Fertilizing Capacity Of Spermatozoa Research Articles

GPX5-Enriched Exosomes Improve Sperm Quality and Fertilization Ability

Semen preservation quality affects the artificial insemination success rate, and seminal exosomes are rich in various proteins that are transferable to sperm and conducive to sperm-function preservation during storage. However, the specific effects of these proteins remain unclear. In this study, the specific effects of these proteins on semen preservation quality and fertilization capacity were investigated through a proteomic analysis of seminal exosomes from boars with high conception rates (HCRs) and low conception rates (LCRs). The results revealed significant differences in the expression of 161 proteins between the two groups, with the GPX5 level being significantly higher in the HCR group (p < 0.05). The role of GPX5 was further investigated by constructing engineered exosomes enriched with GPX5 (Exo-GPX5), which could successfully transfer GPX5 to sperm. Compared to the control group, Exo-GPX5 could significantly improve sperm motility on storage days 4 and 5 and enhance the acrosome integrity on day 5 (p < 0.05). Additionally, Exo-GPX5 increased the total antioxidant capacity (T-AOC) of sperm, reduced the malondialdehyde (MDA) level, and decreased the expression of antioxidant proteins SOD1 and CAT (p < 0.05). In simulated fertilization experiments, Exo-GPX5-treated sperm exhibited higher capacitation ability and a significant increase in the acrosome reaction rate (p < 0.05). Overall, Exo-GPX5 can improve boar semen quality under 17 °C storage conditions and enhance sperm fertilization capacity.

Fertility after photodynamic inactivation of bacteria in extended boar semen.

Antimicrobial resistance is an increasing challenge in semen preservation of breeding animals, especially in the porcine species. Bacteria are a natural component of semen, and their growth should be inhibited to protect sperm fertilizing capacity and the female's health. In pig breeding, where semen is routinely stored at 17°C in the liquid state, alternatives to conventional antibiotics are urgently needed. Photodynamic inactivation (PDI) of bacteria is a well-established tool in medicine and the food industry but this technology has not been widely adopted in semen preservation. The specific challenge in this setting is to selectively inactivate bacteria while maintaining sperm integrity and functionality. The aim of this study was to test the principle of PDI in liquid stored boar semen using the photosensitizer 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) and a white light LED-setup. In the first step, photophysical experiments comprising singlet oxygen phosphorescence kinetics of TMPyP and determination of the photosensitizer triplet time revealed a sufficiently high production of reactive singlet oxygen in the Androstar Premium semen extender, whereas seminal plasma acted as strong quencher. In vitro experiments with extended boar semen showed that the established PDI protocol preserves sperm motility, membrane integrity, DNA integrity, and mitochondrial activity while efficiently reducing the bacteria below the detection limit. A proof-of-concept insemination study confirmed the in vivo fertility of semen after photodynamic treatment. In conclusion, using the PDI approach, an innovative tool was established that efficiently controls bacteria growth in extended boar and maintains sperm fertility. This could be a promising contribution to the One Health concept with the potential to reduce antimicrobial resistance in animal husbandry.

Flagellar pH homeostasis mediated by Na+/H+ exchangers regulates human sperm functions through coupling with CatSper and KSper activation.

Whether and how do Na+/H+ exchangers (NHEs) regulate the physiological functions of human sperm? NHE-mediated flagellar intracellular pH (pHi) homeostasis facilitates the activation of the pH-sensitive, sperm-specific Ca2+ channel (CatSper) and the sperm-specific K+ channel (KSper), which subsequently modulate sperm motility, hyperactivation, flagellar tyrosine phosphorylation, and the progesterone (P4)-induced acrosome reaction. Sperm pHi alkalization is an essential prerequisite for the acquisition of sperm-fertilizing capacity. Different sperm functions are strictly controlled by particular pHi regulatory mechanisms. NHEs are suggested to modulate sperm H+ efflux. This was a laboratory study that used samples from >50 sperm donors over a period of 1 year. To evaluate NHE action on human sperm function, 5-(N,N-dimethyl)-amiloride (DMA), a highly selective inhibitor of NHEs, was utilized. All experiments were repeated at least five times using different individual sperm samples or cells. By utilizing the pH fluorescent indicator pHrodo Red-AM, we detected alterations in single-cell pHi value in human sperm. The currents of CatSper and KSper in human sperm were recorded by the whole-cell patch-clamp technique. Changes in population and single-cell Ca2+ concentrations ([Ca2+]i) of human sperm loaded with Fluo 4-AM were measured. Membrane potential (Vm) and population pHi were quantitatively examined by a multimode plate reader after sperm were loaded with 3,3'-dipropylthiadicarbocyanine iodide and 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester, respectively. Sperm motility parameters were assessed by a computer-assisted semen analysis system. Tyrosine phosphorylation was determined by immunofluorescence, and sperm acrosome reaction was evaluated by Pisum sativum agglutinin-FITC staining. DMA-induced NHEs inhibition severely acidified the human sperm flagellar pHi from 7.20 ± 0.04 to 6.38 ± 0.12 (mean ± SEM), while the effect of DMA on acrosomal pHi was less obvious (from 5.90 ± 0.13 to 5.57 ± 0.12, mean ± SEM). The whole-cell patch-clamp recordings revealed that NHE inhibition remarkably suppressed alkalization-induced activation of CatSper and KSper. As a consequence, impairment of [Ca2+]i homeostasis and Vm maintenance were detected in the presence of DMA. During the capacitation process, pre-treatment with DMA for 2 h potently decreased sperm pHi, which in turn decreased sperm motility and kinetic parameters. Sperm capacitation-associated functions, including hyperactivation, tyrosine phosphorylation, and P4-induced acrosome reaction, were also compromised by NHE inhibition. N/A. This was an in vitro study. Caution should be taken when extrapolating these results to in vivo applications. This study revealed that NHEs are important physiological regulators for human CatSper and KSper, which are indispensable for human sperm fertility, suggesting that malfunction of NHEs could be an underlying mechanism for the pathogenesis of male infertility. This work was supported by the National Natural Science Foundation of China (32271167 and 81871202 to X.Z.), Jiangsu Innovation and Entrepreneurship Talent Plan (JSSCRC20211543 to X.Z.), the Social Development Project of Jiangsu Province (No. BE2022765 to X.Z.), the Society and livelihood Project of Nantong City (No. MS22022087 to X.Z.), and the Natural Science Foundation of Jiangsu Province (BK20220608 to H.K.). The authors have no competing interests to declare.

Differential protein repertoires related to sperm function identified in extracellular vesicles (EVs) in seminal plasma of distinct fertility buffalo (Bubalus bubalis) bulls.

Buffalo bulls are backbone of Indian dairy industry, and the quality of semen donating bulls determine the overall production efficiency of dairy farms. Seminal plasma harbor millions of lipid bilayer nanovesicles known as extracellular vesicles (EVs). These EVs carry a heterogenous cargo of essential biomolecules including fertility-associated proteins which contribute to fertilizing potential of spermatozoa. In this study, we explored size, concentration, and complete proteome profiles of SP EVs from two distinct fertility groups to uncover proteins influencing bull fertility. Through Dynamic Light Scattering (DLS) it was found that purified EVs were present in 7-14 size exclusion chromatographic (SEC) fractions with sizes ranging from 146.5 to 258.7nm in high fertile (HF) and low fertile (LF) bulls. Nanoparticle Tracking Analysis (NTA) confirmed the size of seminal EVs up to 200nm, and concentrations varying from 2.84 to 6.82 × 1011 and 3.57 to 7.74 × 1011 particles per ml in HF and LF bulls, respectively. No significant difference was observed in size and concentration of seminal EVs between two groups. We identified a total of 1,862 and 1,807 proteins in seminal EVs of HF and LF bulls, respectively using high throughput LC-MS/MS approach. Out of these total proteins, 1,754 proteins were common in both groups and about 87 proteins were highly abundant in HF group while 1,292 were less abundant as compared to LF bulls. Gene ontology (GO) analysis, revealed that highly abundant proteins in HF group were mainly part of the nucleus and involved in nucleosome assembly along with DNA binding. Additionally, highly abundant proteins in EVs of HF group were found to be involved in spermatogenesis, motility, acrosome reaction, capacitation, gamete fusion, and cryotolerance. Two highly abundant proteins, protein disulfide-isomerase A4 and gelsolin, are associated with sperm-oocyte fusion and acrosome reaction, respectively, and their immunolocalization on spermatozoa may indicate that these proteins are transferred through EVs. Our evidences support that proteins in EVs and subsequently their presence on sperm, are strongly associated with sperm functions. Altogether, our investigation indicates that SPEVs possess crucial protein repertoires that are essential for enhancing sperm fertilizing capacity.

Resveratrol Improves the Frozen-Thawed Ram Sperm Quality.

Cryopreservation generates a substantial quantity of ROS in semen, leading to a decline in sperm quality and fertilization capacity. The objective of this study was to investigate the effects of resveratrol and its optimal concentration on ram sperm quality after cryopreservation. Ram semen was diluted with a freezing medium containing different concentrations of resveratrol (0, 25, 50, 75, and 100 μM). After thawing, various sperm parameters such as total motility, progressive motility, acrosome integrity, plasma membrane integrity, mitochondrial membrane potential, glutathione (GSH) content, glutathione synthase (GPx) activity, superoxide dismutase (SOD) activity, catalase (CAT) activity, lipid peroxidation (LPO) content, malondialdehyde (MDA) content, ROS level, SIRT1 level, DNA oxidative damage, and AMPK phosphorylation level were assessed. In addition, post-thaw sperm apoptosis was evaluated. Comparatively, the addition of resveratrol up to 75 μM significantly improved the sperm motility and sperm parameters of cryopreserved ram sperm. Specifically, 50 μM resveratrol demonstrated a notable enhancement in acrosome and plasma membrane integrity, antioxidant capacity, mitochondrial membrane potential, adenosine triphosphate (ATP) content, SIRT1 level, and AMPK phosphorylation levels compared to the control group (p < 0.05). It also significantly (p < 0.05) reduced the oxidative damage to sperm DNA. However, detrimental effects of resveratrol were observed at a concentration of 100 μM resveratrol. In conclusion, the addition of 50 μM resveratrol to the cryopreservation solution is optimal for enhancing the quality of cryopreserved ram sperm.

The effect of different concentrations of N-acetyl cysteine on liquefaction, quality and fertility of chilled semen in dromedary camel

The objectives of the current study were to evaluate the effects of N-acetyl cysteine (NAC) on semen liquefaction and sperm quality during short-term preservation in dromedary camel. In experiment 1, 9 ejaculates from 3 bulls were diluted in the base extender with different concentrations of NAC (0, 6, 12, and 24 mM). The viscosity reduction was investigated at 5, 15, 30, and 120 min and 24 h post-dilution. In the second experiment, 15 ejaculates from 5 dromedary bulls were diluted with an extender containing 0, 6, and 12 mM of NAC, and viability, motility, and kinematics, as well as functional and DNA integrity of spermatozoa, were evaluated at 2, 12, 24, and 48 h of chilled storage at 5 °C. Experiment 3 evaluated the effect of adding NAC in the semen extender by carrying out 60 inseminations with 26- and 48-hour chilled semen. The pregnancy rates were compared between NAC and the control extender. Adding NAC to the extender resulted in a significant drop in viscosity compared to the raw and extended samples at all evaluation time points with a dose-dependent effect (P 0.05). At the same time, concentrations greater than 6 mM lowered viability, motility, and functionality of sperm from 12 h post-dilution (P < 0.05). Chilled sperm in the EXT+NAC 6 mM showed a marked improvement in DNA integrity status from 2 h post dilution onwards, with better motility and functional integrity at 48 h compared to the control (P < 0.05). Pregnancy rates with 26 h of chilled semen were similar between NAC-treated sperm and the control (33.33% vs. 38.09%, respectively; P > 0.05), corroborating the safety of NAC regarding its effect on sperm fertilizing capacity. In conclusion, adding NAC to the semen extender at concentrations of 6 mM assists with the liquefaction of dromedary semen without compromising sperm quality during subsequent storage in chilled status.

PSV-9 Cold Exposure Impacts Dna Methylation Patterns of Genes in Cattle Sperm Involved in Early Embryonic and Bone Development

Abstract DNA methylation and other epigenetic modifications are indispensable for maintaining sperm quality, fertilization capacity, and embryonic and postnatal development. In mice, environmental factors, such as stress, nutrition, or exposure to the cold condition, have been demonstrated as factors that alter methylation marks of sperm that are passed to the subsequent generation through transgenerational inheritance and genomic imprinting. Breeding bulls from northern regions of the USA are exposed to extreme cold for 2 to 3 months during the winter; however, no single study has analyzed the consequences of this cold exposure on the methylation pattern of bull sperm, which constitutes a significant knowledge gap. Therefore, this study aimed to explore the effects of cold exposure on the overall and gene-specific methylation status in sperm. We collected semen from 5 bulls during winter seasons after cold exposure and at normal temperatures during late spring. Whole Genome Bisulfite Sequencing (WGBS) was conducted to obtain the DNA methylation profile of these semen samples and to identify unique genes that have differentially methylated regions due to cold exposure (Figure 1). Cold exposure did not change the overall methylation level between the two groups but induced 438 Differentially methylated regions (DMRs) that overlapped with promoters, introns, exons, intergenic regions, shores, and shelves of CpG island (CGI) in 186 unique genes. We also identified nine unique differentially methylated genes (DMGs) (Pax6, Macf1, Mest, Ubqln1, Smg9, Trappc9, Ctnnb1, Lsm4, Peg10) involved in embryonic development and nine unique DMGs (Prmt6, Nipal1, C21h15orf40, Slc37a3, Fam210a, Raly, Rgs3, Lmbr1, Gan) involved in osteogenesis (Table 1). DMRs were located in the promoter regions and introns of these genes which preferentially involve gene silencing and alternative splicing. Among the DMGs involved in embryonic development, Mest and Peg10 are two paternally imprinted genes where only the paternal allele expresses. Peg10, required for optimal placental growth and trophoblast proliferation, overlapped with a hypermethylated DMR in the promoter region. Mest, another paternally imprinted gene, the downregulation of which results in embryonic growth retardation, had hypermethylation in introns. Moreover, Methylation-specific PCR (MS-PCR) verified the methylation changes in the identified regions. It was the first study to investigate the effect of cold exposure on DNA methylation of cattle sperm and suggest its association with altered sperm DNA methylation profiles. Differential methylation appears to alter gene expression and affect early embryonic development, osteogenic activity, and overall offspring growth performance through the imprinting effects.

Integrated transcriptomics and proteomics assay identifies the role of FCGR1A in maintaining sperm fertilization capacity during semen cryopreservation in sheep.

Semen cryopreservation is a promising technology employed in preserving high-quality varieties in animal husbandry and is also widely applied in the human sperm bank. However, the compromised qualities, such as decreased sperm motility, damaged membrane structure, and reduced fertilization competency, have significantly hampered the efficient application of this technique. Therefore, it is imperative to depict various molecular changes found in cryopreserved sperm and identify the regulatory network in response to the cryopreservation stress. In this study, semen was collected from three Chinese Merino rams and divided into untreated (fresh semen, FS) and programmed freezing (programmed freezing semen, PS) groups. After measuring different quality parameters, the ultra-low RNA-seq and tandem mass tag-based (TMT) proteome were conducted in both the groups. The results indicated that the motility (82.63% ± 3.55% vs. 34.10% ± 2.90%, p < 0.05) and viability (89.46% ± 2.53% vs. 44.78% ± 2.29%, p < 0.05) of the sperm in the FS group were significantly higher compared to those in the PS group. In addition, 45 upregulated and 291 downregulated genes, as well as 30 upregulated and 48 downregulated proteins, were found in transcriptomics and proteomics data separately. Moreover, three integrated methods, namely, functional annotation and enrichment analysis, Pearson's correlation analysis, and two-way orthogonal partial least squares (O2PLS) analysis, were used for further analysis. The results suggested that various differentially expressed genes and proteins (DEGs and DEPs) were mainly enriched in leishmaniasis and hematopoietic cell lineage, and Fc gamma receptor Ia (FCGR1A) was significantly downregulated in cryopreserved sperm both at mRNA and protein levels in comparison with the fresh counterpart. In addition, top five genes (FCGR1A, HCK, SLX4, ITGA3, and BET1) and 22 proteins could form a distinct network in which genes and proteins were significantly correlated (p < 0.05). Interestingly, FCGR1A also appeared in the top 25 correlation list based on O2PLS analysis. Hence, FCGR1A was selected as the most potential differentially expressed candidate for screening by the three integrated multi-omics analysis methods. In addition, Pearson's correlation analysis indicated that the expression level of FCGR1A was positively correlated with sperm motility and viability. A subsequent experiment was conducted to identify the biological role of FCGR1A in sperm function. The results showed that both the sperm viability (fresh group: 87.65% ± 4.17% vs. 75.8% ± 1.15%, cryopreserved group: 48.15% ± 0.63% vs. 42.45% ± 2.61%, p < 0.05) and motility (fresh group: 83.27% ± 4.15% vs. 70.41% ± 1.07%, cryopreserved group: 45.31% ± 3.28% vs. 35.13% ± 2.82%, p < 0.05) were significantly reduced in fresh and frozen sperm when FCGR1A was blocked. Moreover, the cleavage rate of embryos fertilized by FCGR1A-blocked sperm was noted to be significantly lower in both fresh (95.28% ± 1.16% vs. 90.44% ± 1.56%, p < 0.05) and frozen groups (89.8% ± 1.50% vs. 82.53% ± 1.53%, p < 0.05). In conclusion, our results revealed that the downregulated membrane protein FCGR1A can potentially contribute to the reduced sperm fertility competency in the cryopreserved sheep sperm.

P-046 Sperm mitochondrial DNA copy number and mitochondrial function in normozoospermic men may predict fertilization rates after intracytoplasmic sperm injection

Abstract Study question Do sperm mitochondrial DNA copy number (mtDNAcn) and mitochondrial function correlate with fertilization rates after intracytoplasmic sperm injection (ICSI)? Summary answer We reveal a negative correlation between sperm mtDNAcn and fertilization rates after ICSI, while higher mitochondrial function corresponded to an increase in sperm fertilization capacity. What is known already Over 40% of male-factor infertility is of unknown origin (unexplained and idiopathic in nature). As current diagnoses remain largely descriptive, the identification of markers predicting the fertilization capacity of sperm will hold the key towards improved treatment. Mitochondria are fundamental for supporting spermatogenesis and fertilization. A recent study showed that altered levels of sperm mitochondrial proteins led to oocyte-activation deficiency, resulting in fertilization failure after ICSI. Poor semen parameters have also been linked to high mtDNAcn, however the relationship between mtDNAcn in sperm and oocyte-activation capacity remains unexplored. Further characterization may uncover prognostic markers associated with sperm-related fertilization failure. Study design, size, duration Twenty normozoospermic semen samples were included in the study. These were obtained from oocyte donation ICSI cycles, performed between March 2021 and November 2022. Both fresh and cryopreserved sperm samples were analysed. Five million sperm were collected from the fresh ejaculate for genomic DNA (gDNA) isolation and mtDNAcn quantification, while the remainder of the sample was used for mitochondrial functional analysis. These analyses were also performed on washed samples, cryopreserved after swim-up. Participants/materials, setting, methods Mean paternal age and BMI were 40 ± 5.8 years and 25 ± 2.3 kg/m2, respectively. We evaluated mtDNAcn using qPCR, by assessing the ratio of mitochondrial-to-nuclear genes (NT-ND4/B2M). For our functional studies, we quantified mitochondrial membrane potential (MMP) in individual spermatozoa by JC-1 staining and flow cytometry. Flow cytometry analysis was performed on ≥ 10 million sperm treated with a mitochondrial uncoupler for 15 minutes (1 µM trifluoromethoxy-carbonylcyanide-phenylhydrazone, FCCP) and controls. Spearman correlation was applied. Main results and the role of chance We observed variable fertilization rates in our cohort (69.0 ± 24.9%). One sperm sample resulted in total fertilization failure (TFF) after ICSI and was analyzed independently. In fresh samples, mtDNAcn (5.8 AU ± 2.61) correlated negatively with progressive motility (rs = -0.65) and fertilization rate (rs = -0.32). Notably, the sample resulting in TFF presented with the highest mtDNAcn value (13.9 AU ± 2.77). Flow cytometry analysis revealed two distinct sperm populations, corresponding to motile and immotile sperm. While immotile sperm presented with low or undetectable JC-1 aggregates (red signal), motile sperm showed different levels of MMP (ratio INTred/INTgreen) (2.3 AU ± 1.83). In motile sperm, our results revealed a positive correlation between MMP and fertilization rate (rs = 0.59). As with raw semen, we observed a negative association between MMP and mtDNAcn in motile sperm (rs = -0.53). Limitations, reasons for caution Cryopreservation is known to affect sperm motility and active mitochondria in sperm, however its effect on MMP intensity remains to be established. Our limited sample size warrants careful interpretation. Wider implications of the findings Our findings suggest a negative correlation between sperm mtDNAcn and fertilization rates after ICSI, while fertilization capacity improved with increasing MMP. Sperm mtDNAcn and MMP may have prognostic value for male fertility and ICSI outcomes. Further validation may deliver clinically useful markers, aiding infertility diagnosis, treatment and counselling. Trial registration number NA

Aerobic exercises regulate the epididymal anion homeostasis of high-fat diet-induced obese rats through TRPA1-mediated Cl- and HCO3- secretion†.

Aerobic exercises could improve the sperm motility of obese individuals. However, the underlying mechanism has not been fully elucidated, especially the possible involvement of the epididymis in which sperm acquire their fertilizing capacity. This study aims to investigate the benefit effect of aerobic exercises on the epididymal luminal milieu of obese rats. Sprague-Dawley male rats were fed on a normal or high-fat diet (HFD) for 10 weeks and then subjected to aerobic exercises for 12weeks. We verified that TRPA1 was located in the epididymal epithelium. Notably, aerobic exercises reversed the downregulated TRPA1 in the epididymis of HFD-induced obese rats, thus improving sperm fertilizing capacity and Cl- concentration in epididymal milieu. Ussing chamber experiments showed that cinnamaldehyd (CIN), agonist of TRPA1, stimulated an increase of the short-circuit current (ISC) in rat cauda epididymal epithelium, which was subsequently abolished by removing the ambient Cl- and HCO3-. In vivo data revealed that aerobic exercises increased the CIN-stimulated Cl- secretion rate of epididymal epithelium in obese rats. Pharmacological experiments revealed that blocking cystic fibrosis transmembrane regulator (CFTR) and Ca2+-activated Cl- channel (CaCC) suppressed the CIN-stimulated anion secretion. Moreover, CIN application in rat cauda epididymal epithelial cells elevated intracellular Ca2+ level, and thus activate CACC. Interfering with the PGHS2-PGE2-EP2/EP4-cAMP pathway suppressed CFTR-mediated anion secretion. This study demonstrates that TRPA1 activation can stimulate anion secretion via CFTR and CaCC, which potentially forming an appropriate microenvironment essential for sperm maturation, and aerobic exercises can reverse the downregulation of TRPA1 in the epididymal epithelium of obese rats.

Review: Evaluation of bull fertility. Functional and molecular approaches.

With the term "assisted reproduction technologies" in modern cattle farming, one could imply the collection of techniques that aim at the optimal use of bovine gametes to produce animals of high genetic value in a time- and cost-efficient manner. The accurate characterisation of sperm quality plays a critical role for the efficiency of several assisted reproduction-related procedures, such as sperm processing, in vitro embryo production and artificial insemination. Bull fertility is ultimately a collective projection of the ability of a series of ejaculates to endure sperm processing stress, and achieve fertilisation of the oocyte and production of a viable and well-developing embryo. In this concept, the assessment of sperm functional and molecular characteristics is key to bull fertility diagnostics and prognostics. Among others, functional features linked to sperm plasma membrane, acrosome and DNA integrity are usually assessed as a measure of the ability of sperm to express the phenotypes that will allow them to maintain their homeostasis and orchestrate-in a strict temporal manner-the course of events that will enable the delivery of their genetic content to the oocyte upon fertilisation. Nevertheless, measures of sperm functionality are not always adequate indicators of bull fertility. Nowadays, advancements in the field of molecular biology have facilitated the profiling of several biomolecules in male gametes. The molecular profiling of bovine sperm offers a deeper insight into the mechanisms underlying sperm physiology and, thus, can reveal novel candidate markers for bull fertility prognosis. In this review, the importance of three organelles (the nucleus, the plasma membrane and the acrosome) for the characterisation of sperm fertilising capacity and bull fertility is discussed at functional and molecular levels. In particular, information about sperm head morphometry, chromatin structure, viability as well as the ability of sperm to capacitate and undergo the acrosome reaction are presented in relation to the cryotolerance of male gametes and bull fertility. Finally, major spermatozoal coding and non-coding RNAs, and proteins that are involved in the above-mentioned aspects of sperm functionality are also summarised.

Proteomic analysis reveals the potential positive effects of Mito-TEMPO on ram sperm motility and fertility during cryopreservation

The aim of this study was to investigate the effects of mitochondria-targeted antioxidant Mito-TEMPO on the protein profile of ram sperm during cryopreservation and evaluate the cryoprotective roles of Mito-TEMPO on ram sperm quality and fertilization capacity. Semen collected from 8 Dorper rams was cryopreserved in TCG-egg yolk extender supplemented with various concentrations of Mito-TEMPO (0, 20, 40 and 60 μM). After thawing, sperm characteristics, antioxidant status and the abundance of hexose transporters (GLUT 3 and 8) were analyzed. The cervical artificial insemination (AI) was performed to evaluate the fertilization ability of cryopreserved ram sperm. The alterations of sperm proteomic profile between the control and MT40 groups were determined using iTRAQ-coupled LC-MS. Supplementation with 40 μM of Mito-TEMPO resulted in the highest post-thaw sperm motility and kinematics. Sperm quality, antioxidant capacity and glucose transporter abundance of frozen-thawed ram sperm were elevated in the MT40 group. The inclusion of 40 μM Mito-TEMPO in freezing extender also resulted in the higher pregnancy rate of ewes. A total of 457 proteins including 179 upregulated proteins and 278 downregulated proteins were defied as differentially expressed proteins (DEPs) using fold change (FC) > 1.2 with P < 0.05. Sixty-one DEPs with (FC > 1.5) were dramatically regulated by Mito-TEMPO. These DEPs are mainly involved in sperm motility, energy metabolism and capacitation. Our data suggest that the beneficial effects of Mito-TEMPO on sperm motility and fertility potential of cryopreserved ram semen are achieved by regulating sperm antioxidant capacity and sperm proteins related to energy metabolism and fertility.

Effects of preconception exposure to phthalates on mouse sperm capacitation parameters.

Phthalates have been linked to adverse male reproductive health, including poor sperm quality and embryo quality as well as a longer time to pregnancy (months of unprotected intercourse before conception occurs). The present study aimed to evaluate the effect of preconception exposure to two ubiquitous phthalate chemicals, di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), and their mixture on sperm function, fertilization, and embryo development in mice. Adult male C57BL/6Jmice aged 8-9weeks were exposed to di(2-ethylhexyl) phthalate, di-n-butyl phthalate, or their mixture (di-n-butyl phthalate+di(2-ethylhexyl) phthalate) at 2.5mg/kg/day or vehicle for 40days (equivalent to one spermatogenic cycle) via surgically implanted osmotic pumps. Caudal epididymal spermatozoa were extracted and analyzed for motility using computer-assisted sperm analyses. Sperm phosphorylation of protein kinase A substrates and tyrosine phosphorylation, markers of early and late capacitation events, respectively, were analyzed by Western blots. In vitro fertilization was used to evaluate the sperm fertilizing capacity. While the study did not reveal any significant differences in sperm motility and fertilization potential, abnormal sperm morphology was observed in all phthalate exposures, particularly in the phthalate mixture group. In addition, the study revealed significant differences in sperm concentration between control and exposed groups. Moreover, protein phosphorylation of protein kinase A substrates was decreased in the di(2-ethylhexyl) phthalate and mixture exposure groups, while no significant changes in protein tyrosine phosphorylation were observed in any of the groups. Assessment of the reproductive functionality did not reveal significant effects on in vitro fertilization and early embryo development rates but showed wide variability in the phthalate mixture group. Our findings suggest that preconception phthalate exposure affects sperm numbers and phosphorylation of protein kinase A substrates involved in capacitation. Future research is warranted to examine the associations between phthalate exposure and capacitation in human spermatozoa.

Lipid peroxidation in avian semen.

The main cause of sperm chromatin damage is oxidative stress related to embryo development failure and adult infertility in mammals and also avian. Oxidative stress results in lipid peroxidation (LPO) causing cell damage. Lipid peroxidation is the oxidation of polyunsaturated fatty acids (PUFAs) in biological systems and causes changes in the physical structure and characteristics of the cell membrane. Due to the high amounts of PUFAs in the avian sperm membrane, its sperm seem susceptible to pe-roxidative damage and is a substantial factor in the fertilization capacity of sperm. The most commonly used methods for measuring LPO or its by-products, such as malondialdehyde (MDA) and 4-hydroksy-2-nonenal (4-HNE), in bird semen are based on the colorimetric method TBARS (thiobarbituric acid reactive substances) and on the use of a fluorescence probe (CC 11-BODIPY 581/591) as a marker to evaluate membrane lipid peroxidation. This review aims first to introduce LPO in avian semen and its effects on avian sperm and second to summarize the commonly applied methods of evaluating LPO and its damage in fresh and stored avian semen.

Seminal Extracellular Vesicles and Their Involvement in Male (In)Fertility: A Systematic Review.

Seminal plasma contains numerous extracellular vesicles (sEVs). Since sEVs are apparently involved in male (in)fertility, this systematic review focused on studies specifically investigating such relationship. Embase, PubMed, and Scopus databases were searched up to 31 December 2022, primarily identifying a total of 1440 articles. After processing for screening and eligibility, 305 studies were selected as they focused on sEVs, and 42 of them were considered eligible because they included the word fertility or a related word such as infertility, subfertility, fertilization, and recurrent pregnancy loss in the title, objective(s), and/or keywords. Only nine of them met the inclusion criteria, namely (a) conducting experiments aimed at associating sEVs with fertility concerns and (b) isolating and adequately characterizing sEVs. Six studies were conducted on humans, two on laboratory animals, and one on livestock. The studies highlighted some sEV molecules, specifically proteins and small non-coding RNAs, that showed differences between fertile and subfertile or infertile males. The content of sEVs was also related to sperm fertilizing capacity, embryo development, and implantation. Bioinformatic analysis revealed that several of the highlighted sEV fertility-related proteins would be cross-linked to each other and involved in biological pathways related to (i) EV release and loading and (ii) plasma membrane organization.

Antigen Unmasking Is Required to Clinically Assess Levels and Localisation Patterns of Phospholipase C Zeta in Human Sperm.

Mammalian oocyte activation is initiated by intracellular calcium (Ca2+) oscillations, driven by the testis-specific phospholipase C zeta (PLCζ). Sperm PLCζ analysis represents a diagnostic measure of sperm fertilisation capacity. The application of antigen unmasking/retrieval (AUM) generally enhanced the visualisation efficacy of PLCζ in mammalian sperm, but differentially affected the PLCζ profiles in sperm from different human males. It is unclear whether AUM affects the diagnosis of PLCζ in human sperm. Herein, we examined whether the application of AUM affected the correlation of PLCζ profiles with sperm parameters and fertilisation capacity. PLCζ fluorescence levels and localisation patterns were examined within the sperm of males undergoing fertility treatment (55 patients aged 29-53) using immunofluorescence in the absence/presence of AUM. The changes in PLCζ profiles following AUM were examined in relation to sperm health and fertilisation outcome. AUM enhanced the observable levels and specific localisation patterns of PLCζ in relation to both optimal sperm parameters and fertilisation outcome, without which significant differences were not observed. The extent of the change in levels and localisation ratios of PLCζ was also affected to a larger degree in terms of the optimal parameters of sperm fertility and fertilisation capacity by AUM. Collectively, AUM was essential to accurately assesses PLCζ in human sperm in both scientific and clinical contexts.

ECONOMIC EFFICIENCY OF THE INCLUSION OF VARIOUS DOSES OF THE FEED ADDITIVE NANOPLANT CHROME (K) IN THE DIET OF SIRE BULLS

As a result of the studies, it was established that the use of the feed additive Nanoplant Chrome (K) (0.2 mg per 1 kg of dry matter) in feeding sire bulls contributes to an increase in the economic efficiency of obtaining sperm production by 11.0% due to an increase in the volume of ejaculate by 4.6%, sperm activity – by 2.5%, sperm concentration – by 7.9%, the number of frozen sperm doses – by 10.1%, sperm fertilization capacity – by 4.1 pp, and a decrease in the number of rejected frozen sperm doses – by 0.6-0.8 pp.

Role of the hypothalamus in ghrelin effects on reproduction: sperm function and sexual behavior in male mice.

Ghrelin signals to the hypothalamus inhibit reproduction during times of food scarcity. In this study, we demonstrate that ghrelin impairs sperm quality in male mice. Ghrelin (GHRL) is an orexigenic peptide that has been investigated as one of the signals responsible for the reproductive performance of mammals under fluctuating metabolic conditions. Central GHRL administration impairs spermatogenesis in mice by regulating the hypothalamic-pituitary-gonadal axis function. In the present study, the hypothalamus role as a mediator of GHRL effects on sperm fertilizing capacity and male sexual behavior was evaluated. After 42 days of hypothalamic GHRL infusion or artificial cerebrospinal fluid, in vitro and in vivo sperm fertilizing capacity, testicular α-tubulin, speriolin gene expression and spermatic α-tubulin protein were evaluated. Hypothalamic expression of genes Kiss1, Gpr54 and Gnrh was also studied. The second group of animals was infused with one time only GHRL or artificial cerebrospinal fluid into the hypothalamus to evaluate the effects on sexual behavior. Results demonstrated that chronic GHRL administration to male mice significantly increased the percentages of pre-implantation embryo loss and the number of post-implantation embryo loss. In relation to the gene expression, our results show a relative decrease of Kiss1, Gpr54 and Spatc1. Although no significant differences were observed in the quantitative expression of α-tubulin protein, qualitative changes in its expression pattern were observed. In addition, a dual effect on sexual behavior was observed: 40% of the treated animals showed a significant reduction in the number of mounts and intromissions, while a 60% showed a significant decrease in ejaculation latency vs control animals. In conclusion, our results provide evidence that central GHRL administration possibly induces failure in embryo development and/or implantation in the females mated with treated males, possibly because of a negative effect in the α-tubulin pattern.

The secretion and metabolism of cumulus cells support fertilization in the bovine model

The cumulus oophorus is a structure that surrounds the mammalian egg and plays a key role in fertilization. However, very little is known with regards to how secretions from the cumulus cells can specifically promote fertilization. We hypothesized that secretions from bovine cumulus cells, and the reduction of oxygen stress by metabolic change, would enhance the fertilization capacity of sperm during in vitro fertilization (IVF) procedures. To prove our hypothesis, sperm were pre-incubated in chemically defined capacitation media containing methyl-beta-cyclodextrin and used to inseminate cumulus cell oocyte complexes, or denuded oocytes, with some components. While sperm capacitation was induced in capacitation media, fertilization was impeded by the removal of cumulus cells from cumulus cell oocyte complexes. Secretions from cumulus cells promoted the formation of two pronuclei via a filter and the fertilization of denuded oocytes was dramatically enhanced with hyaluronate, low oxygen concentration, or progesterone in fertilization media (P < 0.05). This demonstrates that these factors-maintained sperm motility and capacitation or enhanced the hyper-activation of capacitated sperm (P < 0.05). We conclude that cumulus cells secrete progesterone, hyaluronate and undergo metabolic events to reduce oxidative stress in fertilization media. These phenomenons help to improve the fertilization capacity of sperm. We believe that this study makes a significant contribution to our understanding of the function of cumulus cells during fertilization in animals and humans.

Oxidative Stress-Related Semen Quality and Fertility in the Male Arabian Yellowfin Sea Bream (Acanthopagrus arabicus) Fed a Selenium Nanoparticle-Supplemented Plant Protein-Rich Diet

A three-month research was conducted to evaluate the influence of supplementing a plant protein- (PP-) rich diet (60% of fish meal (FM) was replaced with a mixture of alternative PP sources) with selenium nanoparticles (Se-N) on sperm kinetics, fertilization capacity, and antioxidative responses in Arabian yellowfin sea bream (Acanthopagrus arabicus) males. In this point, graded levels of Se-N at 0, 0.5, 1, 2, and 4 mg/kg were added to the PP-rich diet. Also, a FM-based diet was used as a positive control. Two hundred and eighty-eight brooders (males:195.3±10.8 g and females:237.5±8.1 g;mean±standard error) were randomly distributed into eighteen 10 m3 rectangular concrete tanks (8 males: 8 females in each tank), and every three tanks were fed with one of the experimental feeds for three months. The seawater temperature and salinity were 18-22°C and 40-41‰, respectively, during the husbandry period. Selenium retention increased in the liver, testes, and semen of males with increasing dietary Se-N level (P&lt;0.05). Sperm density in fish fed with 2 mg Se-N/kg PP-rich diet (42.1×109/mL) was higher than those fed control, 0, 0.5, and 1 mg Se-N/kg PP-rich diets. The percentages of sperm motility in 60 s and 300 s after activation, sperms with straight movement, the longevity of sperm motility, and fertilization rate increased with increasing Se-N level in the PP-rich diets (P&lt;0.05). The highest and lowest semen superoxide dismutase activities were in fish fed 4 and 2 mg Se-N/kg PP-rich diets, respectively. The highest glutathione peroxidase activity in semen was in fish fed 4 mg Se-N/kg PP-rich diet, and the lowest values were in fish fed 0 and 0.5 mg Se-N/kg PP-rich diets. Total antioxidant capacity values in semen of fish fed 1 and 4 mg Se-N/kg PP-rich diets were higher than the other treatments. Fish fed with PP-rich diet without any Se-N supplementation had higher malondialdehyde level in the semen compared to the other groups. Results showed that supplementing PP-rich diet with 2-4 mg Se-N/kg can improve sperm kinetics and enhance fertility potential in A. arabicus males.