Reactive oxygen species (ROS) play a dual role in mammalian spermatozoa. At high levels, they are detrimental to sperm function since they can promote oxidative stress that produces oxidation of protein, lipids, and sperm DNA. This oxidative damage is associated with male infertility. On the other hand, when ROS are produced at low levels, they participate in the redox signaling necessary for sperm capacitation. Capacitation-associated ROS are produced by the sperm oxidase, whose identity is still elusive, located in the plasma membrane of the spermatozoon. ROS, such as superoxide anion, hydrogen peroxide, nitric oxide, and peroxynitrite, activate protein kinases and inactivate protein phosphatases with the net increase of specific phosphorylation events. Peroxiredoxins (PRDXs), antioxidant enzymes that fight against oxidative stress, regulate redox signaling during capacitation. Among them, PRDX6, which possesses peroxidase and calcium-independent phospholipase A 2 (iPLA 2 ) activities, is the primary regulator of redox signaling and the antioxidant response in human spermatozoa. The lysophosphatidic acid signaling is essential to maintain sperm viability by activating the phosphatidylinositol 3-kinase/protein kinase (PI3K/AKT) pathway, and it is regulated by PRDX6 iPLA 2 , protein kinase C (PKC), and receptor-type protein tyrosine kinase. The understanding of redox signaling is crucial to pave the way for novel diagnostic tools and treatments of male infertility.
Humans ; Male ; Spermatozoa/physiology* ; Signal Transduction/physiology* ; Oxidation-Reduction ; Peroxiredoxins/physiology* ; Reactive Oxygen Species/metabolism* ; Oxidative Stress/physiology* ; Sperm Capacitation/physiology* ; Infertility, Male/metabolism*

Oocytes retrieval, in vitro maturation (IVM) and fertilization (IVF) efficiency are inevitable steps towards in vitro production of embryos. In the present study, these parameters were investigated in the ovaries of prepubertal (n = 31) and pubertal (n = 61) black Bengal goats obtained from a slaughterhouse. Nuclear maturation was evaluated upon aspiration and following IVM in TCM-199 (Earle's salt with L-glutamine and sodium bicarbonate) for 27 h at 39degrees C under 5% CO2 in humidified air. The oocytes retrieval and efficiency (mean +/- SD) per prepubertal and pubertal goats were 5.2 +/- 0.6 and 6.8 +/- 0.6, and 77.3 +/- 0.1% and 80.5 +/- 0.6%, respectively. Anaphase I - telophase I stages differed significantly (7.3 +/- 0.8 vs. 2.6 +/- 0.2, p < 0.05) between the two groups of goats. After IVM, the percentages of metaphase II were significantly higher (66.3 vs. 60.3, p < 0.05) in pubertal goats than in their prepubertal counterparts. The percentages of normal in vitro fertilization (IVF) in Fert-Tyrode's albumin lactate pyruvate of pubertal goat oocytes did not differ between Percoll and swim-up sperm separation methods (36.7 +/- 0.9% vs. 32.7 +/- 1.3%, p > 0.05). Furthermore, sperm capacitation by heparin alone or in combination with ionomycin did not lead to a significant increase in the normal fertilization rate (34.8 +/- 1.7 vs. 32.2 +/- 1.5%, respectively) in the oocytes of pubertal goats. In conclusion, the ovaries of pubertal black Bengal goats obtained from the slaughterhouse could be used for in vitro embryo production. However, further optimization of the IVM and IVF techniques are necessary for satisfactory in vitro embryo production.
Animals ; Culture Techniques ; Embryonic Development/*physiology ; Female ; Fertilization in Vitro/*veterinary ; Goats/*embryology ; Male ; Oocyte Retrieval/veterinary ; Oocytes/*physiology ; Ovary/cytology ; Sexual Maturation ; Sperm Capacitation ; Tissue and Organ Harvesting/veterinary

The sperm plasma membrane is rich in polyunsaturated fatty acids and a variety of proteins, and its function is associated with sperm capacitation, acrosome reaction and sperm-egg fusion. Sperm fertilizability can be predicted by detecting the function of the sperm plasma membrane, which is performed mainly with the following five techniques: sperm hypoosmotic swelling test, Eosin gamma water test, sperm membrane lipid peroxidation determination, seminal plasma superoxide dismutase determination, and flow cytometry. The evaluation of the function of sperm plasma membrane can be applied in detecting semen quality, selecting semen centrifugation, assessing the quality and fertilizability of sex-sorted sperm, improving cryopreservation, and guiding the optimization of intracytoplasmic sperm injection. This review presents an update on the principles, methods and steps of the detection of sperm plasma membrane function, as well as an overview of its status quo and application.
Cell Membrane ; physiology ; Flow Cytometry ; Humans ; Male ; Semen Analysis ; Semen Preservation ; Sperm Capacitation ; Sperm Injections, Intracytoplasmic ; Sperm Motility ; Spermatozoa ; physiology

Ion channels in mammal sperm, including Ca2+, Na+, K+, Cl- and HCO3- channels, each play a key role in the process of sperm capacitation. Ca2+, HCO3- and ROS, as signal molecules, activate soluble adenylyl cyclase (sAC) with the cooperation of cyclic adenosine monophosphate (cAMP), Ca2+ and intracellular pH and, via a cross talk between the cAMP/protein kinase A (PKA) and tyrosine phosphatase signaling pathways, promote the biological effect of sperm capacitation.
Animals ; Humans ; Ion Channels ; metabolism ; Ions ; metabolism ; Male ; Mammals ; Signal Transduction ; Sperm Capacitation ; physiology

Prior to fertilization sperm has to undergo an activation process known as capaciation, leading to the acrosome reaction. Till now, little is known about the mechanism for preventing premature capacitation in sperm although decapacitation factors from various sources have been thought to be involved. In this study, we report that NYD-SP27, an isoform of phospholipase C Zeta 1 (PLCZ1), is localized to the sperm acrosome in mouse and human spermatozoa by immunofluorescence using a specific antibody. Western blot and double staining analyses show NYD-SP27 becomes detached from sperm, as they undergo capacitation and acrosome reaction. The absence of HCO3-, a key factor in activating capacitation, from the capacitation-inducing medium prevents the loss of NYD-SP27 from sperm. The anti-NYD-SP27 antibody also prevents the loss of NYD-SP27 from sperm, reduced the number of capacitated sperm, inhibited the acrosome reaction induced by ATP and progesterone, and inhibited agonist-induced PLC-coupled Ca2+ mobilization in sperm, which can be mimicked by the PLC inhibitor, U73122. These data strongly suggest that NYD-SP27 is a physiological inhibitor of PLC that acts as an intrinsic decapacitation factor in sperm to prevent premature capacitation and acrosome reaction.
Acrosome ; drug effects ; metabolism ; Acrosome Reaction ; physiology ; Adult ; Animals ; Calcium ; metabolism ; Fluorescent Antibody Technique, Indirect ; Humans ; Immune Sera ; pharmacology ; Male ; Mice ; Middle Aged ; Phosphoinositide Phospholipase C ; immunology ; metabolism ; Sperm Capacitation ; drug effects ; physiology ; Spermatozoa ; drug effects ; metabolism

OBJECTIVETo evaluate the role of sperm kinematic parameters in the hyperactivation of Guinea pig spermatozoa, and to confirm the index of their hyperactivated motility.

METHODSComputer-aided sperm analysis (CASA) was used to describe the kinesis parameters of the Guinea pig spermatozoa incubated for 1, 3, 5 and 7 hours.

RESULTSThe curvilinear velocity, average path velocity and amplitude of lateral head displacement were increased with time and reached the peak at 5 hours, while the straight linear velocity, linearity, straightness and beat cross frequency were gradually decreased with time and hit the bottom at 5 hours.

CONCLUSIONThe sperm movement pattern changes greatly before hyperactivation during the capacitation of Guinea pig spermatozoa.

Animals ; Guinea Pigs ; Kinetics ; Male ; Numerical Analysis, Computer-Assisted ; Sperm Capacitation ; physiology ; Sperm Motility ; physiology ; Spermatozoa ; physiology

OBJECTIVETo investigate the possible involvement of calmodulin in mouse sperm capacitation.

METHODSCalmodulin antagonists W7 at the concentrations of 50, 100 and 200 micromol/L and calmidazolium (CZ) at the concentrations of 10, 20 and 30 micromol/ L, were coincubated with mouse sperm for 2 hours, respectively. The percentage of pattern B sperm was measured by chlorotetracycline staining. Then the sperm were coincubated with 100 micromol/L W7 or 10 micromol/L calmidazolium (CZ) before acrosome reaction was induced by 5 micromol/L progesterone and evaluated by the same method.

RESULTSAfter the treatment of the sperm with different concentrations of CZ or W7, the percentages of pattern B sperm decreased in a dose-dependent manner, significantly different from the control (P < 0.05). There was a statistic difference in the rate of acrosome reaction between the experiment and the control group (P < 0.01).

CONCLUSIONCalmodulin is a key protein involved in mouse sperm capacitation.

Animals ; Calmodulin ; antagonists & inhibitors ; Enzyme Inhibitors ; pharmacology ; Imidazoles ; pharmacology ; Male ; Mice ; Mice, Inbred ICR ; Sperm Capacitation ; drug effects ; Sperm Count ; Sperm Motility ; drug effects ; Spermatids ; cytology ; drug effects ; physiology

AIMTo investigate if the phytoestrogen, genistein, affects essential functions of cryopreserved bovine spermatozoa.

METHODSThe effect of genistein upon motility was assessed by computer-assisted motion analysis. Hemizona assay was performed to detect the ability of spermatozoa binding to the zona pellucida. The inducibility of the acrosome reaction using progesterone and ZP3-6 peptide was analysed by fluorescein-conjugated Pisum sativum agglutinin (FITC-PSA)/Hoechst 33258 double staining. Capacitation after incubation with genistein was assessed by the chlortetracycline (CTC) assay. Immunoblots showed the pattern of protein tyrosine phosphorylation of cryopreserved bovine spermatozoa.

RESULTSImmunodetection of tyrosine-phosphorylated proteins showed that genistein did not affect tyrosine phosphorylation in cryopreserved bovine spermatozoa. However, genistein significantly reduced the progesterone- and ZP3-6 peptide-mediated induction of the acrosome reaction and led to a dose-dependent inhibition of sperm-zona pellucida binding; while sperm motility and capacitation were not affected by this phytoestrogen, as indicated by computer-assisted sperm motion analysis and the CTC assay, respectively.

CONCLUSIONOur results suggest that in cryopreserved bovine spermatozoa, genistein affects a protein tyrosine phosphorylation-independent signal transduction pathway that is involved in sperm capacitation, the acrosome reaction and sperm-zona pellucida binding.

Acrosome Reaction ; drug effects ; physiology ; Animals ; Cattle ; Enzyme Inhibitors ; pharmacology ; Genistein ; pharmacology ; Male ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Sperm Capacitation ; drug effects ; physiology ; Zona Pellucida ; drug effects ; physiology

Epididymal maturation is associated with the activation of a cAMP-induced tyrosine phosphorylation cascade, which is ultimately associated with the expression of capacitation-dependent sperm functions, such as hyperactivated movement and acrosomal exocytosis. As spermatozoa progress through the epididymis they first acquire the capacity to phosphorylate tyrosine on targets on the principal piece, followed by the midpiece. By the time these cells have reached the cauda epididymidis they can phosphorylate the entire tail from neck to endpiece. This particular pattern of phosphorylation is associated with the ontogeny of fully functional spermatozoa that are capable of fertilizing the oocyte. Proteomic analyses indicate that this change is associated with the phosphorylation of several mitochondrial proteins, creation of a mitochondrial membrane potential and activation of mitochondrial free radical generation. At least in rodent species, activation of sperm mitochondria appears to be a particularly important part of epididymal maturation.
Acrosome Reaction ; Aging ; Animals ; Epididymis ; growth & development ; physiology ; Humans ; Male ; Mammals ; Mice ; Proteome ; Sperm Capacitation ; physiology ; Spermatozoa ; physiology

Rat protein DE is an androgen-dependent cysteine-rich secretory protein (CRISP) synthesized by proximal epididymal regions. DE, also known as CRISP-1, is localized on the equatorial segment of acrosome-reacted spermatozoa and participates in gamete fusion through binding to egg complementary sites. Immunization of rats with DE inhibits fertility and sperm fusion ability, suggesting that DE represents a good epididymal contraceptive target. Recombinant DE fragments and synthetic peptides revealed that DE binds to the egg via a 12-amino acid region of an evolutionarily conserved motif, Signature 2 (S2). The ability of other CRISP to bind to the rat egg was correlated with their S2 amino acid sequences. Although testicular protein Tpx-1 (CRISP-2) was capable of binding to rodent eggs, human epididymal AEG-related protein (ARP) and helothermine (from lizard saliva) were not. The S2 region presented only two substitutions in Tpx-1 and four in ARP and helothermine, compared with the DE S2, suggesting that this amino acid sequence was relevant for egg interaction. Studies with Tpx-1 and anti-Tpx-1 revealed the participation of this protein in gamete fusion through binding to complementary sites in the egg. In competition studies, DE reduced binding of Tpx-1 dose-dependently, indicating that both CRISP share the egg complementary sites. That anti-DE and anti-Tpx-1 inhibit sperm-egg fusion while recognizing only the corresponding proteins, suggests functional cooperation between these homologous CRISP to ensure fertilization success. These results increase our understanding of the molecular mechanisms of gamete fusion and contribute to the development of new and safer fertility regulating methods.
Animals ; Cell Fusion ; Epididymis ; Female ; Germ Cells ; physiology ; Glycoproteins ; physiology ; Humans ; Male ; Membrane Glycoproteins ; physiology ; Ovum ; physiology ; Rats ; Sperm Capacitation ; Sperm-Ovum Interactions ; physiology ; Spermatozoa ; physiology