Acrosome Reaction Research Articles

Pharmacological inhibition of KSper impairs flagellar pH homeostasis of human spermatozoa.

Sperm-specific potassium channel (KSper) comprised of pore-forming subunit SLO3 and auxiliary subunit LRRC52 is of importance for sperm fertility. The deficiency of KSper in both mice and humans resulted in severe impairments of sperm functions including sperm hyperactivity and acrosome reaction. Previous reports suggested that mouse KSper modulated sperm function possibly by affecting sperm intracellular pH (pHi). However, the precise signaling mechanism of human KSper (hKSper) on the regulation of sperm functions was largely unclear. To explore the regulatory role of hKSper on sperm flagellar pHi. More than 50 sperm donors were recruited during a period of 1 year. As reported in our previous work, we quantitatively measured flagellar pHi by employing a single-cell pH fluorescent recording on human spermatozoa loaded with pH indicator pHrodo Red. Three different hKSper antagonists including clofilium, quinidine, and a polyclonal antibody of LRRC52 (LID1) were utilized to evaluate the effect of hKSper inhibition on sperm flagellar pHi. Given the predominant role of hKSper on the regulation of membrane potential (Em), we first detected a considerable depolarization (about 25-30mV) of Em evoked by clofilium and quinidine. Subsequently, it was shown that flagellar pHi values of human spermatozoa were significantly decreased by the treatment of clofilium (50 µM, from 7.13±0.11 to 6.43±0.12), quinidine (500 µM, from 7.00±0.11 to 6.64±0.08) and LID1 (20 µg/mL, from 6.98±0.16 to 6.67±0.22). Moreover, we found that when human spermatozoa were pre-incubated with a high K+ solution (135mM), both the depolarization of Em and the acidification of flagellar pHi evoked by clofilium and quinidine were abolished. In addition, we found that extracellular substitution of N-methyl-D-glucamine for Na+ abolished pHi acidification induced by hKSper inhibition. Our results demonstrate that hKSper inhibition evokes flagellar pHi acidification of human spermatozoa, suggesting that flagellar pHi maintenance is an important signaling mechanism of hKSper on the regulation of sperm functions.

Effect of Viscosity in the Medium for Sperm Cryopreservation of Golden Eagle (Aquila Chrysaetos)

BACKGROUND: The development of assisted reproduction techniques for birds is useful for ex situ conservation but is limited. For the golden eagle ( Aquila chrysaetos ), only artificial insemination procedures using extenders developed over 50 years ago have been described. OBJECTIVE: To evaluate the effect of the viscosity of the cryopreservation medium on the acrosomal reaction ability of A. chrysaetos sperm. MATERIALS AND METHODS: Viscosity was determined in 45 ejaculates. A design using the Lake medium, 6% dimethylacetamide (DMA), and Ficoll (10%, 35%, and 45%) was developed to create conditions of viscosity that was lower, similar, and higher than those determined in fresh semen. RESULTS: The viscosity of fresh semen was 3.2320 mPa/s. In aliquots of the Lake medium supplemented with 6% DMA and 10%, 35%, and 45% Ficoll, the viscosities were 2.1698 mPa/s, 3.5393 mPa/s, and 6.1123 mPa/s, respectively. Post-thaw, in the aliquot with 10% Ficoll, 74% of sperm were alive, with 28% mobility, and 21% exhibited an acrosomal reaction with percentages that were significantly lower (P<0.05) than those observed in sperm frozen with 30% and 45% Ficoll. CONCLUSION: Viscosity has a positive influence on the viability of cryopreserved semen.

Effect of protein acetylation on capacitation of stallion sperm

Sperm capacitation is considered the main factor limiting conventional in vitro fertilization (IVF) in horses. A recent scientific breakthrough in sperm processing for IVF in horses has resulted in embryos and foals being produced; however, various aspects of the IVF process remain to be fully elucidated. Lysine acetylation has been shown to play a role in sperm capacitation in several species and the objective of this study was to detect and evaluate this process in the horse. Ejaculates of two stallions were collected and incubated in different conditions with deacetylase inhibitors to induce a hyperacetylation state. Although lysine acetylation was successfully detected in all experimental groups, sperm hyperacetylation could not be induced following incubation with deacetylase inhibitors. In addition, no hyperactivation was detected by kinematic sperm evaluation and tyrosine phosphorylation increased only in the positive control group. Treatments with high doses of deacetylase inhibitors increased acrosome reaction indicating a possible connection between induction of acrosome reaction and protein acetylation. Future studies investigating the effect of longer incubation periods with different doses of deacetylase inhibitors are warranted to elucidate the ability of protein acetylation to induce capacitation of stallion sperm.

The regulation role of calcium channels in mammalian sperm function: a narrative review with a focus on humans and mice.

Mammalian sperm are characterized as specialized cells, as their transcriptional and translational processes are largely inactive. Emerging researches indicate that Ca2+ serves as a crucial second messenger in the modulation of various sperm physiological processes, such as capacitation, hyperactivation, and the acrosome reaction. Specifically, sperm-specific calcium channels, including CatSper, voltage-gated calcium channels (VGCCs), store-operated calcium channels (SOCCs), and cyclic nucleotide-gated (CNG) channels, are implicated in the regulation of calcium signaling in mammalian sperm. Calcium stores located in the sperm acrosomes, along with the IP3 receptors in the neck of the redundant nuclear envelope and the mitochondria in the tail, play significant roles in modulating intracellular Ca2+ levels in sperm. However, the functions and mechanisms of these calcium channels in modulating mammalian sperm physiological functions have not yet been well elucidated. Therefore, by focusing on humans and mice, this study aims to provide a comprehensive review of the current advancements in research regarding the roles of calcium signaling and associated calcium channels in regulating sperm function. This endeavor seeks to enhance the understanding of calcium signaling in sperm regulation and to facilitate the development of drugs for the treatment of infertility or as non-hormonal male contraceptives.

Guinea pig spermatozoa adhesion to an immobilized fibronectin matrix alters their physiology and increases their survival.

Isthmus is the region of the oviduct considered a reservoir for spermatozoa, where they are retained and then released synchronously with ovulation. Integrins mediate this interaction, and it is suggested that they regulate the viability and capacitation of spermatozoa. Spermatozoa retained in the oviductal epithelial cells show specific characteristics: normal morphology, intact acrosome and plasma membrane, no DNA fragmentation, and low levels of intracellular Ca2+ and protein phosphorylation at Tyr. This work aimed to define spermatozoa's ability to adhere to an immobilized fibronectin matrix and its effects on their viability and capacitation. We found that guinea pig spermatozoa showed a high affinity for adhering to an immobilized fibronectin matrix but not to those made up of type 1 collagen or laminin. This interaction was mediated by integrins that recognize the RGD domain. Spermatozoa adhered to an immobilized fibronectin matrix were maintained in a state of low capacitation: low levels of intracellular concentration of Ca2+, protein phosphorylation in Tyr and F-actin. Also, spermatozoa kept their plasma membrane and acrosome intact, flagellum beating, and showed low activation of caspases 3/7. The spermatozoa adhered to the immobilized fibronectin matrix, gradually detached, forming rosettes and did not undergo a spontaneous acrosomal reaction but were capable of experiencing a progesterone-induced acrosomal reaction. In conclusion, the adhesion of spermatozoa to an immobilized fibronectin matrix alters the physiology of the spermatozoa, keeping them in a steady state of capacitation, increasing their viability in a similar way to what was reported for spermatozoa adhered to oviductal epithelial cells.

Real-Time Imaging of Calcium Dynamics in Human Sperm After Precise Single-Cell Stimulation.

Calcium signaling is a critical regulator of sperm activation and function during the processes of capacitation and fertilization. Here, we describe a combined method for calcium imaging of single, live human sperm in response to stimuli administered with a precisely targeted delivery technique. This protocol is an adaptation of techniques developed for studies of murine sperm [1, 2], and enables real-time monitoring of human sperm calcium dynamics with high spatiotemporal resolution and concurrent detection of acrosome exocytosis (AE), a functional endpoint of sperm capacitation and requirement for physiological fertilization.The described imaging technique provides a valuable tool for exploration of calcium regulation in human sperm, which is essential to answer important questions and knowledge gaps regarding the link between calcium dynamics, AE, and fertilization. The versatility of this technique can be amplified through use of various indicator dyes or integration with pharmacological strategies such as pre-treating sperm with inhibitors or activators targeting specific receptors, channels, or intracellular signaling pathways of interest. Beyond fundamental inquiries into sperm physiology, this method can also be applied to assess the impact of potential contraceptive compounds on calcium signaling, AE, and membrane integrity.

Application of Autologous Platelet-rich Plasma Exerts Cryoprotective Effects on Biological Characteristics of Human Oligoasthenoteratospermia Samples after Freezing and Thawing Procedures.

Platelet-rich plasma (PRP) is enriched with active biological components which showed proliferative and cytoprotective properties in healing different injuries in medicinal fields. This study was designed to assess the cryoprotective effects of autologous PRP on the quality of oligoasthenoteratospermia (OAT) samples during freezing and thawing procedure. The present study is an experimental research. Twenty OAT semen samples were obtained from individuals and prepared by discontinuous density - gradients technique DGC). The control group is sperm samples after DGC. After the procedure, the specimen was divided into four groups. The Freeze group which has no additive and the other three groups were cryopreserved with different concentrations of PRP (1×105/ μL, 0.5×105/μL and 0.25×105/μL). Autologous PRP was provided by each participant. After thawing, sperm parameters, DNA fragmentation by sperm chromatin dispersion test (SCD), protamine deficiency by (Chromomycin A3) CMA3 staining, acrosome integrity and malondialdehyde (MDA) level were evaluated. Cryopreservation resulted in a significant decrease in all factors compared to the control group. There were no significant changes in sperm count, morphology, non-progressive motility and acrosome reaction by adding PRP as a cryoprotectant in comparison with the freeze group. PRP at all three concentrations showed a significant increase in progressive motility (3.05 ± 2.01 vs. 14.05 ± 4.13, 12.35 ± 4.90 and 12.15 ± 9.65, P < 0.001) and viability (36.85 ± 10.25 vs. 47.85 ± 5.86, 51.30 ± 5.54 and 50.05 ± 5.67, P < 0.001) compared to the sperm samples without PRP. The percentage of immotile sperms decreased at all PRP concentrations compared to the freeze group. Moreover, PRP at 1×105/μL concentration showed cryoprotective effects on DNA fragmentation, protamine deficiency and MDA level compared to the other three concentrations. Cryopreservation and thawing procedures may exert adverse effects on biological factors of sperm samples. Therefore, adding PRP as cryoprotectant at all three concentrations especially 1×105/μL can be promising strategy to reduce adverse effects of cryopreservation on OAT samples.

Integration analysis of transcriptome and metabolome revealed the potential mechanism of spermatogenesis in Tibetan sheep (Ovis aries) at extreme high altitude

Testis has an indispensable function in male reproduction of domestic animals. Numerous genes and metabolites were related to testicular development and spermatogenesis. However, little is known about the biological regulation pathways associated with fecundity in male Tibetan sheep. In this study, Testes were collected from Huoba Tibetan sheep (HB, 4614 m) and Gangba Tibetan sheep (GB, 4401 m) at extreme high altitude, and Alpine Merino sheep (AM, 2500 m, control group) at medium-high altitude, investigating the genes and metabolites levels of them. The histological analysis of testicular tissue using hematoxylin-eosin (HE) staining was performed for Tibetan sheep and Alpine Merino sheep, and the testes of them were analyzed by transcriptomics and metabolomics to explore the potential mechanism of testicular development and spermatogenesis. The statistical results showed that the cross-sectional area of testicular seminiferous tubules, diameter of seminiferous tubules, and spermatogenic epithelium thickness were significantly smaller in HB and GB than in AM (P < 0.05). Overall, 5648 differentially expressed genes (DEGs) and 336 differential metabolites (DMs) were identified in three sheep breeds, which were significantly enriched in spermatogenesis and other related pathways. According to integrated metabolomic and transcriptomic analysis, glycolysis/gluconeogenesis, AMPK signaling pathway, and TCA cycle, were predicted to have dramatic effects on the spermatogenesis of Tibetan sheep. Several genes (including Wnt2, Rab3a, Sox9, Hspa8, and Slc38a2) and metabolites (including L-histidinol, Glucose, Fumaric acid, Malic acid, and Galactose) were significantly enriched in pathways related to testicular development and spermatogenesis, and might affect the reproduction of Tibetan sheep by regulating the acrosome reaction, meiotic gene expression, and the production of sex hormones. Our results provide further understanding of the key genes and metabolites involved in testicular development and spermatogenesis in Tibetan sheep.

Bleomycin in vitro exposure decreases markers of human male gamete competence

To investigate the in vitro impact of bleomycin on human sperm DNA integrity, functionality, and morphology, with the aim of elucidating the underlying mechanism and anticipating potential repercussions on patients' reproductive function. Controlled laboratory-based in vitro investigation. Surplus human ejaculate donated for research by 45 reproductive-age participants exhibiting normozoospermic sperm parameters following clinical semen analysis. None of the participants had received a cancer diagnosis or undergone radiotherapy, chemotherapy, or both. After clinical semen analysis, sperm samples were centrifuged, diluted in sperm preparation medium (SPM), and exposed to bleomycin (100 μg/mL) for two hours at 37ºC in a humidified incubator with 5% CO2. In vitro human sperm competence was evaluated by comparing raw sperm, sperm incubated with SPM, and sperm exposed to bleomycin. Competence indicators included sperm motility, vitality, DNA and acrosome integrity, and mitochondrial membrane potential. Transmisson electron microscopy was employed to correlate the ultrastructural morphological findings with functional assays. Exposure to bleomycin for two hours in vitro significantly (P < 0.001) decreased sperm vitality, motility, and chromatin condensation compared to raw and control sperm. It also significantly (P < 0.001) increased sperm DNA fragmentation and the proportion of sperm with low mitochondrial membrane potential. Additionally, bleomycin significantly (P < 0.05) retarded the acrosomal response compared to control but did not affect the formation of intracellular and extracellular reactive oxygen species. Bleomycin-induced ultrastructural morphological changes supported the detected functional alterations. Bleomycin negatively impacts male gamete competency in humans. Healthcare professionals should vigilantly monitor and further investigate the gonadotoxicity effects of bleomycin, in addition to its recognized lung toxicity. Meanwhile, it is recommended that cancer patients undergoing bleomycin-containing chemotherapy regimens receive guidance on fertility preservation strategies.

Influence of free and microencapsulated recombinant rabbit nerve growth factor with chitosan on rabbit sperm quality parameters.

β-nerve growth factor (βNGF) plays a crucial role in reproductive physiology and sperm quality. Enzymatic activity of seminal plasma and vaginal fluids reduces available βNGF and it has been demonstrated that chitosan microspheres could protect rrβNGF from degradation. This study examined the effects of microencapsulated rrbNGF with chitosan on rabbit sperm viability, motility and capacitation status. Results showed that 0.5 and 1 μg/mL of microencapsulated rrβNGF, as well as free rrβNGF or empty microspheres, did not adversely affect sperm viability or total motility after 2 h of incubation. However, the highest progressivity kinetic parameters were observed with 1 μg/mL free rrβNGF, while the highest curvilinear velocity (VCL) occurred with 0.5 μg/mL microencapsulated rrβNGF. Empty chitosan microspheres did not induce acrosome reaction (AR), but both concentrations of free and rrβNGFch favoured AR during invitro incubation. The study suggests that using chitosan spheres did not show any adverse effects on sperm traits, unlike free rβNGF and rrβNGFch promoted capacitation and AR. Further research is needed to explore the potential of rrβNGFch in modifying invitro capacitation and inducing ovulation during artificial insemination.

Impact of semen cryopreservation season on invitro embryo production of prepubertal goat oocytes.

Goat production is affected by reproductive seasonality. Invitro embryo production (IVEP) could overcome this effect. This study aimed to evaluate the impact of the season of semen collection/freezing on IVEP of prepubertal goat oocytes and on sperm quality and functionality concerning capacitation. Semen from six fertile bucks was collected, pooled and cryopreserved in spring and autumn and used for IVEP of oocytes recovered during the breeding season. Oocytes were IVM in TCM-199 with hormones, EGF and cysteamine; fertilized and cultured in BO-IVF and BO-IVC media (IVF Bioscience, UK). Semen samples were assessed at 0 and 3 h after culture in capacitating (BO-IVF, CAP) and non-capacitating conditions for sperm plasma membrane and acrosome integrity, mitochondrial membrane potential (MMP), intracellular calcium and plasma membrane lipid disorder. Blastocyst production was higher with spring sperm compared to autumn (12.0% vs. 2.1%, respectively; p < .05). After CAP, acrosome reaction and intracellular calcium were higher (p < .05) in spring than autumn sperm. No differences were found in other sperm parameters. In conclusion, seasonal variations in the IVEP of prepubertal goats could be linked to differences in sperm ability to undergo invitro capacitation.

Differential abundance of microRNAs in seminal plasma extracellular vesicles (EVs) in Sahiwal cattle bull related to male fertility.

Sahiwal cattle, known for their high milk yield, are propagated through artificial insemination (AI) using male germplasm, largely contingent on semen quality. Spermatozoa, produced in the testes, carry genetic information and molecular signals essential for successful fertilization. Seminal plasma, in addition to sperm, contains nano-sized lipid-bound extracellular vesicles (SP-EVs) that carry key biomolecules, including fertility-related miRNAs, which are essential for bull fertility. The current study focused on miRNA profiling of SP-EVs from high-fertile (HF) and low-fertile (LF) Sahiwal bulls. SP-EVs were isolated using size exclusion chromatography (SEC) and characterized by dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). Western blotting detected the EV-specific protein markers TSG101 and CD63. The DLS analysis showed SP-EV sizes of 170-180nm in HF and 130-140nm in LF samples. The NTA revealed particle concentrations of 5.76 × 1010 to 5.86 × 1011 particles/mL in HF and 5.31 × 1010 to 2.70 × 1011 particles/mL in LF groups, with no significant differences in size and concentration between HF and LF. High-throughput miRNA sequencing identified 310 miRNAs in SP-EVs from both groups, with 61 upregulated and 119 downregulated in HF bull. Further analysis identified 41 miRNAs with significant fold changes and p-values, including bta-miR-1246, bta-miR-195, bta-miR-339b, and bta-miR-199b, which were analyzed for target gene prediction. Gene Ontology (GO) and KEGG pathway analyses indicated that these miRNAs target genes involved in transcription regulation, ubiquitin-dependent endoplasmic reticulum-associated degradation (ERAD) pathways, and signalling pathways. Functional exploration revealed that these genes play roles in spermatogenesis, motility, acrosome reactions, and inflammatory responses. qPCR analysis showed that bta-miR-195 had 80% higher expression in HF spermatozoa compared to LF, suggesting its association with fertility status (p < 0.05). In conclusion, this study elucidates the miRNA cargoes in SP-EVs as indicators of Sahiwal bull fertility, highlighting bta-miR-195 as a potential fertility factor among the various miRNAs identified.

DNAH17 deficiency causes disruption in the assembly and docking of sperm flagellar ODAs but not total fertilization failure after ICSI

Research questionAre there other variants in DNAH17 related to male infertility? What is the correlation between total fertilization failure and DNAH17 deficiency? DesignWhole-exome sequencing and Sanger sequencing were performed in a cohort of 75 Chinese patients with MMAF to identify potential novel gene variants. Papanicolaou staining and electron microscopy were employed to observe sperm morphology and ultrastructure. Proteomic analysis and comprehensive functional analysis were performed to elucidate the relationship between DNAH17 deficiency and total fertilization failure at the molecular level. ResultsTen novel variants in DNAH17 were identified in five unrelated families with six infertile males. These identified variants exhibited an autosomal recessive inheritance pattern and caused the deficiency of DNAH17 in sperm. Papanicolaou staining and electron microscopy demonstrated typical MMAF characteristics and deformations in flagellar ultrastructure of DNAH17-deficient sperm. Furthermore, our comprehensive functional analysis revealed that DNAH17 deficiency impaired the assembly and docking of ODAs, affected the acrosome reaction, and disrupted mitochondrial function. Interestingly, the fertilization-related proteins such as ACTL7A and PICK1 were normal, while reduced yet ≥30% PLCζ levels were detected, implying an indirect correlation between DNAH17 deficiency and total fertilization failure. Moreover, four of the affected couples got transferable embryos successfully through intracytoplasmic sperm injection (ICSI) without artificial oocyte activation (AOA). ConclusionsOur findings significantly broaden the variant spectrum of DNAH17 and illuminate the complex molecular basis of male infertility associated with DNAH17 deficiency, particularly its heterogeneous impact on fertilization. The favourable fertility outcomes of ICSI will provide vital insights for genetic diagnosis and counselling in males affected by MMAF.

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 &lt; 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 &lt; 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 &lt; 0.05). In simulated fertilization experiments, Exo-GPX5-treated sperm exhibited higher capacitation ability and a significant increase in the acrosome reaction rate (p &lt; 0.05). Overall, Exo-GPX5 can improve boar semen quality under 17 °C storage conditions and enhance sperm fertilization capacity.

A review of antioxidant strategies to improve reproduction in aging male broiler breeders.

As only 10% of the broiler breeder flock is roosters, their fertility is very important. The rooster sperm plasma membrane has high concentrations of polyunsaturated fatty acids that are sensitive to oxidative stress. Lipid peroxidation can change membrane structure, permeability, and fluidity, adversely affecting the acrosome reaction and fertility. Aging roosters have decreases in sexual behavior, serum androgen concentrations, sperm quantity and quality, and fertility. Low fertility in aging roosters is attributed to an imbalanced testicular oxidant-antioxidant system, with increased reactive oxygen species (ROS) damaging spermatogenic epithelium. However, antioxidant components can enhance antioxidant defenses in aging broiler breeder roosters. Protection against oxidative damage, particularly in the testes, improves reproductive hormone concentrations, testicular histology, sperm membrane function, and mitochondrial activity and thereby improves semen volume, sperm concentration, viability, motility, and sperm polyunsaturated fatty acid content, sperm-egg penetration, fertility, and reproductive performance. This review summarizes antioxidants that could improve fertility and reproductive performance and delay or prevent age-related declines in broiler breeder roosters, with benefits for poultry production.

Ascorbic acid 2-glucoside improves survival, quality, and fertility of frozen-thawed C57Bl/6J and C57Bl/6N mouse spermatozoa.

Ascorbic acid 2-glucoside (AA2G) is a stabilized form of ascorbic acid and a potent antioxidant. Ascorbic acid is present in the testes and epididymis and helps maintain the physiological integrity of reproductive organs. Its properties have been utilized to protect spermatozoa of different species from oxidative stress. Spermatozoa of C57Bl/6J and C57Bl/6N strains were frozen and analyzed, after thawing, by supplementing the capacitation medium with AA2G, both in the presence and absence of methyl-β-cyclodextrin (MBCD). The effect of treatment was evaluated by SCA System (Microptic) analyzing the velocity, vitality, morphology, and the DNA fragmentation. We also examined sperm capacitation (CTC), acrosome reaction (Coomassie Brillant Blue), and fertility (in vitro fertilization) of treated spermatozoa. AA2G improved sperm quality and fertility particularly in association with MBCD. We observed a significant increase of sperm motility, velocity, and vitality associated with an enhanced capacitation and acrosome reaction. These improvements resulted in a marked increase in in vitro fertilization success. Embryos obtained were cultured and reached normally the blastocyst stage. This study aimed to determine if AA2G could safeguard mouse spermatozoa during cryopreservation. We found a protective effect of AA2G that increased sperm survivability resulting in higher fertilization rate. This newly improved protocol shows potential for reanimating cryopreserved GEMMs stored in mouse biobanks and international repositories, such as the European Mouse Mutant Archive (EMMA). This can serve as a pivotal tool in fulfilling the 3Rs mission (replacement, reduction, and refinement), promoting ethical and humane research practices.

Exploring the Effects of Nitric Oxide and Reactive Oxygen Species on Buffalo Sperm Quality: A Comprehensive Review

Buffalo reproduction plays a vital role in the livestock industry, where sperm quality is a critical determinant of successful fertilization and overall fertility. Nitric oxide (NO) and reactive oxygen species (ROS) are key regulators of various physiological processes, including sperm function. However, their dual role in modulating sperm quality is complex, as both excessive and insufficient levels can lead to detrimental effects. This review explores the intricate balance between NO, ROS and sperm quality in buffalo, emphasizing the molecular mechanisms underlying these interactions. NO is a signaling molecule involved in the regulation of sperm motility, capacitation and acrosome reaction, but its overproduction can result in nitrosative stress, impairing sperm function. Similarly, ROS, at physiological levels, are essential for sperm capacitation and acrosome reaction, yet an imbalance towards oxidative stress can lead to lipid peroxidation, DNA fragmentation and reduced sperm viability. This review also delves into the role of exogenous NO donors, such as sodium nitroprusside (SNP), in modulating NO and ROS levels, and their consequent impact on sperm quality. The dual effects of NO and ROS on buffalo sperm highlight the importance of maintaining an optimal redox balance to preserve sperm integrity and functionality. In conclusion, understanding the molecular pathways through which NO and ROS influence sperm quality is crucial for developing targeted strategies to enhance reproductive outcomes in buffalo. Future research should focus on identifying biomarkers of oxidative stress and evaluating the potential of antioxidant therapies to mitigate the adverse effects of NO and ROS, ultimately improving buffalo fertility.

Evaluation of the effect of lecithin and nanolecithin in repairing membrane damage, maintaining membrane integrity, and improving human sperm function in the freezing-thawing process.

Our study aimed to evaluate the effects of lecithin nanoparticles on sperm quality during cryopreservation. In phase one, sperm-freezing media were prepared with lecithin concentrations (0.5%, 1%, and 2%) and lecithin nanoparticles of various sizes (50-100, 100-200, and ≥ 200nm). Post-thaw, sperm motility, viability, mitochondrial membrane potential (MMP), lipid peroxidation (measured by malondialdehyde, MDA), and DNA fragmentation were evaluated. In phase two, the acrosomal reaction was assessed in the best and worst-performing groups from phase one. DiI labeling detected interactions between lecithin nanoparticles and the sperm membrane. Field emission scanning electron microscopy (FESEM) examined the sperm membrane's surface structure and lecithin binding sites. Atomic force microscopy (AFM) assessed height differences in the sperm surface layer in the best-performing group from phase one. The group treated with 1% lecithin nanoparticles (50-100nm) showed significantly increased viability post-thaw compared to other groups, with reduced DNA fragmentation and MDA levels. While motility significantly decreased in all groups compared to before freezing levels, lower concentrations, and smaller particle sizes yielded better results. MMP also significantly decreased across all groups with no significant differences. The acrosomal reaction significantly decreased with 1% lecithin nanoparticles (50-100nm) compared to the 2% (≥ 200nm) group. DiI-labeled nanoparticles and FESEM revealed that lecithin nanoparticles primarily bound to and infiltrated the sperm membrane, particularly in the head and postacrosomal regions. Lecithin nanoparticles effectively bind to the sperm membrane, protecting it during the freeze-thaw process and improving sperm viability.

Lipid remodeling in acrosome exocytosis: unraveling key players in the human sperm.

It has long been thought that exocytosis was driven exclusively by well-studied fusion proteins. Some decades ago, the role of lipids became evident and escalated interest in the field. Our laboratory chose a particular cell to face this issue: the human sperm. What makes this cell special? Sperm, as terminal cells, are characterized by their scarcity of organelles and the complete absence of transcriptional and translational activities. They are specialized for a singular membrane fusion occurrence: the exocytosis of the acrosome. This unique trait makes them invaluable for the study of exocytosis in isolation. We will discuss the lipids' role in human sperm acrosome exocytosis from various perspectives, with a primary emphasis on our contributions to the field. Sperm cells have a unique lipid composition, very rare and not observed in many cell types, comprising a high content of plasmalogens, long-chain, and very-long-chain polyunsaturated fatty acids that are particular constituents of some sphingolipids. This review endeavors to unravel the impact of membrane lipid composition on the proper functioning of the exocytic pathway in human sperm and how this lipid dynamic influences its fertilizing capability. Evidence from our and other laboratories allowed unveiling the role and importance of multiple lipids that drive exocytosis. This review highlights the role of cholesterol, diacylglycerol, and particular phospholipids like phosphatidic acid, phosphatidylinositol 4,5-bisphosphate, and sphingolipids in driving sperm acrosome exocytosis. Furthermore, we provide a comprehensive overview of the factors and enzymes that regulate lipid turnover during the exocytic course. A more thorough grasp of the role played by lipids transferred from sperm can provide insights into certain causes of male infertility. It may lead to enhancements in diagnosing infertility and techniques like assisted reproductive technology (ART).

A century of andrology in Cell & Tissue Research: looking back while moving forward.

This article commemorates the 100th anniversary of the first issue of Cell & Tissue Research (CTR), the longest-running active journal dedicated to cell biology. Reflecting the significant contributions of spermatology and embryology to the early days of cell biology, the majority of articles in CTR's inaugural issue centered on plant and animal sperm cells. A brief synopsis of these articles provides a launching point for revisiting 100years of research on the male germ cells and fertility in humans and animals and offers a perspective on the current state and future directions of the andrology field. Early technological advances in light and electron microscopy enabled descriptive studies that ushered in the era of mechanistic, biochemistry-based inquiry focused on the understanding of physiological sperm processes such as sperm capacitation, acrosomal exocytosis, and sperm-egg interactions. In the last 20years, progress in flow cytometry, cell imaging, and omics revealed new information on sperm proteome, transcriptome, metabolome, and overall phenome of fertile and infertile spermatozoa. Going back to the journal's roots, recent advances in male germ cell isolation, transplantation, modification, and cryopreservation have been discussed on the pages of CTR. Newest trends such as gene editing and artificial intelligence/machine learning are now making inroads into andrological inquiry and assisted reproductive therapy of male infertility.