Effects of chelating calcium in cryopreservation extender on frozen-thawed dog semen / [Efeitos da quelação de cálcio no meio de criopreservação no sêmen descongelado de cão]

We evaluated the effect of reducing free calcium in the cryopreservation medium, using the calcium chelator ethylene diamine tetracetic acid (EDTA) at 0.3% and 0.5% concentrations. Three male mixed breed dogs were subjected to semen collection by digital manipulation (n=16). Each ejaculate was divided in three aliquots, and each one was diluted in TRIS-glucose-egg yolk extender with 6% glycerol and 0.5% Equex STM Paste® (TGE, control); and added with 0.3% EDTA (EDTA 0.3) or 0.5% EDTA (EDTA 0.5). Calcium concentration reduced in EDTA 0.3 and all the calcium ions were chelated in EDTA 0.5. The EDTA addition did not affect sperm morphology or plasma membrane integrity; however, by removing all free calcium (EDTA 0.5), the sperm motility reduced (64.7% in TGE and 45% in EDTA 0.5; p<0.05). Acrosome integrity and sperm binding ability were not improved by calcium chelation. The failure to prevent the premature AR may explain why sperm longevity was not affected by calcium removal. Thus, the partial or complete calcium removal, through EDTA addition, is not able to prevent acrosomal damage or premature acrosomal reaction, and therefore does not improve the dog sperm binding ability.(AU)

Avaliou-se o efeito da redução do cálcio livre no meio de congelamento, usando-se o quelante de cálcio etilenodiaminotetracético (EDTA) a 0,3% e 0,5%. Três cães machos sem raça definida foram submetidos à coleta de sêmen por manipulação digital (n=16). Cada ejaculado foi diluído em diluidor controle com TRIS-glicose - gema de ovo (TGE, controle), ou em diluidor TGE enriquecido com 0,3% (EDTA 0,3) ou 0,5% de EDTA (EDTA 0,5). A concentração de cálcio reduziu no meio EDTA 0,3, e todos os íons de cálcio foram quelados no meio EDTA 0,5. A adição do EDTA e a consequente quelação do cálcio não afetaram a morfologia espermática ou a integridade da membrana plasmática, no entanto, ao remover todo o cálcio do meio (EDTA 0,5), a motilidade espermática se reduziu (64,7% no TGE e 45% no EDTA 0,5; P<0,05). A integridade do acrossoma e a capacidade de ligação do espermatozoide não melhoraram com a quelação do cálcio. Apesar da influência da concentração de cálcio sobre a motilidade espermática após o descongelamento, a falha em prever a reação acrossomal prematura pode explicar por que a longevidade espermática não foi afetada pela remoção do cálcio no meio. Dessa forma, a remoção parcial ou total do cálcio, por meio da adição de EDTA, não é capaz de prevenir o dano no acrossoma ou a reação acrossomal prematura e, portanto, não aumenta a capacidade do espermatozoide de se ligar ao oócito.(AU)

Endocannabinoid Signaling in Spermatozoa: A Mini-Review

Spermatozoa undergoes array of signaling and intracellular pathways and ultimately become competent enough to accomplish fertilization. Hormones, ion channels and signaling molecules in both male and female reproductive tract show bidirectional cross play. The recent discovery of endocannabinoids and their receptors in male and female reproductive system opened new vistas for their research in regulating sperm function. Interestingly, endocannabinoids regulate sperm motility, capacitation, hyperactivity and eventually acrosome reaction. However, their complex intracellular pathways are still to be understood in regulating spermatozoa function. The present review highlights the major breakthrough research in the area of endocannabinoids in male reproduction and in more specific in sperm cells, and their association with regulation of sperm fertilizing competence

Participation of the inositol 1,4,5-trisphosphate-gated calcium channel in the zona pellucida- and progesterone-induced acrosome reaction and calcium influx in human spermatozoa / 亚洲男科学杂志(英文版)

The acrosome reaction is a prerequisite for fertilization, and its signaling pathway has been investigated for decades. Regardless of the type of inducers present, the acrosome reaction is ultimately mediated by the elevation of cytosolic calcium. Inositol 1,4,5-trisphosphate-gated calcium channels are important components of the acrosome reaction signaling pathway and have been confirmed by several researchers. In this study, we used a novel permeabilization tool BioPORTER® and first demonstrated its effectiveness in spermatozoa. The inositol 1,4,5-trisphosphate type-1 receptor antibody was introduced into spermatozoa by BioPORTER® and significantly reduced the calcium influx and acrosome reaction induced by progesterone, solubilized zona pellucida, and the calcium ionophore A23187. This finding indicates that the inositol 1,4,5-trisphosphate type-1 receptor antibody is a valid inositol 1,4,5-trisphosphate receptor inhibitor and provides evidence of inositol 1,4,5-trisphosphate-gated calcium channel involvement in the acrosome reaction in human spermatozoa. Moreover, we demonstrated that the transfer of 1,4,5-trisphosphate into spermatozoa induced acrosome reactions, which provides more reliable evidence for this process. In addition, by treating the spermatozoa with inositol 1,4,5-trisphosphate/BioPORTER® in the presence or absence of calcium in the culture medium, we showed that the opening of inositol 1,4,5-trisphosphate-gated calcium channels led to extracellular calcium influx. This particular extracellular calcium influx may be the major process of the final step of the acrosome reaction signaling pathway.

Influence of in vitro capacitation time on structural and functional human sperm parameters / 亚洲男科学杂志(英文版)

A cascade of dramatic physiological events is linked to the sperm acrosome reaction and binding to the oocyte's zona pellucida during human sperm capacitation. However, structural and functional sperm changes during capacitation currently remain poorly defined. Here, we performed a multibiomarker approach based on the utilization of sperm concentration, motility, viability, morphology, acrosome reaction, tyrosine phosphorylation, DNA fragmentation, and lectin-binding sites to analyze the impact caused by swim-up selection times (uncapacitated, 1 h capacitated, and 4 h capacitated) on sperm function and structure in normozoospermic samples. We found that a 4 h swim-up capacitation increased sperm quality, because a large number of cells with normal morphology and lower DNA fragmentation rates were recovered. Furthermore, the long-term capacitation induced a higher percentage of cells with tyrosine phosphorylation of the principal piece as well as a redistribution of lectin-binding sites. Overall, the multivariate biomarkers analyzed showed a less variable distribution on spermatozoa recovered after 4 h capacitation than that with the shorter capacitation time. These findings stress the importance of capacitation time as a relevant factor in sperm quality with potential biological reproductive implications both for basic research and in assisted reproduction techniques.

Role of C-type natriuretic peptide in the function of normal human sperm / 亚洲男科学杂志(英文版)

C-type natriuretic peptide (CNP) is a newly discovered type of local regulatory factor that mediates its biological effects through the specic, membrane-bound natriuretic peptide receptor-B (NPR-B). Recent studies have established that CNP is closely related to male reproductive function. The aims of this study were to determine the distribution of CNP/NPR-B in human ejaculated spermatozoa through different methods (such as immunolocalization, real time polymerase chain reaction and Western Blot), and then to evaluate the influence of CNP on sperm function i n vitro, such as motility and acrosome reaction. Human semen samples were collected from consenting donors who met the criteria of the World Health Organization for normozoospermia. Our results show that the specic receptor NPR-B of CNP is localized in the acrosomal region of the head and the membrane of the front-end tail of the sperm, and there is no signal of CNP in human sperm. Compared with the control, CNP can induce a signicant dose-dependent increase in spermatozoa motility and acrosome reaction. In summary, CNP/NPR-B can affect sperm motility and acrosome reaction, thus regulating the reproductive function of males. CNP may be a new key factor in regulating sperm function.

Efecto de la vitrificación de ovocitos humanos sobre la capacidad de unión y el estado acrosomal de espermatozoides humanos / Effect of the vitrification of human oocytes on the binding capacity and acrosome status of human sperm

Conocer los aspectos moleculares que acontecen en el proceso de unión de los espermatozoides humanos a la zona pelúcida (ZP) humana es uno de los grandes retos de la biología de la Reproducción. Por otra parte conocer si el proceso de fecundación puede verse afectado por la criopreservación de los gametos femeninos sigue siendo otra cuestión debatida en la literatura. En base a esto, el objetivo principal de este trabajo fue conocer si la vitrificación ovocitaria puede alterar la interacción de los espermatozoides con el glicocáliz de la ZP y demostrar si la ZP de estos ovocitos pierde la capacidad de inducir la reacción acrosómica en los espermatozoides. Según nuestros resultados el método de vitrificación ovocitaria cerrado (S3) no altera la capacidad de unión de los espermatozoides a la zona pelúcida, ni la capacidad de ésta para inducir la reacción acrosómica.

To know the molecular aspects that occur in the process of human sperm binding to the human zona pellucida (ZP) is one of the great challenges of reproduction biology. Moreover knowing if the fertilization process may be affected by cryopreservation of female gametes is still another issue discussed in the literature. Based on this, the main objective of this study was to determine whether the oocyte vitrification may alter the interaction of sperm with the glycocalyx of ZP and show whether these oocytes lost the ability to induce the acrosome reaction in sperm. According to our results the oocyte closed vitrification method (S3) does not alter the ability of the sperm binding to the zona pellucida, and their ability to induce the acrosome reaction.

Effects of different concentrations of parecoxib sodium on rat sperm motility, capacitation and acrosome reaction in vitro / 中华麻醉学杂志

Objective To evaluate the effects of different concentrations of parecoxib sodium on the rat sperm motility,capacitation and acrosome reaction in vitro.Methods The sperm samples from Sprague-Dawley rat epididymis were collected by Klinefelter diffusion method and randomly divided into 4 groups (n =18 each) using a random number table:control group (group C),and parecoxib sodium 100,500,1 000 μmol/L groups (P1-3 groups).Parecoxib sodium with the final concentrations of 100,500 and 1 000 μmol/L was added to the culture medium.The samples were then incubated for 5 h in an airtight container filled with 5 ％ CO2 at 37 ℃.Then sperm motility was examined in vitro at 37 ℃ and analyzed by the computer-assisted sperm analysis,including the sperm motility ((a + b)％),average path velocity (VAP),straight line velocity (VSL),curvilinear velocity (VCL) and amplitude of lateral head displacement (ALH).The capacitation effect was assessed by using the chlortetracycline staining and phase-contract microscopy.The acrosome reaction was evaluated by coomassie brilliant blue staining.Results The VAP,VSL,VCL and capacitation ability of the sperm were gradually decreased in C and P1-3 groups (P ＜ 0.05).Compared with group C,(a + b)％ in P2,3 groups and ALH in P2 group were significantly decreased (P ＜ 0.05).There was no significant difference in the acrosome reaction between groups (P ＞ 0.05).Conclusion Parecoxib sodium has significant inhibitory effects on the rat sperm motility and capacitation in a dose-dependent manner,while has no effect on the acrosome reaction in vitro.

Modulation of spermatozoon acrosome reaction

Spermatozoon acrosome reaction is an exocytotic event of the utmost importance for the development of mammalian fertilisation. Current evidence shows that the triggering of the acrosome reaction (AR) could be regulated by the action of diverse compounds, namely, metabolites, neurotransmitters and hormones. The aim of the present review is to describe the modulating effects of several compounds that have been classified as inductors or inhibitors of acrosome reaction. Among AR inductors, it is necessary to mention progesterone, angiotensin II, atrial natriuretic peptide, cathecolamines, insulin, leptin, relaxin and other hormones. Regarding the inhibitors, oestradiol and epidermal growth factor are among the substances that retard AR. It is worth mentioning that gamma-aminobutyric acid, a neurotransmitter known to be an inhibitor in the central nervous system, has been shown to induce AR. The multiple hormones located in the fluids of the female reproductive tract are also likely to act as subtle regulators of AR, constituting a fundamental aspect for the development of successful fertilisation. Finally, it is necessary to emphasise that the study of regulation exerted by hormones and other compounds on AR is essential for further understanding of mammalian reproductive biology, especially spermatozoon physiology.

Induction of the acrosome reaction test to in vitro estimate embryo production in Nelore cattle / Teste de indução da reação acrossomal na estimativa de produção in vitro de embriões Nelore

The effectiveness of induction of the acrosome reaction (AR) test as a parameter to in vitro estimate embryo production (IVP) in Nelore breed and the AR pattern by the Trypan Blue/Giemsa (TB) stain were evaluated. Frozen semen samples from ten Nelore bulls were submitted to AR induction and were also evaluated for cleavage and blastocyst rates. The treatments utilized for AR induction were: control (TALP medium), TH (TALP medium + 10μg heparin), TL (TALP medium + 100μg lysophosphatidylcholine) and THL (TALP medium + 10μg heparin + 100μg lysophosphatidylcholine). Sperm acrosomal status and viability were evaluated by TB staining at 0 and after 4h incubation at 38ºC. The results obtained for AR presented a significant difference (P<0.05) in the percentage of acrosome reacted live sperm after 4h of incubation in the treatments that received heparin. The cleavage and blastocyst rates were 60 percent and 38 percent respectively and a significant difference was observed among bulls (P<0.05). It was founded a satisfactory model to estimate the cleavage and blastocyst rates by AR induction test. Therefore, it can be concluded that the induction of the AR test is a valuable tool to predict the IVP in Nelore breed.

Avaliou-se a eficiência da técnica de indução da reação acrossomal (RA) como parâmetro para estimar a produção in vitro (PIV) de embriões Nelore e analisou-se o padrão de RA pela técnica de coloração Azul de Tripan/Giemsa (TB). Amostras de sêmen congelado de dez touros foram submetidas à indução da RA e avaliadas quanto a taxa de clivagem e blastocisto. Os tratamentos utilizados para indução da RA foram: controle (meio TALP), TH (meio TALP + 10μg heparina), TL (meio TALP + 100μg lisofosfatidilcolina) e THL (meio TALP + 10μg heparina + 100μg lisofosfatidilcolina). Avaliou-se viabilidade espermática e acrossomal pela coloração TB a zero e após 4h de incubação a 38ºC. Os resultados obtidos para RA mostram uma diferença significativa (P<0,05) na porcentagem de espermatozoides vivos com acrossoma reagindo após 4h de incubação nos tratamentos que receberam heparina. As taxas de clivagem e blastocisto obtidas foram 60 por cento e 38 por cento respectivamente e observou-se uma diferença significativa entre touros (P<0,05). Delineou-se um modelo satisfatório para estimar as taxas de clivagem e blastocisto. Desta forma, conclui-se que o teste de indução da RA é uma ferramenta valiosa para predizer a PIV na raça Nelore.

Free radicals: Their beneficial and detrimental effects on sperm function.

Free radicals are molecules with one or more unpaired electron(s) commonly found in seminal plasma. Physiologically, free radicals control sperm maturation, capacitation and hyperactivation, the acrosome reaction, and sperm-oocyte fusion. Pathologically, free radicals induce lipid peroxidation, DNA damage and apoptosis of spermatozoa. The present review deals with both the beneficial and detrimental effects of free radicals on sperm function.

Possible role of male factors in recurrent pregnancy loss.

Objective : To evaluate various causes possibly contributing towards recurrent pregnancy loss (RPL), particularly male factors. Prospective study of 75 couples with history of RPL who were investigated for genetic, anatomic, immunological, infective and systemic causes in both partners. Functional sperm capacity was assessed by the Hypo-osmotic swelling test (HOS), Acrosomal Reaction (AR), Nuclear condensationdecondensation test (NCD) and Seminal Total Leukocyte Count (TLC) along with semen analysis. Twenty male volunteers with recently proven fertility were also included for detailed sperm morphology and sperm functions test as controls. Amongst male partners 3(4%) had varicocele, 23(30.6%) had infection, 1(1.3%) immunological and 1(1.3%) had genetic abnormality. Sperm motility, viability and sperm function tests were significantly lower in the RPL group as compared to the control group (P=0.000). Male factor might be a possible contributing factor towards RPL. Both the partners should be evaluated and treated simultaneously in order to achieve desirable outcome.

Inducción de la reacción acrosómica en espermatozoides de ratón mediante solubilizados de zona pelucida de alpaca (Lama pacos L.)

La acrosina, es uno de los componentes principales del acrosoma, presenta actividad similar a la tripsina, y es liberado luego de la reacción acrosómica (RA). El objetivo del presente trabajo fue estudiar la inducción de la RA en espermatozoides de ratón con zonas pelúcidas homólogas y heterólogas. Espermatozoides de ratón capacitados por 2 horas en medio IVF suplementado con albúmina, heparina y suero sintético a 37 ºC y 5% CO2 fueron incubados en ausencia de Zona Pelucida (ZP) o en presencia de solubilizados de ZP aisladas de ratón (0,78 mg/ml) y alpaca (0,78 mg/ml y 2,35 mg/ml). La RA se evaluó mediante inmunocitoquímica con anticuerpo monoclonal anti-acrosina humana C5F10 a intervalos de 1 hora durante 4 horas. Los resultados obtenidos en espermatozoides de ratón evidencian un incremento significativo (p< 0,05) de la reacción acrosómica inducida con ZP homóloga y heteróloga.

Acrosin is one of the principal components in the acrosome, has trypsin-like activity and is secreted after the Acrosome Reaction (RA). The aim of this study was to study the induction of the acrosomal reaction in mouse sperms with homologous- Pellucid Zone and heterologous- Pellucid Zone. Mouse sperms were capacitated by two hours in IVF medium, supplemented with albumin, heparin and synthetic serum to 37 °C and 5% CO2, and before they were incubated in absence of ZP and in present of solubilized ZP from mouse (0,78 mg/ml) and alpaca (0,78 mg/ml y 2,35 mg/ml). The RA was evaluated through immunocytochemistry with monoclonal antibodies anti-human acrosin C5F10 within intervals of 1 hour during four hours. The results show a significant increase (p<0,05) in acrosome reaction induced with homologous-ZP and heterologous-ZP.

A carbohydrate-based mechanism of species recognition in sea urchin fertilization

In the present review, we describe a systematic study of the sulfated polysaccharides from marine invertebrates, which led to the discovery of a carbohydrate-based mechanism of sperm-egg recognition during sea urchin fertilization. We have described unique polymers present in these organisms, especially sulfated fucose-rich compounds found in the egg jelly coat of sea urchins. The polysaccharides have simple, linear structures consisting of repeating units of oligosaccharides. They differ among the various species of sea urchins in specific patterns of sulfation and/or position of the glycosidic linkage within their repeating units. These polysaccharides show species specificity in inducing the acrosome reaction in sea urchin sperm, providing a clear-cut example of a signal transduction event regulated by sulfated polysaccharides. This distinct carbohydrate-mediated mechanism of sperm-egg recognition coexists with the bindin-protein system. Possibly, the genes involved in the biosynthesis of these sulfated fucans did not evolve in concordance with evolutionary distance but underwent a dramatic change near the tip of the Strongylocentrotid tree. Overall, we established a direct causal link between the molecular structure of a sulfated polysaccharide and a cellular physiological event - the induction of the sperm acrosome reaction in sea urchins. Small structural changes modulate an entire system of sperm-egg recognition and species-specific fertilization in sea urchins. We demonstrated that sulfated polysaccharides - in addition to their known function in cell proliferation, development, coagulation, and viral infection - mediate fertilization, and respond to evolutionary mechanisms that lead to species diversity.

Induction of acrosome reaction by calcium ionophore A23187 in sperm separated by two-layer percoll gradient method.

The aim of this study was to compare thepercentages of sperm with an acrosome reaction between those with and without calcium ionophore A23187 induction after two-layer Percoll gradient separation. Thirty normal semen samples were obtained from the male partners of infertile couples attending the Infertility Clinic at Siriraj Hospital. After the process of sperm separation by two-layer Percoll gradient technique, the final samples samples were divided into 2 portions. An aliquot of 10 ตM of calcium ionophore A23187 was added to one portion to induce an acrosome reaction, while the other portion was used as a control. Fluorescein isothiocyanate-conjugated Pisum sativam agglutinin (FITC-PSA) staining was performed on both specimens and the acrosome reated-sperm were evaluated. The percentage of acrosome-reated sperm in the calcium ionophore A23187 induced group was significantly higher than those of the control group (24.8+6.6vs 15.4+6.0;p < 0.001). It is concluded that calcium ionophore can significantly induce an acrosome reaction on sperm separated by two-layer Percoll gradient technique, and it may be beneficial to add calcium ionophore A23187 to sperm preparation for use in IUI or IVF.

?-1,4-galactosyl transferase I induces acrosome reaction via G protein signal transduction system / 中国病理生理杂志

After the first recognition occurs between the activated sperm and zona pellucida of the oocyte from the mammalians, ?-1,4-galactosyltransferase I (? 4GalT I) combines the N-GlcNAc terminals by O-ligands on the ZP3 of the zona pellucida, which plays a difunctional role in the fertilization. The G protein signal system on the sperm membrane then is consequently activated by ZP3 via ?4GalT I, contributing to the induction of acrosome reaction. It was proved that in the activation of the G protein system, both the BBXB and BBXXB motifs on the N terminal of the long ? 4GalT I are necessary.

The Effects of Sperm Motility Stimulants on the Hyperactivation, Acrosomal Reaction of Sperm and their in vitro Fertilization / 대한산부인과학회잡지

OBJECTIVES: To evaluate the effects of sperm motility stimulants on the hyperactivation (HA), acrosomal reaction (AR) and sperm penetration assay (SPA) in fresh and frozen-thawed spermatozoa from fertile men. METHODS: We treated the semen samples obtained from 20 normospermic men (fresh semens from 10 and cryopreserved ones from 10) with pentoxiphylline (PF) and 2-deoxyadenosine (2-DXA) to evaluate the change of the patterns of motility using the computerized motility analyzer. The semen samples treated with motility stimulants were incubated in the medium with calcium ionophore A23187 for the examination of the proportion of acrosome lost spermatozoa. Finally we performed SPA in both groups for the evaluation of fertilizing capacity after stimulant treatments. RESULTS: In both fresh and cryopreserved semen samples, the addition of PF and 2-DXA significantly altered the patterns of motility (ALH, VCL, HA) known to have association with sperm quality without increasing the number of sperms with progressive motility and velocity. A23187 induced AR was also augmented by the treatment with PF and 2-DZA. Although the treatment with PF did not increase the mean rates of egg penetration significantly, in selected cases in the cryopreserved semen group, the improvement of the motility pattern was impressive. CONCLUSION: PF and 2-DXA can improve the quality of sperm function in both fresh and frozen-thawed semen from normal fertile men and may increase the sperm penetration rate of zona-free hamster eggs in selected samples of the frozen-thawed semen. The results suggest that PF and 2-DXA pretreatment can be used in the clinical practice for intrauterine insemination (IUI) program with frozen-thawed sperms as well as with samples from men with abnormal semen parameters. In addition, it may be a cost- effective therapy to try IUI combined with such a pretreatment for the couples planned to enter into the ART program.

INVESTIGATION OF RELATIONSHIP BETWEEN EXPRESSION OF MANNOSE-LIGAND RECEPTOR ON CAPACITATED HUMAN SPERM IN VITRO AND ACROSOME REACTION INDUCED BY SOLUBILIZED MOUSE ZONA PELLUCIDA / 解剖学报

Objective To study the correlation between expression of mannose-ligand receptor(MR) on capacitated human sperm in vitro and acrosome reaction induced by zona pellucida(ZP). Methods The swimming-up sperms were incubated in capacitating medium BWW for 6 hours at 37℃, and then treated with solubilized mouse zona pellucida(mZPS).After an hour, the percentages of spermatozoa labeled with FITC-DMA were counted and used to show the expression of MR; the percentages of acrosome-reacted sperm visualized with fluoresceinated Pisum sativum agglutinin(PSA) were recorded. Results There is no correlation between expression of MR on capacitated human sperm in vitro and acrosome reaction induced by mZPS.Conclusion Expression of MR on capacitated human sperm in vitro might not be the essence of capacitation.;

EFFECT OF RACEMIC (?) GOSSYPOL AND TOTAL GLYCOSIDES FROM TRIPTERYGIUM WILFORDII(GTW) ON HUMAN SPERM ACROSOME REACTION IN VITRO / 解剖学报

The effect of racemic(?) gossypol and total glycosides of tripterygium wilfordii (GTW) on human sperm acrosome reaction was observed by indirect immunofluorescence and transmission electron microscopy. The results indicate that recemic (?) gossypol and GTW may significantly inhibit human sperm acrosome reaction induced by ionophore A_(23187) at 5mg/L and 10mg/L respectively. The results of TEM shows that racemic (?) gossypol and GTW may injure the sperm plasma membrane.