of crocin supplementation in the extender on the quality of chilled canine semen

The aim of the study was to evaluate the effects of crocin on canine sperm quality parameters during prolonged storage at 4 °C. Ejaculates from 10 dogs were diluted in a TRIS- egg yolk extender supplemented with 0 (control group), 0.5, 1, and 2 mM crocin and stored at 4 °C. Sperm membrane functional integrity, motility, and kinetics were assessed after 3 h, 24 h, 4 days and 7 days of storage. Based on the results, the more efficient concentration of crocin (0.5 mM) was chosen to evaluate sperm intracellular ROS levels, lipid peroxidation, and DNA fragmentation vs. the control. Semen with the addition of 0.5 mM crocin with respect to the control exhibited: i) increased (P < 0.05) sperm membrane functionality at 4 and 7 days of storage; ii) higher (P < 0.05) average path (VAP), straight-line velocities (VSL), and beat cross frequency (BCF) at 4 d of storage at 4 °C; iii) decreased (P < 0.05) intracellular ROS levels after 3 and 24 h storage. No differences in lipid peroxidation and DNA fragmentation were recorded between the control and C0.5 groups at any time point. Lipid peroxidation did not increase over time, while DNA fragmentation increased (P < 0.05) in both groups after 4 days of storage. The results demonstrated that the enrichment of extender with crocin improves to a certain extent canine semen quality, particularly after 4 days of storage at 4 °C.

Extender Supplementation with Glutathione (GSH) and Taurine Improves In Vitro Sperm Quality and Antioxidant Status of New Zealand Rabbits during Chilled Storage for up to 72 hours

This study assessed the influence of supplementing the rabbit semen extender with various concentrations of glutathione (GSH) and taurine at 24, 48, and 72 h postchilling at 5°C. Semen samples were collected from 20 New Zealand bucks, and ejaculates with standard color, motility (>85%), about 0.5 mL volume, and ∼400 × 106/mL concentration were used and diluted with extenders supplemented with 0.5, 1, and 2 mM of GSH and 1, 5, and 10 mM of taurine and chilled at 5°C. Nonsupplemented samples were used as a control. Sperm's progressive motility, acrosome reaction, and extracellular oxidative stress biomarkers such as MDA contents and GPx, SOD, and CAT concentrations and intracellular transcriptomic levels of SOD and CAT genes were assessed. GSH and taurine supplementation improved the sperm's kinetics by reducing cooling-associated stress, which was ascertained by lowering MDA concentration and increasing SOD, CAT, and GPx concentrations (P < 0.05). Increasing the levels of antioxidant enzymes in the extender was due to the increasing mRNA copies of the SOD and CAT genes (P < 0.05). Furthermore, GSH and taurine maintained the fructose levels in the extender and lowered the GPT levels, which implies sperm membrane stability is maintained through GSH and taurine supplementation. GSH and taurine supplementation to the extender had protective influences on the in vitro rabbit semen quality during chilled storage for up to 72 h, which were remarkable with increasing supplementation dose and cooling time at 5°C.

Role of antioxidants in fertility preservation of sperm - A narrative review

Male fertility is affected by multiple endogenous stressors, including reactive oxygen species (ROS), which greatly deteriorate the fertility. However, physiological levels of ROS are required by sperm for the proper accomplishment of different cellular functions including proliferation, maturation, capacitation, acrosomal reaction, and fertilization. Excessive ROS production creates an imbalance between ROS production and neutralization resulting in oxidative stress (OS). OS causes male infertility by impairing sperm functions including reduced motility, deoxyribonucleic acid damage, morphological defects, and enhanced apoptosis. Several in-vivo and in-vitro studies have reported improvement in quality-related parameters of sperm following the use of different natural and synthetic antioxidants. In this review, we focus on the causes of OS, ROS production sources, mechanisms responsible for sperm damage, and the role of antioxidants in preserving sperm fertility.

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.

Effect of Aqueous Extract of Maca Addition to an Extender for Chilled Canine Semen

Simple Summary

The wide use of artificial insemination in dogs justifies the development of new strategies to prevent the reduction of fertilizing ability of stored semen. In recent years, the use of plant antioxidant supplementation has become increasingly popular. Maca (Lepidium meyenii) is an Andean edible root with antioxidant properties. The effectiveness of the oral supplementation of Maca in improving fresh semen quality and quantity and cooling or freezing ability has already been reported. This is the first in vitro study on the effects of aqueous extract of Maca on canine spermatozoa. The addition of low concentrations of aqueous extract of Maca to the canine chilled extender had positive effects only until 24 h of storage, increasing hyperactivation of sperm cells and preserving DNA integrity of spermatozoa in short-term storage. Meanwhile, a high concentration of Maca had an immediately deleterious effect on semen quality.

Abstract

Antioxidant supplementation has been proposed as a new strategy to improve the long-term preservation of semen. The aim of this study was to evaluate the effect of Maca supplementation of semen extender on quality-related canine semen parameters during cooling. Ejaculates from nine dogs were cooled for 7 days in the absence (control group) or in the presence of 10, 20 and 50 μL/mL of an aqueous extract of Maca. Sperm were evaluated for sperm viability, motility, DNA fragmentation and lipid peroxidation after 3 h, 24 h, 4 days and 7 days of storage. The addition of 10 μL/mL of Maca preserved sperm DNA and plasma membrane integrity at 3 h and increased sperm curvilinear velocity after 24 h. Treatment with 20 and 50 μL/mL of Maca increased the percentage of hyperactivated sperm after 3 h. Moreover, semen treated with 20 μL/mL of Maca decreased lipid peroxidation at 24 h. A significant reduction of sperm DNA and plasma membrane integrity as well as of kinetics parameters between 3 and 24 h of refrigerated storage with the higher concentration tested was observed. Although Maca was not able to protect canine semen with extended refrigeration storage time, it increased hyperactivation and preserved DNA integrity in short-term storage.

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.

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.

Glutathione supplementation in semen extender improves rabbit sperm attributes during refrigeration

In the present study, we evaluated the sustaining effect of various glutathione (GSH) concentrations in extender on rabbit sperm attributes during storage at 5°C for 24 h. Semen was collected from regular donor rabbit bucks using an artificial vagina and initially evaluated for sperm quality. The qualifying ejaculates were diluted with one of the extenders having 0, 1, 2, 4 or 8 mM GSH, to achieve a final concentration of 1×108 sperm/mL. The extended samples were stored at 5°C for 24 h. Sperm motility, motion kinetics, acrosome integrity and viability were assessed after 3, 6, 12 and 24 h of storage. The results showed that total sperm motility and sperm motion kinetics (oscillation index of the sperm, straightness index and beat cross frequency) were influenced (<em>P</em>&lt;0.05) by glutathione dose and refrigeration time. An interaction of (<em>P</em>&lt;0.05) GSH concentrations and refrigeration time was observed for sperm viability and acrosome reaction rate. In conclusion, the 4 mM GSH supplemented extender’s protective influence was remarkable to maintainrabbit sperm quality for 24 h 5°C.

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.

Triple-Negative Breast Cancer Comparison With Canine Mammary Tumors From Light Microscopy to Molecular Pathology

Many similar characteristics in human and dog cancers including, spontaneous development, clinical presentation, tumor heterogeneity, disease progression, and response to standard therapies have promoted the approval of this comparative model as an alternative to mice. Breast cancer represents the second most frequent neoplasm in humans after lung cancer. Triple-negative breast cancers (TNBC) constitute around 15% of all cases of breast cancer and do not express estrogen receptor (ER), progesterone receptor (PR), and do not overexpress human epidermal growth factor receptor 2 (HER2). As a result, they do not benefit from hormonal or trastuzumab-based therapy. Patients with TNBC have worse overall survival than patients with non-TNBC. Lehmann and collaborators described six different molecular subtypes of TNBC which further demonstrated its transcriptional heterogeneity. This six TNBC subtype classification has therapeutic implications. Breast cancer is the second most frequent neoplasm in sexually intact female dogs after skin cancer. Canine mammary tumors are a naturally occurring heterogeneous group of cancers that have several features in common with human breast cancer (HBC). These similarities include etiology, signaling pathway activation, and histological classification. Molecularly CMTs are more like TNBCs, and therefore dogs are powerful spontaneous models of cancer to test new therapeutic approaches, particularly for human TNBCs. More malignant tumors of the breast are more often ER and PR negative in both humans and dogs. Promising breast cancer biomarkers in both humans and canines are cancer-associated stroma (CAS), circulating tumor cells and tumor DNA (ctDNA), exosomes and miRNAs, and metabolites.

An Unusual Case of Testicular Disorder in Sex Development of Arabian Mare (64,XX SRY-Negative)

Simple Summary

An interesting case of a horse with an XX, SRY-negative disorder of sexual development (DSD) is reported in this paper. In particular, the animal showed the development of both male and female portions of reproductive organs. The possible genetic background of this abnormality is also discussed.

Abstract

A 3-year-old Arabian mare underwent medical examinations due to the presence of abnormalities of the reproductive apparatus and stallion behavior (nervous temperament, aggressiveness, masculine attitude). During the clinical visit, an anovulvar distance shorter than normal was observed; moreover, vulvar lips were dorsally fused except for the lower neckline, showing a blind ending from which a penis-like structure protruded. The ultrasound examination revealed the presence of a cervix and corpus of a uterus, hypoplastic uterine horns, and small gonads with an echogenicity similar to a testis. Blood testosterone levels ranged from 0.4 to 0.6 ng/mL. Cytogenetic analysis showed a normal female karyotype (2n = 64,XX), while PCR amplification of SRY and ZFY genes revealed the absence of a Y chromosome. At necroscopic examination, internal genitalia arising from the genital ridge in the form of masculine type structures were found, while those deriving from the Mullerian ducts were of feminine type. In addition, an infundibular portion of the salpinx at the cranial pole of the gonads was found. This is the first case in equine species of DSD 2n = 64,XX SRY-negative, with the simultaneous presence of male (hypoplastic testicles, epididymal portions, and a penis-like structure) and female (cervix, horn and body of a hypoplastic uterus) genital structures.

Does Tribulus terrestris improve toxic effect of Malathion on male reproductive parameters?

Background:

Tribulus terrestris has antioxidant and free-radical-scavenging properties. Malathion is the most common organophosphate, which is capable to produce free radicals and induce disturbance on some of male reproductive parameters. This study was designed to evaluate the effects of T. terrestris extract against damage induced by Malathion to the reproductive parameter of male rats.

Materials and Methods:

In this experimental study, 48 male Wistar rats were randomly assigned to eight groups: first group, sham group (normal saline); second group, Malathion (250 mg/kg) group; third to fifth groups, T. terrestris groups (2.5, 5, and 10 mg/kg body weight, respectively); and sixth to eight groups, Malathion + T. terrestris groups (2.5, 5, and 10 mg/kg). Tribulus terrestris extract (2.5, 5, and 10 mg/kg body weight, respectively) administrated orally, and daily for 8 weeks. The sperm parameters, testis malondialdehyde (MDA), serum total antioxidant capacity, serum testosterone level, and the height of germinal layer were evaluated and analyzed statistically.

Results:

All the values of male reproductive parameters reduced significantly in the Malathion group as compared to the sham group (P < 0.01) except MDA level, which increased significantly. The T. terrestris and T. terrestris + Malathion treatments in all doses increased the whole parameters significantly as compared to the Malathion group (P < 0.01) except MDA level, which decreased significantly. No significant changes were observed in all T. terrestris groups as compared to the sham group (P > 0.05).

Conclusion:

Tribulus terrestris extract administration attenuates the toxic effects of Malathion on some of the male reproductive parameters.

CRIF1 overexpression facilitates tumor growth and metastasis through inducing ROS/NFκB pathway in hepatocellular carcinoma

CR6-interacting factor 1 (Crif1) is a mitochondrial protein which is required for the assembly of oxidative phosphorylation (OXPHOS) complexes. Our bioinformatics analysis based on Cancer Genome Atlas (TCGA) database revealed an aberrant overexpression of CRIF1 in hepatocellular carcinoma (HCC). However, the clinical significance and biological functions of CRIF1 are still unclear in this malignancy. Here, we report that CRIF1 is frequently overexpressed in HCC cells mainly due to the downregulation of miR-497-5p, which is associated with poor prognosis of patients with HCC. CRIF1-promoted HCC growth and metastasis by suppressing cell apoptosis and inducing cell cycle progression and epithelial to mesenchymal transition (EMT). Mechanistically, increased mitochondrial ROS production and consequently activation of the NFκB signaling pathway was found to be involved in the promotion of growth and metastasis by CRIF1 in HCC cells. In summary, CRIF1 plays an oncogenic role in HCC progression through activating ROS/NFKB pathway, implying CRIF1 as a potential prognostic factor and therapeutic target in HCC.

Canine spermatozoa-What do we know about their morphology and physiology? An overview

Spermatozoa are unique cells because of their morphological and physiological characteristics. They are produced during the process called spermatogenesis. Spermatogenesis consists of three phases: spermatocytogenesis, spermiogenesis and spermiation, during which spermatozoa undergo several changes. Spermatogenesis takes place within the seminiferous tubules containing two types of cells-the germ cells and the Sertoli cells-that alongside the Leydig cells, which play an important role when it comes to normal fertility. Everything is regulated by the hypothalamic-pituitary-gonadal axis and specific hormones due to multi-hormonal feedback systems. Spermatozoa possess morphological and physiological features, which are sometimes completely different from what is observed in various somatic cells. What is more, canine spermatozoa have specific characteristics making them special compared to the spermatozoa of other mammalian species. The metabolic energy production, which is crucial for the appropriate functioning of spermatozoa, can be fuelled by different metabolic pathways utilizing different chemical substrates. Inseparable from the oxidative phosphorylation process is the production of reactive oxygen species, which are both essential and toxic to spermatozoa. Furthermore, epididymis is a very important structure, responsible for the transport and maturation of spermatozoa, which are then stored in the last segment of epididymis-the epididymal cauda. Moreover, the retrieval of spermatozoa from the epididymides is crucial for the development of assisted reproduction techniques and sperm cryopreservation methods. The information gained from the research on domestic dogs might be transferred to their wild relatives, especially those species categorized as endangered.

Lepidium meyenii (Maca) in male reproduction

Lepidium meyenii (Maca) is an edible root plant that grows in the Andean region of Peru. For centuries, the plant has been used as a dietary supplement for its nutritional and therapeutic properties. Maca are rich in high value nutritional elements and secondary metabolites (macaridine, macamides and glucosinolates) with high biological activity. Several studies demonstrated various biological effects of Maca mainly in the field of fertility. The aim of this review is to summarize the state of knowledge on the properties of Maca on male reproduction. Literature data was performed in PubMed with researches published from 2000 to 2019. The research showed results related to the effects of Maca on the quality and quantity of the semen, sexual behaviour and disorders of the male genital tract. Despite the numerous studies carried out on different animal species, further research is needed to clarify the mechanisms of action of Maca.

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

During cold storage stallion spermatozoa experience undergo oxidative stress, which can impair sperm function and fertilizing capacity. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) are the main endogenous enzymatic antioxidants in stallion seminal plasma, and counteract reactive oxygen species. Semen dilution reduces the endogenous antioxidant concentrations. The aim of this study was to investigate whether addition of 15 IU/mL each of SOD, CAT, and GPX to diluted stallion semen would ameliorate a reactive oxygen-mediated decrease in semen quality during 72 h of storage at 5 °C. Ejaculates (n = 7) were divided in two aliquots and diluted in INRA 96 without (control) or with addition of antioxidants. Semen analysis was performed at the time of dilution and every 24 h during chilled storage. Antioxidant supplementation completely inhibited the storage-dependent increase in activated caspase 3 (P < 0.05). Concomitantly, the antioxidant-supplemented samples had a greater percentage of viable, motile and rapidly moving sperm than control samples after 72 h storage (P < 0.05). The DNA damage, as evaluated by TUNEL assay and SCSA, increased with storage time (P < 0.05). Antioxidant supplementation did not prevent, but did significantly reduce the increase in DNA strand breakage. The results indicate part of the intrinsic apoptotic pathway leading to effector caspase activation was inhibited, although an activation of molecules with endonuclease activity still occurred. In conclusion, adding equal concentrations of SOD, CAT and GPX to a semen extender suppressed caspase-3 activation and improved preservation of stallion sperm motility and viability during 72 h of storage at 5 °C.

Chemical Analysis of Lepidium meyenii (Maca) and Its Effects on Redox Status and on Reproductive Biology in Stallions †

The present study was conducted to assess the chemical composition of Yellow Maca (Lepidium meyenii) and its biological activity on stallions following oral administration of hypocotyl powder. Maca was subjected to methanolic extraction and the chemical analysis was carried out by LC-MS-QTOF (liquid chromatography-mass spectrometry). Our results showed that Maca contains some effective antioxidants, a high percentage of glucosinolates, and other important components with a high antioxidant capacity. To evaluate the plant biological activity in stallions fed with Maca powder for 60 days, the redox status and some reproductive parameters were investigated. Blood and semen samples were collected at 0, 30, 60, and 90 days from the beginning of this study. Blood samples showed a decrease of the reactive oxygen metabolites, evaluated by d-ROMs test, and an increase of the antioxidant barrier in terms of biological antioxidant potential (BAP test), powerful oxidant capacity (OXY-Adsorbent test), and thiols evaluation (-SHp test). Furthermore, semen samples showed a positive trend during Maca administration in the following parameters: ejaculate volumes and sperm concentrations, total and progressive motility, and acrosome integrity.