Basal energetic metabolism in sperm, particularly oxidative phosphorylation, is known to condition not only their oocyte fertilising ability, but also the subsequent embryo development. While the ...molecular pathways underlying these events still need to be elucidated, reactive oxygen species (ROS) could have a relevant role. We, therefore, aimed to describe the mechanisms through which mitochondrial activity can influence the first stages of embryo development.
We first show that embryo development is tightly influenced by both intracellular ROS and mitochondrial activity. In addition, we depict that the inhibition of mitochondrial activity dramatically decreases intracellular ROS levels. Finally, we also demonstrate that the inhibition of mitochondrial respiration positively influences sperm DNA integrity, most likely because of the depletion of intracellular ROS formation.
Collectively, the data presented in this work reveals that impairment of early embryo development may result from the accumulation of sperm DNA damage caused by mitochondrial-derived ROS.
Male idiopathic infertility accounts for 15–25% of reproductive failure. One of the factors that has been linked to this condition is oxidative stress (OS), defined as the imbalance between ...antioxidants and reactive oxygen species. Amongst the different factors that protect the cell against OS, the members of the glutathione S-transferase (GST) superfamily play an important role. Interestingly, reduction or lack of some GSTs has been associated to infertility in men. Therefore, and to clarify the relationship between GSTs and male fertility, the aim of this work is to describe the role that GSTs play in the male reproductive tract and in sperm physiology. To that end, the present review provides a novel perspective on the triple role of GSTs (detoxification, regulation of cell signalling and fertilisation), and reports their localisation in sperm, seminal plasma and the male reproductive tract. Furthermore, we also tackle the existing correlation between some GST classes and male fertility. Due to the considerable impact of GSTs in human pathology and their tight relationship with fertility, future research should address the specific role of these proteins in male fertility, which could result in new approaches for the diagnosis and/or treatment of male infertility.
In pig production, the optimization of artificial insemination (AI) efficiency significantly relies on the accurate assessment of semen quality and fertility of boars. Traditional methods such as ...conventional seminogram techniques, although long-standing, exhibit limited sensitivity in predicting boar fertility, warranting the exploration of novel molecular markers. This review synthesizes the current knowledge on the utilization of molecular markers for semen quality evaluation and male fertility prediction in boars, providing an in-depth examination of molecular markers in this context. Specifically, the present work delves into the potential of OMICs technologies, encompassing genetic and genomic approaches, transcriptomics, proteomics, and metabolomics. A diverse array of molecular markers, including genomic regions associated with sperm quality and male fertility, chromatin integrity, mitochondrial DNA content, mRNA and non-coding RNA signatures, as well as proteins and metabolites in sperm and seminal plasma, are identified as promising molecular markers for fertility prediction in boars. Furthermore, the need of validating biomarkers and their practical implementation in AI centres is here emphasized. Addressing these considerations and integrating molecular markers within the swine breeding field holds the potential to enhance reproductive management practices and optimize productivity in boar breeding programs. This integration can significantly improve overall efficiency within the pig breeding industry.
•OMICs technologies offer novel markers for boar fertility prediction.•Validation and cost-effective tests are crucial for practical application.•Molecular markers can improve the efficiency of the pig breeding industry.
The objective of the present study was to determine the physiological role of voltage-gated hydrogen channels 1 (HVCN1 channels) during in vitro capacitation of pig spermatozoa. Sperm samples from 20 ...boars were incubated in capacitating medium for 300 minutes (min) in the presence of 2-guanidino benzimidazole (2-GBI), a specific HVCN1-channel blocker, added either at 0 min or after 240 min of incubation. Control samples were incubated in capacitating medium without the inhibitor. In all samples, acrosomal exocytosis was triggered with progesterone after 240 min of incubation. Sperm viability, sperm motility and kinematics, acrosomal exocytosis, membrane lipid disorder, intracellular calcium levels and mitochondrial membrane potential were evaluated after 0, 60, 120, 180, 240, 250, 270 and 300 min of incubation. While HVCN1-blockage resulted in altered sperm viability, sperm motility and kinematics and reduced mitochondrial membrane potential as compared to control samples, at any blocker concentration and incubation time, it had a non-significant effect on intracellular Ca
levels determined through Fluo3-staining. The effects on acrosomal exocytosis were only significant in blocked samples at 0 min, and were associated with increased membrane lipid disorder and Ca
levels of the sperm head determined through Rhod5-staining. In conclusion, HVCN1 channels play a crucial role in the modulation of sperm motility and kinematics, and in Ca
entrance to the sperm head.
Seminal plasma (SP), a fluid composed mainly by secretions from accessory sex glands, contains a heterogenous population of extracellular vesicles (EVs), involved in several reproductive ...physiological processes. Seminal plasma has been found to modulate ovary function, in terms of hormone secretion and immune regulation. This study evaluated the potential effect of SP-EV-subsets on the modulation of cumulus-oocyte-complex (COCs) physiology during in vitro maturation (IVM). Two SP-EV-subsets, small-EVs (S-EVs) and large-EVs (L-EVs), were isolated from pig SP by size-exclusion-chromatography. Next, COCs were IVM in the absence (control) or presence of each SP-EV-subset to evaluate their uptake by COCs (PKH67-EVs labelling) and their effect on oocyte and cumulus cells (CCs) (gene expression, and progesterone and estradiol-17β levels). S-EVs and L-EVs were able to bind CCs but not oocytes. Supplementation with L-EVs induced changes (P ≤ 0.05) in the transcript levels of oocyte maturation- (HAS2) and steroidogenesis-related genes (CYP11A1 and HSD3B1) in CCs. No effect on nuclear oocyte maturation and progesterone and estradiol-17β levels was observed when COCs were IVM with any of the two SP-EV-subsets. In conclusion, while SP-EV-subsets can be integrated by CCs during IVM, they do not affect oocyte maturation and only L-EVs are able to modulate CCs function, mainly modifying the expression of steroidogenesis-related genes.
Assisted reproductive technology (ART) is an essential tool to overcome infertility, and is a worldwide disease that affects millions of couples at reproductive age. Sperm selection is a crucial step ...in ART treatment, as it ensures the use of the highest quality sperm for fertilization, thus increasing the chances of a positive outcome. In recent years, advanced sperm selection strategies for ART have been developed with the aim of mimicking the physiological sperm selection that occurs in the female genital tract. This systematic review sought to evaluate whether advanced sperm selection techniques could improve ART outcomes and sperm quality/functionality parameters compared to traditional sperm selection methods (swim-up or density gradients) in infertile couples. According to preferred reporting items for systematic reviews and meta-analyses (PRISMA guidelines), the inclusion and exclusion criteria were defined in a PICOS (population, intervention, comparator, outcome, study) table. A systematic search of the available literature published in MEDLINE-PubMed until December 2021 was subsequently conducted. Although 4237 articles were recorded after an initial search, only 47 studies were finally included. Most reports (30/47; 63.8%) revealed an improvement in ART outcomes after conducting advanced vs. traditional sperm selection methods. Among those that also assessed sperm quality/functionality parameters (12/47), there was a consensus (10/12; 83.3%) about the beneficial effect of advanced sperm selection methods on these variables. In conclusion, the application of advanced sperm selection methods improves ART outcomes. In spite of this, as no differences in the reproductive efficiency between advanced methods has been reported, none can be pointed out as a gold standard to be conducted routinely. Further research addressing whether the efficiency of each method relies on the etiology of infertility is warranted.
Parkinson disease protein 7 (PARK7) is a multifunctional protein known to be involved in the regulation of sperm motility, mitochondrial function, and oxidative stress response in mammalian sperm. ...While ROS generation is needed to activate the downstream signaling pathways required for sperm to undergo capacitation, oxidative stress has detrimental effects for sperm cells and a precise balance between ROS levels and antioxidant activity is needed. Considering the putative antioxidant role of PARK7, the present work sought to determine whether this protein is related to the sperm ability to withstand in vitro capacitation. To this end, and using the pig as a model, semen samples were incubated in capacitation medium for 300 min; the acrosomal exocytosis was triggered by the addition of progesterone after 240 min of incubation. At each relevant time point (0, 120, 240, 250, and 300 min), sperm motility, acrosome and plasma membrane integrity, membrane lipid disorder, mitochondrial membrane potential, intracellular calcium and ROS were evaluated. In addition, localization and protein levels of PARK7 were also assessed through immunofluorescence and immunoblotting. Based on the relative content of PARK7, two groups of samples were set. As early as 120 min of incubation, sperm samples with larger PARK7 content showed higher percentages of viable and acrosome-intact sperm, lipid disorder and superoxide levels, and lower intracellular calcium levels when compared to sperm samples with lower PARK7. These data suggest that PARK7 could play a role in preventing sperm from undergoing premature capacitation, maintaining sperm viability and providing a better ability to keep ROS homeostasis, which is needed to elicit sperm capacitation. Further studies are required to elucidate the antioxidant properties of PARK7 during in vitro capacitation and acrosomal exocytosis of mammalian sperm, and the relationship between PARK7 and sperm motility.
The assessment of sperm DNA integrity has been proposed as a complementary test to conventional mammalian semen analysis. In this sense, single-strand (SSB) and double-strand (DSB) DNA breaks, the ...two types of sperm DNA fragmentation (SDF), have been reported to have different aetiologies and to be associated to different fertility outcomes in bovine and humans. Considering that no studies in porcine have addressed how SDF may affect sperm quality and fertility outcomes, the present work aimed to determine the impact of global DNA damage, SSB and DSB on sperm quality and in vitro fertilising ability. To this end, 24 ejaculates (one per boar) were split into three aliquots: the first was used to assess sperm quality parameters through a computer-assisted sperm analysis (CASA) system and flow cytometry; the second was used to perform in vitro fertilisation, and the third, to evaluate sperm DNA integrity using alkaline and neutral Comet assays.
The results showed that global DNA damage negatively correlates (P < 0.05) with normal sperm morphology (R = - 0.460) and progressive motility (R = - 0.419), and positively with the percentage of non-viable sperm (R = 0.507). Multiple regression analyses showed that non-viable sperm were related to SSB (β = - 0.754). In addition, while fertilisation did not seem to be affected by sperm DNA integrity, global DNA damage, DSB and SSB were found to be correlated to embryo development outcomes. Specifically, whereas global DNA damage and DSB negatively affected (P < 0.05) the later preimplantation embryo stages (percentage of early blastocyst/blastocyst D6: for global DNA damage, R = - 0.458, and for DSB, R = - 0.551; and percentage of hatching/hatched blastocyst D6: for global DNA damage, R = - 0.505, and for DSB, R = - 0.447), global DNA damage and SSB had a negative impact (P < 0.05) on the developmental competency of fertilised embryos (R = - 0.532 and R = - 0.515, respectively). Remarkably, multiple regression analyses supported the associations found in correlation analyses. Finally, the present work also found that the inclusion of Comet assays to the conventional sperm quality tests improves the prediction of blastocyst formation (AUC = 0.9021, P < 0.05), but not fertilisation rates (P > 0.05).
Considering all these findings, this work sets a useful model to study how SDF negatively influences fertility.
Nuts have formed part of human diets throughout the ages. In recent decades, research has shown they are key foods in dietary patterns associated with lower chronic disease risk. The current state of ...climate change, however, has introduced an imperative to review the impact of dietary patterns on the environment with a shift to plant-based diets. Nuts emerge as a significant source of protein in plant-based diets and are a minimally processed and sustainable food. Research in this area is evolving to drive better production methods in varying climate conditions. Nevertheless, nut consumption remains an important contributor to human health. The mechanisms of action can be explained in terms of the nutrients they deliver. Studies of nut consumption have linked components such as monounsaturated fatty acids, plant omega-3 fatty acids, antioxidants, and plant sterols to improved lipoprotein profiles, lower blood pressure, and reduced cardiovascular disease risk. Preliminary research also indicates possible beneficial effects of nut consumption on reproductive health. In any case, the ultimate effects of foods on health are the results of multiple interactive factors, so where nuts fit within dietary patterns is a significant consideration for research translation. This has implications for research methodologies, including categorization within food groups and inclusion in Healthy Dietary Indices. The aim of this narrative review is to outline new focal points for investigation that examine the environmental and some novel human health impacts of nut consumption and discuss future directions for research.
•Sperm fertility biomarkers are of interest in dairy cattle.•Glutathione S-transferase Mu 3 is not related to bovine sperm quality.•Glutathione S-transferase Mu 3 is associated to morphologically ...abnormal sperm.•Glutathione S-transferase Mu 3 in sperm is associated to in vivo fertility in cattle.•Glutathione S-transferase Mu 3 may be used as a fertility biomarker in cattle.
In the dairy breeding industry, pregnancy of dairy cows is essential to initiate milk production, so that high fertility rates are required to increase their productivity. In this regard, sperm proteins that are indicative of sperm quality and/or fertility have become an important target of study. Glutathione S-transferase Mu 3 (GSTM3) has been established as a fertility and sperm quality parameter in humans and pigs and, consequently, it might be a potential biomarker in cattle. For this reason, the present work aimed to determine if GSTM3 could predict sperm quality and in vivo fertility in this species. Sperm quality was assessed with flow cytometry and computer-assisted sperm analysis. Immunoblotting and immunofluorescence analysis were performed to determine the presence and localisation pattern of sperm GSTM3. This enzyme was found to be present in bovine sperm and to be localised along the sperm tail and the equatorial segment of the head. No significant associations between sperm GSTM3 and sperm quality parameters were observed, except a negative association with morphologically abnormal sperm having a coiled tail. In addition, and more relevant, higher levels of GSTM3 in sperm were seen in bulls showing lower in vivo fertility rates. In conclusion, our data evidenced the presence of GSTM3 in bovine sperm. Moreover, we suggest that, despite not being associated with sperm quality, GSTM3 might be an in vivo subfertility biomarker in cattle sperm, and that high levels of this protein could be an indicative of defective spermatogenesis and/or epididymal maturation.
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