Accessory Sex Gland Secretions Research Articles

The physiological roles of the boar ejaculate

During ejaculation in the boar, sperm cohorts emitted in epididymal cauda fluid are sequentially exposed and resuspended in different mixtures of accessory sex gland secretion. This paper reviews the relevance of such unevenly composed fractions of seminal plasma (SP) in vivo on sperm transport and sperm function and how this knowledge could benefit boar semen processing for artificial insemination (Al). The firstly ejaculated spermatozoa (first 10 ml of the sperm-rich fraction, SRF [Pl]) remain mainly exposed to epididymal cauda fluid and its specific proteins i.e. various lipocalins, including the fertility-related prostaglandin D synthase; than to prostatic and initial vesicular gland secretions. Plspermatozoa are hence exposed to less bicarbonate, zinc or fructose and mainly to PSP-I spermadhesin; than if they were in the rest of the SRF and the post-SRF (P2). Since the Pl-SP is less destabilizing for sperm membrane and chromatin, Pl-spermatozoa sustain most in vitro procedures, including cryopreservation, the best. Moreover, ejaculated firstly, the Pl-spermatozoa seem also those deposited by the boar as a vanguard cohort, thus becoming overrepresented in the oviductal sperm reservoir (SR). This vanguard SR-entry occurs before the endometrial signalling of SP components (as PSP-I/PSP-11 and cytokines) causes a massive influx of the innate defensive PMNs to cleanse the uterus from eventual pathogens, superfluous spermatozoa and the allogeneic SP. The SP also conditions the mucosal immunity of the female genital tract, to tolerate the SR-spermatozoa and the semi-allogeneic conceptus. These in vivo gathered data can be extrapolated into procedures for handling boar spermatozoa in vitro for Al and other biotechnologies, including simplified cryopreservation.

Untargeted metabolomic profiling of accessory sex gland fluid from Morada Nova rams.

The present study was conducted to characterize the metabolome of accessory gland fluid (AGF) of locally adapted Morada Nova rams, raised in the Brazilian Northeast. AGF was collected by an artificial vagina from five vasectomized rams. Metabolites were identified by gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography-mass spectrometry (LC/MS), with the support of Human Metabolome Database, PubChem, LIPID Metabolites, Pathways Strategy databases, and MetaboAnalyst platforms. There were 182 and 190 metabolites detected by GC/MS and LC/MS, respectively, with an overlap of one molecule. Lipids and lipid-like molecules were the most abundant class of metabolites in the ram AGF (127 compounds), followed by amino acids, peptides, and analogs(103 metabolites). Considering all GC/MS and LC/MS, fructose, glycerol, citric acid, d-mannitol, d-glucose, and l-(+)-lactic acid were the most abundant single metabolites present in the ram AGF. Meaningful pathways associated with AGF metabolites included glycine, serine and threonine metabolism; pantothenate and CoA biosynthesis; galactose metabolism; glutamate metabolism and phenylalanine metabolism, and so forth. In conclusion, the combined use of LC/MS and GC/MS was essential for getting a holistic view of the compounds embedded in the ram AGF. Chemical analysis of the accessory sex gland secretion is relevant for understanding sperm function and fertilization.

Improved sperm motility after 4 h of ejaculatory abstinence: role of accessory sex gland secretions.

Various studies have sought to determine the typical v. optimal abstinence period after which semen samples should be collected, with many contradictory results reported. Several factors influence the semen microenvironment, and thus sperm parameters. In this study we focused on the secretions of the prostate, seminal vesicles and the epididymis. Semen samples were obtained from healthy normozoospermic males (n=16) after 4-day and 4-h periods of ejaculatory abstinence, and standard semen analysis was performed using computer-aided sperm analysis, whereas seminal plasma citric acid, neutral α-glucosidase and fructose concentrations were measured using assay kits. There were significant decreases in total sperm count (P<0.001), sperm concentration (P<0.05) and semen volume (P<0.05) after 4h compared with 4 days ejaculatory abstinence. Furthermore, increases were observed in total sperm motility (P<0.05) and sperm progressive motility (P<0.01) after a 4-h abstinence period, accompanied by significant reductions in citric acid (P<0.05), α-glucosidase (P<0.01) and fructose (P<0.01) concentrations. In addition, due to the decreased number of spermatozoa, these concentrations translated to a significant decrease in fructose (P<0.05) per spermatozoon, indicating an intrinsic mechanism capitalising on alternative sources of energy for increased metabolic function and subsequent sperm motility.

Differences in the expression of microRNAs and their predicted gene targets between cauda epididymal and ejaculated boar sperm

Mammalian spermatozoa gradually mature and acquire fertility during the transition from the testis to the caput and cauda epididymis, after which they are stored at the tail of the epididymis and the ampulla of vas deferens. During ejaculation, mixing of spermatozoa with the secretions of accessory sex glands leads to their dilution and changes in their function. Although remarkable progress has been made toward the understanding of changes in spermatozoa biochemistry and function before and after ejaculation, it is unknown whether microRNAs (miRNAs) are involved in regulating the function of spermatozoa during the transition between the cauda epididymis and ejaculation. In this study, 48 miRNAs were selected for analysis on the basis of their potential involvement in spermatogenesis, sperm maturation, and quality parameters markers. The differential expression levels of these 48 miRNAs between the caudal epididymis and fresh ejaculates of boar spermatozoa were determined. We found that 15 miRNAs were significantly differentially expressed (eight downregulated and seven upregulated) between boar cauda epididymal and fresh spermatozoa. Five miRNAs hypothesized to be involved in sperm apoptosis were further tested to demonstrate their influence over the expression of their target mRNAs using quantitative reverse-transcription polymerase chain reaction. Together, our findings suggest that these differentially expressed miRNAs are associated with the functional regulation of spermatozoa between cauda epididymis and ejaculation.

Ejaculated Mouse Sperm Enter Cumulus-Oocyte Complexes More Efficiently In Vitro than Epididymal Sperm

The mouse is an established and popular animal model for studying reproductive biology. Epididymal mouse sperm, which lack exposure to secretions of male accessory glands and do not precisely represent ejaculated sperm for the study of sperm functions, have been almost exclusively used in studies. We compared ejaculated and epididymal sperm in an in vitro fertilization setting to examine whether ejaculated sperm enter cumulus-oocyte complexes more efficiently. In order to prepare sperm for fertilization, they were incubated under capacitating conditions. At the outset of incubation, ejaculated sperm stuck to the glass surfaces of slides and the incidences of sticking decreased with time; whereas, very few epididymal sperm stuck to glass at any time point, indicating differences in surface charge. At the end of the capacitating incubation, when sperm were added to cumulus-oocyte complexes, the form of flagellar movement differed dramatically; specifically, ejaculated sperm predominantly exhibited increased bending on one side of the flagellum (a process termed pro-hook hyperactivation), while epididymal sperm equally exhibited increased bending on one or the other side of the flagellum (pro-hook or anti-hook hyperactivation). This indicates that accessory sex gland secretions might have modified Ca2+ signaling activities in sperm, because the two forms of hyperactivation are reported to be triggered by different Ca2+ signaling patterns. Lastly, over time, more ejaculated than epididymal sperm entered the cumulus oocyte complexes. We concluded that modification of sperm by male accessory gland secretions affects the behavior of ejaculated sperm, possibly providing them with an advantage over epididymal sperm for reaching the eggs in vivo.

Declining semen quality and steadying seminal plasma ions in heat-stressed boar model.

There are increasing concerns about infertility of male exposure to high environmental temperatures. Nevertheless, the relationship between heat and accessory sex gland secretion underlying the high ambient temperature-induced poor semen quality has not yet been addressed. In the present study, five boars were used as an animal model to evaluate semen quality and the secretory function of accessory sex glands. After the boars received 3 days of heat exposure, semen collection was standardized to 18 continual times with a 3-day interval to determine the semen variables of semen volume, semen concentration, abnormal spermatozoa, seminal plasma composition, and testosterone level in the seminal plasma and serum. The total sperm count was lowest by the end of week 2. The higher abnormal spermatozoa percentage were observed by the end of week 2 and persisted until week 6 after heat exposure. Additionally, there was no significant change in semen volume, testosterone level, and concentrations of ions and total protein in the seminal plasma before and after heat exposure. A single 3-day heat exposure caused poor semen quality, but did not disturb accessory sex gland secretion in boars. Declining semen quality might be mainly due to the damaged germ cells, which were sensitive to elevated temperature in hot summer months.

Cathepsin A protein from the accessory sex gland of the Chinese mitten crab (Eriocheir sinensis) plays a key role in spermatophore digestion

Accessory sex gland (ASG) secretory proteins of the Chinese mitten crab (Eriocheir sinensis) can effectively digest the spermatophore wall. In order to identify which proteins participate in spermatophore wall digestion, a 50-kDa protein secreted from the ASG was purified to homogeneity by a series of isolation steps, including ammonium sulfate fractionation, Sephadex G-25 S gel-filtration, ion exchange chromatography on a DEAE-Sephacel column and Sephacryl S-200 gel-filtration. The purified protein was effective in spermatophore wall rupture, and the subsequent HPLC–ESI-MS/MS shotgun analysis showed the digestive protein to be cathepsin A (cathA). This finding was also confirmed by Western blot analysis and a cathA inhibitor digestion experiment. ELISA analysis showed that cathA enzymatic activity from ASG secretions increased during its purification process. Furthermore, enzymatic activity was significantly higher in the mating period of E. sinensis parallel to the latest developmental stage of the gland. Moreover, analysis from a cathA inhibitor that inhibits spermatophore wall digestion showed that cathA is the main enzyme involved. Hence, we first report the characterization of cathA from the ASG, which might play a key role in digesting the spermatophore wall of E. sinensis.

Heparin and Heparin Binding Proteins: Potential Relevance to Reproductive Physiology

Glycosaminoglycans (GAGs) have crucial roles in cell-cell interaction and communication. The communication between sperm and egg during fertilization is the finest example of intercellular communication involving a protein-carbohydrate recognition system. GAGs, especially heparin, are implicated in various processes, such as capacitation, acrosome reaction (AR), and sperm nuclei decondensation by interacting with a wide range of proteins, leading to fertilization. Seminal plasma (SP) comprises of multiple proteins that bind to heparin and related GAGs. Heparin binding proteins (HBPs) originating from secretions of the male accessory sex glands are known to play a vital role during fertilization events. They interact with GAGs present in the female genital tract and enhance the subsequent zona pellucida-induced AR, and thus have been correlated with fertility in some species. Several carbohydrate and zona pellucida-binding proteins, many of which belong to the spermadhesin family, are identified as HBPs. Many studies have been documented about the potential physiological role of some HBPs in various steps of fertilization. However, there is insufficient knowledge about functions executed by various HBPs and their exact mechanism and pathways. An in-depth knowledge of HBPs and their role in fertilization is of fundamental importance to resolve biological pathways and protein interactions at the molecular level. This review surveys some of the relevant findings supporting the potential role of heparin and HBPs in reproduction. It also describes consensus heparin binding sites emerging from known literature on HBPs that interact with heparin.

Effects of sperm DNA damage on the levels of RAD51 and p53 proteins in zygotes and 2-cell embryos sired by golden hamsters without the major accessory sex glands

We previously reported that the male accessory sex gland (ASG) secretion is the main source of antioxidants to safeguard sperm genomic integrity and functional competence. Removal of all ASGs in the golden hamster can reduce male fertility by increasing embryo wastage. This study aims to investigate whether the oxidative DNA-damaged sperm from hamsters without all ASGs (TX) could successfully fertilize oocytes and to qualify the status of DNA repair by the expression of RAD51 and p53 proteins. Here we demonstrated a significantly higher DNA-base adduct formation (8-hydroxy-2′-deoxyguanosine) in sperm from TX males than those from sham-operated males. Comet assays demonstrated that all female pronuclei in both zygotes were intact, but single- and double-strand DNA damage was found in decondensed sperm in TX males only. DNA damage could also be detected in both nuclei of the TX 2-cell embryos. RAD51, a DNA repair enzyme, was found to be evenly distributed in the cytoplasm and nuclei in oocytes/zygotes, while at the 2-cell stage, a strong expression of p53 protein and a larger clear perinuclear area without RAD51 expression were found in TX embryos. In conclusion, we demonstrated for the first time DNA damage in decondensed sperm of zygotes and blastomeres of 2-cell stage embryos sired by TX males, resulting in the activation of DNA repair. Sperm DNA damage could induce the increase in p53 expression and the reduction of RAD51 expression in the TX 2-cell stage embryos.

Isolation and characterization of zinc-binding proteins of canine seminal plasma

Zinc-binding proteins from seminal plasma (ZnBPs) originate in the secretions of different accessory sex glands and are implicated in key events associated with sperm-egg fertilization processes. This study describes the isolation and characterization of the ZnBPs of canine seminal plasma. Ejaculates were collected from three crossbred dogs for a 2-week period. The ZnBPs as well as non zinc-binding proteins (nZnBPs) were isolated by zinc-dependent affinity chromatography. The isolated fractions were subjected to native gel electrophoresis (one-dimensional polyacryamide gel electrophoresis, PAGE) and sodium dodecyl sulphate polyacryamide gel electrophoresis (SDS-PAGE), using denaturing and reducing conditions. Zinc-elution profile using affinity chromatography displayed two protein fractions represented by the nZnBPs and ZnBPs, respectively. Using native gel electrophoresis, it was found that both the nZnBPs and ZnBPs occurred in their native state as aggregates, ranging from 140 to 669 kDa. The nZnBPs were disaggregated into 8 protein bands, with molecular weights ranging from 10.7 to 79.7 kDa, following SDS-PAGE analysis. By contrast, SDS-PAGE analysis of the ZnBPs revealed 13 protein bands, with molecular weights ranging from 11.6 to 152.3 kDa. Densitometric analysis showed that 46-48% of nZnBPs could be accounted by protein fractions with molecular weights of 10.7 and 14.2 kDa. Also, 2 protein fractions with molecular weights of 11.6 and 14.3 kDa, were predominant in ZnBPs, accounting for approximately 28-30% of the total proteins. These results demonstrate the zinc-binding capacity of proteins secreted by the canine prostate. The findings of this study indicate that ZnBPs of canine seminal plasma comprise several protein fractions, which might be implicated in the reproductive processes in the dog.

The Vanguard Sperm Cohort of the Boar Ejaculate is Overrepresented in the Tubal Sperm Reservoir In Vivo

In boars, sperm cohorts are sequentially emitted in epididymal cauda fluid and resuspended in different mixtures of accessory sex gland secretions while ejaculated in various fractions. During natural mating, these ejaculate fractions sequentially enter the cervix-uterine lumen, are quickly transported towards the tips of the uterine horns and colonize the oviductal sperm reservoirs (SR). Using a simple experiment, we tested the hypothesis that the first ejaculated sperm subpopulation (fortuitously present in the peak portion of the sperm-rich fraction [SRF], the so-called Portion 1, P1) is, by reaching first the SR, overrepresented there. Spermatozoa from P1- and of P2- (last portion of the SRF and the Post-SRF) were collected from 3 fertile boars. P1-spermatozoa were fluorophore DNA-stained, while P2-spermatozoa were kept unstained. Weaned estrous sows were conventionally inseminated (12 h after onset of estrus) with similar sperm numbers (approx 10 x 10(9) spermatozoa) per portion but in different orders as follows: (i) a mix of P1 and P2 aliquots (control, P1+P2, n=5), or testing (ii) a sequential order (P1-P2, Treatment A, n=5) or (iii) an inverse order (P2-P1, Treatment B, n=5) of cohort AI. Sows were euthanized approx 3 h post-AI, and the SRs were flushed to recover the spermatozoa, which were accounted for as stained or unstained. The total number of spermatozoa flushed did not differ between groups or boars (NS, ranging 0.9 to 2.0 x 10(9)). Sequential, in vivo-like, sperm deposition (P1-P2, Treatment A) yielded the highest proportion of stained P1-spermatozoa in the SRs (59.8 +/- 5.66%, means +/- SEM) compared with when the order was reversed (P2-P1, Treatment B; 15.6 +/- 2.1% P1-spermatozoa, P<0.05) or P1 and P2 sperm suspensions were mixed (control, 36.9 +/- 2.70% P1-spermatozoa, P<0.05). The tested hypothesis proved valid; if inseminated in the same order as ejaculated in vivo, P1-spermatozoa become overrepresented in the SR. The physiological consequences of this skewed SR-colonization are discussed in this paper alongside the advantageous use of P1-spermatozoa for handling, including cryopreservation.

Evaluation of ascorbate and urate antioxidant capacity in human semen.

The ascorbate/urate ratio in the seminal plasma was studied in 76 randomly chosen infertile men. The levels of ascorbate and urate were found to vary widely (range: 93-954 mumol l-1 and 127-670 mumol l-1, respectively), while the ascorbate/urate ratio was 1.03 +/- 0.63 (mean +/- SD), indicating almost equimolar concentrations of both compounds in more than 60% of the subjects investigated. No relationship of ascorbate with any biochemical marker of accessory sex gland secretions was observed, whereas an inverse correlation of urate with some prostatic markers, acid phosphatase (-0.37; P < 0.001), zinc (-0.35; P < 0.002) and citric acid (-0.33; P < 0.003), was found. In vitro experiments were conducted on an artificial suspension containing ascorbate and urate at physiological levels and activated polymorphonuclear leukocytes in the normal range (as proposed by WHO) to determine the extent to which the presence of superoxide anion-generating leukocytes contribute to the depletion of ascorbate and urate. The ascorbate level did not change in the presence of 0.2 x 10(6) leukocytes ml-1, while higher amounts of activated polymorphonuclear leukocytes initiated ascorbate oxidation, the intensity of which was in correlation with the extent of leukocyte contamination. After incubation (37 degrees C, 30 min) in the presence of 0.4, 1.0 and 1.5 x 10(6) cells ml-1, the average decline from the initial ascorbic acid level was 24, 43 and 49%, respectively. However, exposure of whole semen, instead of buffer, to oxidants released from the same amount of activated polymorphonuclears led to only 2.6, 11 and 22% decrease of the ascorbic acid, most probably due to the action of other superoxide anion scavenger compounds present in semen. Excessive superoxide anion production due to the presence of activated leukocytes had no influence on urate level either in the artificial suspension or in semen. The ability of ascorbate to afford protection against leukocyte-associated superoxide anions is not hampered in the semen of infertile men, provided that leukocyte contamination does not exceed 1 x 10(6) cells ml-1. The possible role of urate in stabilizing the ascorbate antioxidant activity in seminal plasma should be further investigated.

Absence of paternal accessory sex gland secretions disturbs epigenetic reprogramming and expression of Igf2 and Dlk1 in golden hamster embryos

Accessory sex gland (ASG) secretion is known to exert an effect on sperm that is heritable in hamster embryos. We hypothesized that ASG secretion changes the sperm epigenome, which in turn is propagated in sired embryos. To test our hypothesis, we produced male hamsters that were devoid of either all ASG (TX) or only the ventral lobe of the prostate gland (VPX). A sham-operated control group (SH) was also established. These males were mated with normal females; uterine sperm, fertilized oocytes, and pre-implantation embryos were harvested from the females after mating. Epididymal sperm were collected at the end of experiments. Immunofluorescent staining was performed on these harvested specimens using antibodies against 5-methylcytosine, Dnmt1, Dnmt3a, Dnmt3b, protamine 1, protamine 2, and aectyl-H4K5. Expression of Igf2 and Dlk1 were analyzed by real-time RT PCR and in situ hybridization. We demonstrated that the DNA methylation pattern changed dynamically in SH, TX, and VPX fertilized oocytes. In VPX and TX embryos, DNA demethylation was slower and remethylation was delayed when compared with SH embryos. In addition, Dnmt3b expression was also abnormal. When sperm from VPX and TX males were exposed to whole ASG secretion in vivo, the resulting embryos all methylated normally. Immunofluorescent staining revealed that there was no difference in protamine packaging of uterine sperm from VPX and TX males. The staining also showed a lower level of acetyl-H4K5 expression in the male pronuclei of TX produced embryos. Furthermore, the VPX and TX embryos also expressed higher levels Igf2, and Dlk1. We concluded that interactions between ASG and sperm affected: (1) histone acetylation in male pronuclei; (2) DNA methylation in fertilized oocytes; and (3) Igf2 and Dlk1 expression embryos.

A Lack of Contact of Sperm with Accessory Sex Gland Secretions Deregulates DNA Methylation and Imprinted Gene Expression in Rodent Embryos

Increased oxidative DNA damage is observed in sperm devoid of contact with accessory sex gland (ASG) secretion. After fertilization, these sperm may produce abnormal embryos. In this study, we investigated the possibility that the pattern of DNA methylation and imprinted gene expression in these embryos may be perturbed. Epididymal sperm, uterine sperm, and embryonic day 13 (E13) embryos were collected from hamster and mouse. The extent of global DNA methylation was determined with an antibody against methylcytosine using an embryo DNA dot. The sperm and embryo Gtl2 promoter and H19 differential methylated region (DMR) were subject to bisulfite sequencing. Expression of their reciprocally activated genes Dlk1 and Igf2 was quantified by real-time PCR. Genome-wide DNA hypo-methylation in both hamster and mouse embryos sired by males without ASG was observed. The imprinting pattern of fetal mouse Gtl2 promoter and fetal hamster H19 DMR were also disrupted while the expression of Dlk1 and Igf2 was dysregulated in the hamster embryo. This study suggests that a lack of contact of sperm with the ASG secretion disrupts genome-wide DNA methylation and also affects the DNA methylation pattern of imprinted genes in embryos.

Identification of proteins from the accessory sex gland of Eriocheir sinensis by two-dimensional electrophoresis and mass spectrometry

Accessory sex glands play an important role in male reproduction; however, the function of their secretions has not been completely elucidated. This study investigated the function of the accessory sex glands of the crustacean, Eriocheir sinensis, by identifying proteins secreted during early and peak developmental periods using two-dimensional electrophoresis and mass spectrometry. Most of the proteins had a low molecular weight and were concentrated in the region of pI 4–7 on the gel. After digestion, 13 differentially expressed proteins were analyzed by mass spectrometry. Among these 13, nine were preliminarily identified and could be categorized into four functional groups: spermatozoa capacitation, anti-oxidant, metabolism, and transcription and post-transcriptional regulation. The characteristics of these proteins confirmed that accessory sex gland secretions play an important role in the physiological status of sperm. This proteomics analysis of accessory sex gland can form the foundation for further studies of the function of accessory sex gland secretions.

Localization and characterization of glutathione peroxidase (GPx) in boar accessory sex glands, seminal plasma, and spermatozoa and activity of GPx in boar semen

Boar ejaculate owes its characteristic large volume mainly to accessory sex gland (ASG) secretions. These are main contributors to the protective functions of seminal plasma, especially against oxidative damage. Numerous antioxidants have been detected in ASG secretions, and, respectively, in seminal plasma. However, as regards one key antioxidant protector -- the Se-dependent enzyme glutathione peroxidase (GPx) -- there is no agreement yet among researchers as to its presence in boar seminal plasma. Nevertheless, the beneficial effect of dietary Se supplementation on male fertility has been widely recognized. The aim of the present study was to investigate the localization and characterization of GPx in boar ASGs, seminal plasma, and spermatozoa, as well as to evaluate GPx activity in boar semen. Immunohistochemical assays demonstrated GPx presence in the epithelial cells, vacuole membranes, and vascular endothelium of boar seminal vesicle, prostate and bulbourethral glands. Western blot analysis demonstrated the presence of a monomer form of GPx with MW 20 kDa in lysates from seminal vesicle, prostate, bulbourethral glands, and spermatozoa, but not in seminal plasma. Surprisingly, peroxidase activity detected in seminal plasma from normal ejaculates was nearly three times as high as in spermatozoa. Our findings confirmed the presence of immunoreactive GPx in the boar reproductive tract, while further investigation is still warranted to uncover the exact protein forms involved and their function.

A comprehensive proteomic analysis of the accessory sex gland fluid from mature Holstein bulls

The expression of proteins in accessory sex gland fluid (AGF) of proven, high use mature Holstein bulls was evaluated. Thirty-seven bulls with documented fertility based on their non-return rates were studied. AGF was obtained by artificial vagina after bulls were surgically equipped with cannulae in the vasa deferentia. Samples of AGF were evaluated by two-dimensional SDS-PAGE, gels stained with Coomassie blue and polypeptide maps analyzed by PDQuest software. A master gel generated by the software representing the best pattern of spots in the AGF polypeptide maps was used as a reference for protein identification. Proteins were identified by Western blots and capillary liquid chromatography–nanoelectrospray ionization tandem-mass spectrometry (CapLC–MS/MS). The product ion spectra were processed using Protein Lynx Global Server 2.1 prior to database search with both PLGS and MASCOT (Matrix Science) software. The entire NCBI database was considered for mass fingerprint matching. An average of 52 ± 5 spots was detected in the AGF 2D gels, which corresponded to proteins potentially involved in capacitation (bovine seminal plasma protein—BSP-A1/A2 and A3, BSP 30 kDa, albumin); sperm membrane protection, prevention of oxidative stress, complement-mediated sperm destruction and anti-microbial activity (albumin, clusterin, acidic seminal fluid protein—aSFP, 5′-nucleotidase—5′-NT, phospholipase A 2—PLA 2); acrosome reaction and sperm-oocyte interaction (PLA 2, osteopontin); interaction with the extracellular matrix (tissue inhibitor of metalloproteinase 2, clusterin) and sperm motility (aSFP, spermadhesin Z13, 5′-NT). The 20 spots distinguished in all gels were matched to proteins associated with these functions. Proteins identified by tandem mass spectrometry as ecto-ADP-ribosyltransferase 5 and nucleobindin, never described before in the accessory sex gland secretions, were also detected. In summary, we identified a diverse range of components in the accessory sex gland fluid of a select group of Holstein bulls with documented fertility. Known characteristics of these proteins suggest that they play important roles in sperm physiology after ejaculation.

Sperm Ion Channels: Molecular Targets for the Next Generation of Contraceptive Medicines?

Sperm Ion Channels: Molecular Targets for the Next Generation of Contraceptive Medicines?

Effects of exposing boars to different artificial light regimens on semen plasma markers and “in vivo” fertilizing capacity

This study was designed to assess the effects of exposing boars to an artificial photoperiod on semen quality in terms of sperm concentration, sperm vitality, sperm motility and acrosome integrity. We also determined biochemical semen plasma variables, such as total protein concentration, phosphorylated tyrosine residues and fructose, glucose and sorbitol contents, along with their effects on the fertility, prolificacy and libido of the boars. Three groups of 10 males were kept for 3 months under experimental conditions of 24, 12 and 0 h of artificial light, and a constant temperature of 21 ± 1 °C and 60–75% humidity. The animals were fed a nutritious diet and subjected to semen collection twice per week. Semen samples were analyzed throughout the entire experimental period. Our results indicate that, while the extreme photoperiods (0 and 24 h of light) affected semen quality in terms of sperm concentration, acrosome integrity and semen volume, its fertilizing capacity was only significantly reduced under conditions of absolute darkness. Sperm motility was found to be a poor indicator of fertilizing ability, while other sperm factors, such as acrosome integrity or other functional variables seemed to behave better. The photoperiod was found to affect the production of accessory sex gland secretions more than their composition. In addition, light effects on fertility, prolificacy and libido seemed to be achieved through independent mechanisms.

Duration of sexual abstinence: epididymal and accessory sex gland secretions and their relationship to sperm motility

The data on the association between the abstinence period and sperm motility are conflicting. Ejaculates from 422 men assessed for infertility were analysed according to the World Health Organization (WHO) guidelines. Seminal plasma neutral alpha-glucosidase (NAG), prostate-specific antigen (PSA), zinc and fructose were measured. Three groups were defined according to the length of sexual abstinence: G2-3 (2-3 days), G4-5 (4-5 days) and G6-7 (6-7 days). The total percentage of progressively motile spermatozoa was significantly higher in G4-5 compared with G2-3 and G6-7 (medians 55 versus 47 and 42%; P=0.039 and P <0.001, respectively). The percentage of spermatozoa with tail defects was significantly higher in G6-7 compared with G2-3 and G4-5 (medians 14 versus 10 and 10%; P=0.011 and P=0.002, respectively). NAG was significantly lower in G2-3 compared with G4-5 and G6-7 (medians 23 versus 34 and 34 mU/ejaculate; P <0.001 and P=0.001, respectively). The same trend was found regarding zinc (medians 6 versus 8 and 8 mumol/ejaculate; P=0.001 and P=0.005, respectively). Within the time interval recommended by the WHO (2-7 days), the length of the abstinence period is associated with sperm characteristics and should be taken into consideration when interpreting results of semen analysis.