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This study was aimed at evaluating the effects of the commercial formulation Roundup Ultramax® on sperm mortality and viability, in terms of the capacity of spermatozoids (spz) to trigger the acrosome reaction (AR), using the estuarine crab Neohelice granulata as a model. To this, an in vivo assay comprising 100 days duration was carried out, on a control group and two groups exposed to the formulation (0.01 mg/L and 0.2 mg/L of glyphosate) under controlled conditions of photoperiod, feeding, and temperature. At the end of the assay, the right vas deferens (VD, proximal and middle portion) was dissected, and after homogenizing it in calcium-free saline solution, the acrosome reaction was induced in the phase containing the spz. In each treatment, the percentage of spz with total and partial AR was calculated, as well as that of dead spz. Compared to the control, crabs exposed to the herbicide showed a significant decrease in spz with full AR, together with an increase in the percentage of spz with partial AR. Furthermore, spz mortality was significantly higher in both glyphosate concentrations compared to the control, in a concentration-dependent manner. On the other hand, abnormal spermatophores, showing expanded walls and coalescence, were observed in a significant percentage in the left VD of the groups treated with the herbicide. The results obtained are compared with those from other studies on several invertebrate and vertebrate species that found inhibition of the AR and abnormal sperm, together with inhibition of spermatogenesis, endocrine disruption, and reduced sperm motility by effect of pure glyphosate and/or different glyphosate formulations. In summary, the available evidence highlights the possible impact of glyphosate on sperm quality, in a wide variety of species., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Premature acrosomal exocytosis in cryopreserved semen is one of the reasons attributed to low fertility among livestock. In the present study, we attempted to enhance the cryopreserved semen quality by selective removal of acrosome-reacted spermatozoa using FITC-PNA conjugated iron magnetic nanoparticles (MNPs). Further, the effect of nano purification on other sperm functional attributes was also assessed. Iron MNPs were prepared using co-precipitation method and dextran-coated MNPs were conjugated with FITC-PNA (0.04 mg/mL). A preliminary experiment was conducted to standardise the dose of FITC-PNA conjugated iron MNPs (0.02, 0.05, 0.1, 0.15, 0.2, 0.4 and 0.6 mg). Among the different doses used, 0.6 mg FITC-PNA conjugated iron MNPs significantly (p < 0.05) removed higher acrosomal reacted spermatozoa from the semen, and therefore, this dose was used in further experiments. Cryopreserved semen from Holstein Friesian breeding bulls (n = 6) were thawed and washed using Sperm-TALP to remove residual extender. Washed spermatozoa (2 × 10 6 ) were exposed to 0.6 mg of FITC-PNA conjugated iron MNPs for 10 min at 37°C. The nano purified semen was assessed for various vital sperm parameters viz., viability, intracellular calcium, apoptosis, mitochondrial ROS and mitochondrial membrane potential using flow cytometry. We found that nanopurification using FITC-PNA conjugated iron MNPs significantly (p < 0.05) improved the sperm quality. The proportion of viable non-apoptotic spermatozoa with low intracellular calcium levels was significantly (p < 0.05) enriched in nano purified semen. Nano purification did not affect sperm mitochondrial membrane potential and ROS production. In conclusion, these preliminary findings indicate that FITC-PNA coated iron MNPs effectively removed acrosome reacted spermatozoa and significantly improved sperm functional attributes in the purified fraction., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

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 in vitro 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 in vitro capacitation and inducing ovulation during artificial insemination., (© 2024 The Author(s). Reproduction in Domestic Animals published by Wiley‐VCH GmbH.)

Background: While calcium is known to play a crucial role in mammalian sperm physiology, how it flows in and out of the male gamete is not completely understood. Herein, we investigated the involvement of Na + /Ca 2+ exchangers (NCX) in mammalian sperm capacitation. Using the pig as an animal model, we first confirmed the presence of NCX1 and NCX2 isoforms in the sperm midpiece. Next, we partially or totally blocked Ca 2+ outflux (forward transport) via NCX1/NCX2 with different concentrations of SEA0400 (2-[4-[(2,5-difluorophenyl)methoxy]phenoxy]-5-ethoxyaniline; 0, 0.5, 5 and 50 µM) and Ca 2+ influx (reverse transport) with SN6 (ethyl 2-[[4-[(4-nitrophenyl)methoxy]phenyl]methyl]-1,3-thiazolidine-4-carboxylate; 0, 0.3, 3 or 30 µM). Sperm were incubated under capacitating conditions for 180 min; after 120 min, progesterone was added to induce the acrosome reaction. At 0, 60, 120, 130, and 180 min, sperm motility, membrane lipid disorder, acrosome integrity, mitochondrial membrane potential (MMP), tyrosine phosphorylation of sperm proteins, and intracellular levels of Ca 2+ , reactive oxygen species (ROS) and superoxides were evaluated., Results: Partial and complete blockage of Ca 2+ outflux and influx via NCX induced a significant reduction of sperm motility after progesterone addition. Early alterations on sperm kinematics were also observed, the effects being more obvious in totally blocked than in partially blocked samples. Decreased sperm motility and kinematics were related to both defective tyrosine phosphorylation and mitochondrial activity, the latter being associated to diminished MMP and ROS levels. As NCX blockage did not affect the lipid disorder of plasma membrane, the impaired acrosome integrity could result from reduced tyrosine phosphorylation., Conclusions: Inhibition of outflux and influx of Ca 2+ triggered similar effects, thus indicating that both forward and reverse Ca 2+ transport through NCX exchangers are essential for sperm capacitation., (© 2024. The Author(s).)

Protein glycosylation is a post-translational modification involved in wide range of biological processes. In mammalian spermatozoa this modification has been identified in numerous proteins, and membrane glycoproteins are involved in the fertilization process. The objective of the present study was to identify changes in protein glycosylation after acrosome reaction (AR) induction using the 4-Br-A23187 ionophore. Our results showed that treatment with 10 μM of 4-Br-A23187 for 20 min significantly increased the percentage of live acrosome-reacted spermatozoa compared to the control (69.8 ± 0.8 vs. 6.4 ± 0.5; mean % ± SEM, respectively). Also, we observed an increase in 32 kDa tyrosine-phosphorylated protein (p32) and a decrease in serine/threonine phosphorylation of the protein kinase A substrates (phospho-PKA-substrates) after ionophore treatment. Furthermore, changes in glycosylated proteins following AR induction were analyzed using different HRP-conjugated lectins (GNA, DSA, and SNA), revealing changes in mannose and sialic acid residues. Proteomic analysis of isolated proteins using GNA lectin revealed that 50 proteins exhibited significantly different abundance (q-value < 0.01). Subsequent analysis using Uniprot database identified 39 downregulated and 11 upregulated proteins in the presence of 4-Br-A23187. Notably, six of these proteins were classified as transmembrane proteins, namely LRRC37A/B like protein 1 C-terminal domain-containing protein, Membrane metalloendopeptidase like 1, VWFA domain-containing protein, Syndecan, Membrane spanning 4-domains A14 and Serine protease 54. This study shows a novel protocol to induce acrosome reaction in boar spermatozoa and identifies new transmembrane proteins containing mannose residues. Further work is needed to elucidate the role of these proteins in sperm-oocyte fusion., Competing Interests: Declaration of competing interest The authors have declared that no competing interests exist., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Exposure of humans and animals to heavy metals is increasing day-by-day; thus, lead even today remains of significant public health concern. According to CDC, blood lead reference value (BLRV) ranges from 3.5 µg/dl to 5 μg/dl in adults. Recently, almost 2.6% decline in male fertility per year has been reported but the cause is not well established. Lead (Pb 2+ ) affects the size of testis, semen quality, and secretory functions of prostate. But the molecular mechanism(s) of lead toxicity in sperm cells is not clear. Thus, present study was undertaken to evaluate the adverse effects of lead acetate at environmentally relevant exposure levels (0.5, 5, 10 and 20 ppm) on functional and molecular dynamics of spermatozoa of bucks following in vitro exposure for 15 min and 3 h., Results: Lead significantly decreased motility, viable count, and motion kinematic patterns of spermatozoa like curvilinear velocity, straight-line velocity, average path velocity, beat cross frequency and maximum amplitude of head lateral displacement even at 5 ppm concentration. Pb 2+ modulated intracellular cAMP and Ca 2+ levels in sperm cells through L-type calcium channels and induced spontaneous or premature acrosome reaction (AR) by increasing tyrosine phosphorylation of sperm proteins and downregulated mitochondrial transmembrane potential. Lead significantly increased DNA damage and apoptosis as well. Electron microscopy studies revealed Pb 2+ -induced deleterious effects on plasma membrane of head and acrosome including collapsed cristae in mitochondria., Conclusions: Pb 2+ not only mimics Ca 2+ but also affects cellular targets involved in generation of cAMP, mitochondrial transmembrane potential, and ionic exchange. Lead seems to interact with Ca 2+ channels because of charge similarity and probably enters the sperm cell through these channels and results in hyperpolarization. Our findings also indicate lead-induced TP and intracellular Ca 2+ release in spermatozoa which in turn may be responsible for premature acrosome exocytosis which is essential feature of capacitation for fertilization. Thus, lead seems to reduce the fertilizing capacity of spermatozoa even at 0.5 ppm concentrations., (© 2024. The Author(s).)

To acquire the ability to fertilize the egg, mammalian spermatozoa must undergo a series of changes occurring within the highly synchronized and specialized environment of the female reproductive tract, collectively known as capacitation. In an attempt to replicate this process in vitro, various culture media for mouse sperm were formulated over the past decades, sharing a similar overall composition but differing mainly in ion concentrations and metabolic substrates. The widespread use of the different media to study the mechanisms of capacitation might hinder a comprehensive understanding of this process, as the medium could become a confounding variable in the analysis. In this context, the present side-by-side study compares the influence of four commonly used culture media (FD, HTF and two TYH versions) on mouse sperm capacitation. We evaluated the induction of protein kinase A phosphorylation pathway, motility, hyperactivation and acrosome reaction. Additionally, in vitro fertilization and embryo development were also assessed. By analyzing these outcomes in two mouse colonies with different reproductive performance, our study provides critical insights to improve the global understanding of sperm function. The results obtained highlight the importance of considering variations in medium composition, and their potential implications for the future interpretation of results., (© 2024. The Author(s).)