Proteomic analysis of seminal plasma from normal volunteers and post-vasectomy patients identifies over 2000 proteins and candidate biomarkers of the urogenital system

Seminal plasma is a fluid that originates from the testis, epididymis,prostate, and seminal vesicles, and hence, proteomic studies may identify potential markers of infertility and other diseases of the genito-urinary tract. We profiled the proteomes of pooled seminal plasma from fertile Control and post-vasectomy (PV) men. PV seminal plasma samples are void of proteins originating from the testis and the epididymis due to ligation of the vas deferens, and hence, comparative analysis of Control and PV data sets allows for identification of proteins originating from these tissues. Utilizing offline MudPIT and high-resolution mass spectrometry, we were able to identify over 2000 proteins in Control and PV pools each and over 2300 proteins all together. With semiquantitative analysis using spectral counting, we catalogued 32 proteins unique to Control, 49 at lower abundance in PV, 3 unique to PV, and 25 at higher abundance in PV. We believe that proteins unique to Control or at lower abundance in PV have their origin in the testis and the epididymis. Public databases have confirmed that many of these proteins originate from the testis and epididymis and are linked to the reproductive tract. These proteins may serve as candidate biomarkers for future studies of infertility and urogenital diseases.     

Association of prostate cancer susceptibility variant (MSMB) rs10993994 with risk of spermatogenic failure

β-Microseminoprotein (MSMB) is one of the most abundant proteins in human seminal plasma. It has been identified that MSMB increased significantly in oligoasthenoteratozoospermic patients compared with fertile controls. We hypothesized that the functional polymorphism (rs10993994) of MSMB gene could be a risk factor for spermatogenic failure. For this study, 338 patients with idiopathic oligozoospermia or azoospermia and 382 fertile controls were recruited from an infertility clinic. Semen analysis was performed by computer-assisted semen analysis system. The functional polymorphism of MSMB gene was genotyped using TaqMan method. Sixty three seminal plasma samples were used to test the expression of MSMB by enzyme-linked immunosorbent assay (ELISA). The TT genotype and T allele were associated with an increased risk of idiopathic infertility with azoospermia (TT genotype: OR, 1.75; 95% CI, 1.03–2.95; T allele: OR, 1.34; 95% CI, 1.03–1.75). However, no differences were found in risk for the TT genotype or T allele among men with oligozoospermia. In addition, idiopathic infertile males have significantly higher MSMB expression levels than fertile controls. We present the first epidemiologic evidence supporting the involvement of common genetic polymorphism in MSMB gene in spermatogenic failure. These results suggest that men carrying the variant have an increased risk of spermatogenic failure associated with male infertility. Further studies are needed to confirm the roles of the polymorphism in idiopathic azoospermia and investigate the biological mechanism of elevated MSMB expression in infertile males.     

Exploration du plasma séminal humain: approche physico-chimique

Human seminal plasma glycerylphosphorylcholine (GPC), choline, citrate, and lactate were analysed by measuring the peak area of 1H nuclear magnetic resonance spectra (1H-MRS) in patients with spermatogenic failure or and obstructive azoospermia. The peak area ratios choline/citrate as well as choline/lactate were significantly different (p<0.01) between spermatogenic failure and obstructive azoospermia groups. When the serum FSH values was normal in spermatogenic failure men and obstructive azoospermia, a significant difference, was found in the GPC/choline ratio (P<0.001). The GPC/choline ratio appears to be a very important parameter not only to differentiate between spermatogenic failure and obstructive azoospermia when the FSH values are normal but also between differents forms of spermatogenic failure men. These results demonstrate the potential use of 1H-MRS on human seminal plasma in male infertility management.     

Analysis of seminal plasma from patients with non-obstructive azoospermia and identification of candidate biomarkers of male infertility

Infertility affects approximately 15% of couples with equivalent male and female contribution. Absence of sperm in semen, referred to as azoospermia, accounts for 5-20% of male infertility cases and can result from pretesticular azoospermia, non-obstructive azoospermia (NOA), and obstructive azoospermia (OA). The current clinical methods of differentiating NOA cases from OA ones are indeterminate and often require surgical intervention for a conclusive diagnosis. We catalogued 2048 proteins in seminal plasma from men presented with NOA. Using spectral-counting, we compared the NOA proteome to our previously published proteomes of fertile control men and postvasectomy (PV) men and identified proteins at differential abundance levels among these clinical groups. To verify spectral counting ratios for candidate proteins, extracted ion current (XIC) intensities were also used to calculate abundance ratios. The Pearson correlation coefficient between spectral counting and XIC ratios for the Control-NOA and NOA-PV data sets is 0.83 and 0.80, respectively. Proteins that showed inconsistent spectral counting and XIC ratios were removed from analysis. There are 34 proteins elevated in Control relative to NOA, 18 decreased in Control relative to NOA, 59 elevated in NOA relative to PV, and 16 decreased in NOA relative to PV. Many of these proteins have expression in the testis and the epididymis and are linked to fertility. Some of these proteins may be useful as noninvasive biomarkers in discriminating NOA cases from OA.     

Immunocapture-Selected Reaction Monitoring Screening Facilitates the Development of ELISA for the Measurement of Native TEX101 in Biological Fluids

Monoclonal antibodies that bind the native conformation of proteins are indispensable reagents for the development of immunoassays, production of therapeutic antibodies and delineating protein interaction networks by affinity purification-mass spectrometry. Antibodies generated against short peptides, protein fragments, or even full length recombinant proteins may not bind the native protein form in biological fluids, thus limiting their utility. Here, we report the application of immunocapture coupled with selected reaction monitoring measurements (immunocapture-SRM), in the rapid screening of hybridoma culture supernatants for monoclonal antibodies that bind the native protein conformation. We produced mouse monoclonal antibodies, which detect in human serum or seminal plasma the native form of the human testis-expressed sequence 101 (TEX101) protein—a recently proposed biomarker of male infertility. Pairing of two monoclonal antibodies against unique TEX101 epitopes led to the development of an ELISA for the measurement of TEX101 in seminal plasma (limit of detection: 20 pg/ml) and serum (limit of detection: 40 pg/ml). Measurements of matched seminal plasma samples, obtained from men pre- and post-vasectomy, confirmed the absolute diagnostic specificity and sensitivity of TEX101 for noninvasive identification of physical obstructions in the male reproductive tract. Measurement of male and female serum samples revealed undetectable levels of TEX101 in the systemic circulation of healthy individuals. Immunocapture-SRM screening may facilitate development of monoclonal antibodies and immunoassays against native forms of challenging protein targets.Monoclonal antibodies that bind the native form of a protein are indispensable for the development of sensitive immunoassays, production of therapeutic antibodies and for studying protein interaction networks by affinity purification-mass spectrometry (1, 2). Large-scale purification of native proteins from biological samples may be challenging, so recombinant proteins or protein fragments are often used for antibody production. Antibodies produced against short peptides, protein fragments, or even full length recombinant proteins, however, may not bind the native protein conformation present in biological fluids, thus limiting the utility of antibodies. Rapid screening of antibody-producing hybridoma clones for native protein binders requires highly specific and sensitive assays, performed under nondenaturing conditions. Here, we report the capability of an immunocapture-SRM assay to facilitate fast screening of hybridoma cultures for monoclonal antibodies that recognize the native conformation of testis-expressed sequence 101 (TEX101)¹ protein in biological fluids.Recently, we discovered, verified, and validated two proteins, testis-specific protein TEX101 and epididymis-specific protein ECM1, as biomarkers for the differential diagnosis of azoospermia (3, 4). Combination of TEX101 and ECM1 proteins measured in seminal plasma could differentiate between normal spermatogenesis, obstructive azoospermia (OA), and nonobstructive azoospermia (NOA) with very high diagnostic sensitivity and specificity. TEX101 levels in seminal plasma also facilitated classification of NOA subtypes of hypospermatogenesis, maturation arrest and Sertoli cell-only syndrome (5). A clinical laboratory test for TEX101 in seminal plasma may confirm the success of vasectomy or vasovasostomy, eliminate diagnostic testicular biopsies, and predict the success of sperm cell retrieval for assisted reproduction.Human TEX101 is a membrane GPI-anchored protein encoded by the TEX101 gene, located in the 19q13.31 region of chromosome 19. According to the Human Protein Atlas, TEX101 expression is restricted to testicular tissue and male germ cells, with no evidence of expression in any other human tissue or cell type (6). Investigation of the function of mouse TEX101 demonstrated its direct role in fertilization (7–9).We initially measured TEX101 levels in seminal plasma by mass spectrometry-based selected reaction monitoring (SRM) and immuno-SRM assays, with limits of detection of 120 and 5 ng/ml, respectively (4, 5). However, because of the ultra-wide range of TEX101 concentrations in seminal plasma of infertile and healthy men (0.5 ng/ml to 50,000 ng/ml) and theoretically zero levels for some azoospermic patients, a sensitive TEX101 immunoassay is required to develop a clinical laboratory test. In addition to immunoassay, monoclonal antibodies against native TEX101 would allow investigating its interactome and revealing its functional role in spermatogenesis and male fertility. Because TEX101 may emerge as a novel biomarker of male infertility, in this work we focused on the development of an ELISA for sensitive measurement of TEX101 in seminal plasma and serum.Our initial efforts to develop a TEX101 immunoassay using commercially available polyclonal antibodies were not successful. We found that commercial antibodies recognized only the denatured form of TEX101 and were useful for immunohistochemistry and Western blots, but not for the analysis of native TEX101 in seminal plasma. Here, we describe the production of mouse monoclonal antibodies against native TEX101, screening of antibody-producing clones by the two-step immunocapture and SRM assay, development of a sensitive ELISA and measurement of TEX101 in seminal plasma and serum (Fig. 1).Open in a separate windowFig. 1.Pipeline for the production of mouse monoclonal anti-TEX101 antibodies and screening of colonies using two-step immunocapture-SRM assay. Screening included the coating of microtiter plates with sheep anti-mouse IgG antibodies, the addition of hybridoma cell supernatants, incubation with seminal plasma containing the native form of TEX101 followed by trypsin digestion and SRM analysis. Two-step immunocapture followed by SRM detection facilitated rapid screening of antibody-producing colonies and provided the following advantages: no requirement for previously developed TEX101 antibodies, small scale antibody production on 96-well plates, screening of low amounts of the newly-produced antibodies and direct selection of antibodies against the native form of TEX101. Eventually, all positive clones were expanded and a sensitive immunofluorescent assay for TEX101 was developed in seminal plasma and serum.     

Recueil chirurgical de spermatozoïdes dans un groupe de 50 patients avec un antécédent de cryptorchidie bilatérale: facteurs pronostics d’extraction

Bilateral cryptorchidism is a severe factor of male infertility. We evaluated the results of testicular sperm extraction in 50 men with nonobstructive azoospermia associated with cryptorchidism between 1995 to 2001. We evaluated clinical parameters predictive of successful sperm extraction. Serum follicle stimulating hormone (FSH) was elevated in 67% of cases and testicular volume was decreased in 70% of cases, confirming the secretory origin of the azoospermia. Serum follicle stimulating hormone (FSH), testicular volume and histological parameters were examined as predictive factors for sperm recovery. The positive sperm recovery rate was 68%. As in the population of men with nonobstructive azoospermia, the sperm recovery rate for patients with a history of orchidopexy is approximately 68% and there are currently no clinical parameters predicting successful sperm retrieval in this subpopulation of patients.     

Evaluation of superoxide dismutase activity and its impact on semen quality parameters of infertile men

The evaluation of superoxide dismutase (SOD) activity, as one of the most important antioxidative defence enzymes, in seminal plasma of patients consulting for male infertility was presented in the article. The study included also the determination of its influence on selected human semen quality parameters. The material represents semen samples obtained from 15 men, which were divided into two groups: Group I (n=10) including patients consulting for infertility and Group II (n=5) containing healthy sperm donors as a control. All of the semen samples were cryopreserved and stored in liquid nitrogen. The frozen samples were thawed at the same time and then SOD activity was determined spectrophotometrically. The analysis of the investigations results indicates a significantly lower semen SOD activity detected in oligoasthenozoospermic patients, comparing to the activity found in normospermic men. The study showed a positive correlation between SOD activity in seminal plasma and semen quality parameters--sperm concentration and overall motility, which are regarded as the most important for normal fertilizing ability of the spermatozoa. Significantly lower SOD activity in seminal plasma of infertile patients, comparing to healthy sperm donors, as well as positive correlation and beneficial impact of SOD activity on human semen quality parameters seem to confirm the observations, that decreased seminal plasma scavenger antioxidant capacity, particularly in form of low SOD activity, can be responsible for male infertility. This trial shows that SOD activity survey in seminal plasma could be a useful tool for determining sperm fertilization potential and could improve the diagnosis of male infertility.     

Immunofluorescent synaptonemal complex analysis in azoospermic men

The molecular cause of germ cell meiotic defects in azoospermic men is rarely known. During meiotic prophase I, a proteinaceous structure called the synaptonemal complex (SC) appears along the pairing axis of homologous chromosomes and meiotic recombination takes place. Newly-developed immunofluorescence techniques for SC proteins (SCP1 and SCP3) and for a DNA mismatch repair protein (MLH1) present in late recombination nodules allow simultaneous analysis of synapsis, and of meiotic recombination, during the first meiotic prophase in spermatocytes. This immunofluorescent SC analysis enables accurate meiotic prophase substaging and the identification of asynaptic pachytene spermatocytes. Spermatogenic defects were examined in azoospermic men using immunofluorescent SC and MLH1 analysis. Five males with obstructive azoospermia, 18 males with nonobstructive azoospermia and 11 control males with normal spermatogenesis were recruited for the study. In males with obstructive azoospermia, the fidelity of chromosome pairing (determined by the percentage of cells with gaps [discontinuities]/splits [unpaired chromosome regions] in the SCs, and nonexchange SCs [bivalents with 0 MLH1 foci]) was similar to those in normal males. The recombination frequencies (determined by the mean number of MLH1 foci per cell at the pachytene stage) were significantly reduced in obstructive azoospermia compared to that in controls. In men with nonobstructive azoospermia, a marked heterogeneity in spermatogenesis was found: 45% had a complete absence of meiotic cells; 5% had germ cells arrested at the zygotene stage of meiotic prophase; the rest had impaired fidelity of chromosome synapsis and significantly reduced recombination in pachytene. In addition, significantly more cells were in the leptotene and zygotene meiotic prophase stages in nonobstructive azoospermic patients, compared to controls. Defects in chromosome pairing and decreased recombination during meiotic prophase may have led to spermatogenesis arrest and contributed in part to this unexplained infertility.     

Proteomic analysis of seminal extracellular vesicle proteins involved in asthenozoospermia by iTRAQ

Asthenozoospermia is a common cause of male infertility, but in most cases its etiology is unknown. The exocytic cell vesicles called seminal extracellular vesicles in the human seminal fluid have been reported to play a pivotal role in promoting the motility of spermatozoa, and functional disorder of seminal extracellular vesicles may cause male infertility. To determine whether abnormal seminal extracellular vesicles are involved in asthenozoospermia, the differential abundance proteins between normozoospermic (NSEV) and asthenozoospermic seminal extracellular vesicles (ASEV) samples were analyzed by iTRAQ coupled with two‐dimensional liquid chromatography–tandem mass spectrometry. A total of 3,699 proteins were identified in the seminal extracellular vesicles (false discovery rate <0.01). Overall, 11 proteins were significantly upregulated (>1.2) in ASEV and 80 were significantly downregulated (<0.833). Functional bioinformatic analysis showed that these proteins with differential abundance were mainly associated with transport, metabolism, and signal pathways. The changes of OPTN, SMYD2, EIF2B2, TRPV6, ACE, PRSS8, and PPAP2A in ASEV were verified by western blot analysis, and we found that the abundance of TRPV6 markedly reduced in the seminal extracellular vesicles and ejaculated spermatozoa of asthenozoospermic patients, which indicated trpv6 was important in sperm motility. This study provides deeper insight into the involvement of seminal extracellular vesicles in asthenozoospermia and should aid the search for novel biomarkers of male infertility.     

正常和异常的人精浆中甘油-3-磷酸胆碱、总唾液酸及化学元素含量的比较研究

用酶法和过碘酸 -硫代巴比妥酸法对正常男性和异常男性患者精浆甘油 3 磷酸胆碱(GPC)、总唾液酸 (TSA)量进行了测定 .通过电感耦合等离子直读光谱仪 (ICP)测定精浆中多种化学元素的含量 .结果表明 :正常男性与异常男性患者精浆中GPC的含量有显著性差异 (P <0 0 5) ;正常男性与异常男性患者精浆中TSA的含量无显著性差异 ;正常男性与异常男性患者精浆中钙、镁、磷、硒和锌元素的含量具有显著差异 ,而正常男性与异常男性患者精浆中铝、钡、铁和铅元素的含量无显著差异 .这些结果提示精浆中GPC、钙、镁、磷、硒和锌元素的含量可能与男性不育有关 ,而精浆中TSA、铝、钡、铁和铅元素与男性不育关系还需进一步探讨 .     

Evaluation of seminal plasma HSPA2 protein as a biomarker of human spermatogenesis status

In mammals, testicular Heat shock-related 70 kDa protein 2 (HSPA2) is a chaperon strictly linked to spermatogenesis status, whereas its presence in spermatozoa ensures successful oocyte fertilization. However, there is little information on this protein in seminal plasma in infertile males. Based on our previous two independent studies, we have selected HSPA2 to evaluate this seminal plasma protein is a potential biomarker of correct spermatogenesis.Using immunoblotting and mass spectrometry (MS) we have screened human seminal plasma samples for the presence of HSPA2. Samples were obtained from individuals with normozoospermia, cryptozoospermia, non-obstructive and obstructive azoospermia.Our results showed a lack of HSPA2 in seminal plasma in all azoospermic males however, in cryptozoospermia the results were extremely diversified. Additionally, the application of 2-dimensional gel electrophoresis (2-DE) indicated the presence of additional protein isoforms suggesting possible mechanisms underlying the male infertility.Our findings suggest seminal plasma HSPA2 protein as a possible biomarker not only of spermatogenesis status, especially in cryptozoospermic males, but also as a biomarker predicting the success of reproductive treatment including assisted reproductive techniques (ART).     

Emulsion PCR-based method to detect Y chromosome microdeletions

Deletions in Y chromosome are thought to be pathologically involved in some cases of male infertility associated with azoospermia or oligozoospermia. An emulsion-based multiplex PCR method was developed for detecting Y chromosome microdeletions in infertile men and a plasma sample of pregnant women carrying a male fetus. The sensitivity of multiplex PCR in emulsion was evaluated. Conventional PCR was also carried out for comparison. A total of 13 sequence-tagged sites (STSs) distributed in the AZF region were analyzed simultaneously with this method. The SRY gene was also detected as the inner control. Results showed that Y chromosome microdeletions were found in 4 of 19 infertile patients. Also, in 1 of 63 samples collected from pregnant women, microdeletions were found in some of the detected sites. It is suggested that the emulsion PCR assay was proven to be a promising diagnostic tool and could be widely used in further clinical and academic research.     

Seminal plasma gamma-glutamyltransferase activity and fertility.

The γ-glutamyltransferase activity of human seminal plasma does not correlate with the usual laboratory indicators of fertility. Overlapping enzyme activities in euspermic samples and aspermic post-vasectomy specimens probably excludes both sperm and epididymis as the major sources of the seminal plasma enzyme.     

A Comparative Analysis of the Altered Levels of Human Seminal Plasma Constituents as Contributing Factors in Different Types of Male Infertility

(1) Background: The relationships between the biochemical and immunological components in seminal plasma and their physiological effects on male reproductive system have been underreported. In this study, we evaluated the potential of several seminal plasma biochemical and immunological markers in the pathophysiological developments of the infertile male patients. The study was designed to identify and assess different markers that may be associated with semen functions in different types of male infertility. (2) Methods: A total of 50 infertile male patients who underwent checkup for fertility assessment and 50 fertile controls were included in this study. The complete medical history of each recruited participant was reviewed. The infertile sub-groups (non-obstructive azoospermia (NOA), asthenozoospermia (AS), normozoospermic infertile (NI), and oligozoospermia (OZ)) were characterized based on sperm motility and concentration, while NI patients were included after a thorough check up of their female partners as well. We investigated each sample for 21 different analytes, enzymes, trace elements, and immunological markers to find crucial markers posing as contributing factors to a specific type of male infertility. (3) Results: The levels of 15 out of 21 markers, assayed from the seminal plasma of infertile males, were significantly altered in comparison to fertile controls (p < 0.05). For the first time, microprotein levels were also analyzed. The presence of monocytes, lymphocytes, and granulocytes was limited to semen from NOA patients, while a significant increase in the level of platelets was observed in AS. Hierarchical clustering and ROC-AUC analysis identified the three most significant markers (zinc, LDH, and TG) for the healthy control group and asthenozoospermic group (AUC, of 0.92 and 0.81, respectively). (4) Conclusions: The altered levels of biochemical and immunological markers in seminal plasma might be associated with the different male infertility profiles and could be required for the sperm metabolism and maintenance. However, a larger sample size and follow up analysis is required for establishing the hypothesized panel of markers as biomarkers at clinical stage.     

Proteomic analysis of N‐glycosylation of human seminal plasma

Seminal plasma is a mixture of secretions from several male accessory glands. The seminal plasma contains many secreted proteins which are important for sperm function and male fertility. In this study, we employed N‐linked glycosylated peptide enrichment, combined with LC–MS/MS analysis, and establish the first large scale N‐linked glycoproteome of human seminal plasma. Combined with the results of five biological replicates, a total of 720 N‐glycosylated sites on 372 proteins were identified. Analysis of variations among five individuals revealed similar compositions of N‐glycosylated proteins in seminal plasma. The N‐linked glycoproteome could help us understanding the biological functions of human seminal plasma. The data set could also be a resource for further screening of biomarkers for male diseases including cancer and infertility at the level of N‐glycosylation. For example, N‐glycosylated prostate‐specific antigen is known to be an efficient biomarker that can distinguish benign prostate hyperplasia from prostate cancer. All MS data have been deposited in the ProteomeXchange with identifier PXD000959 ( http://proteomecentral.proteomexchange.org/dataset/PXD000959 ).     

Exploration du plasma seminal humain: Nouvelle approche par la resonance magnetique nucleaire du proton (RMN-1H)

Human seminal plasma glycerylphosphorylcholine (GPC), glycerylphosphorylethanolamine (GPE), citric acid (Cit) and lactic acid (Lac) were analzed by measuring the peak area of proton nuclear magnetic resonance (NMR) spectra in four groups of patients: 21 men with secretory azoospermia; 14 men with excretory azoospermia after vasectomy; seven patients presenting with very severe oligoasthenozoospermia; and 18 normozoospermic subjects. When comparing secretory and excretory azoospermia cases with normozoospermic men, seminal plasma GPC, Cit and Lac peak areas were lower in azoospermic cases compared to normozoospermic men (16.79, 8.18 and 2.28 versus 23.38, 10.58 and 4.3. arbitrary units respectively, P <0.01). The peak area ratios Cit/Lac and GPC/lac were significantly different between normozoospermic men and either secretory or excretory azoospermic groups (P<0.01). A significant difference was also found in the GPE/GPC peak intensity ratio between secretory and excretory azoospermia cases (P<0.001). These results demonstrate that quantitative markers such as GPC, GPE, Cit and Lac may be useful in the examination of human seminal plasma by proton NMR in infertility investigations.     

Immunologically reactive albumin-like protein in human testis and seminal plasma

An immunologically reactive albumin-like protein (albumin) was localized, by an immunostaining technique, in the testis of infertile men (normal spermatogenesis, obstructive azoospermia) at the level of the Sertoli cells and in some cells of the germinal epithelium (secondary spermatocytes and early spermatids). No positive reaction was detectable in prepubertal testis. In vasectomized men, mean seminal albumin values were drastically reduced (by about 80%) in comparison to fertile controls, indicating a probable testicular origin. Mean seminal albumin values were also decreased in patients affected by azoospermia due to a seminiferous tubular lesion (about 40%) and in oligozoospermic patients (about 30%). In the same seminal samples transferrin, an index of Sertoli cell function, was also measured. Albumin and transferrin results were well correlated in the seminal plasma of each group (with the exception of vasectomized subjects), including a group of men with abnormally high concentrations of seminal transferrin. A weak correlation was found between seminal albumin and sperm count. We suggest that the presence of albumin in the human adult testis and in seminal plasma could be related to its ability to transport androgens.     

Vasectomy effect on canine seminal plasma biochemical components and their correlation with seminal parameters

Three semen samples were collected at 48 h intervals from 20 mature research dogs previously conditioned to manual semen collection. Vasectomy was performed in all dogs, and 15 days after surgery, another three ejaculates were similarly collected. The semen was evaluated, and centrifuged to obtain seminal plasma for measurement of pH, and concentrations of total proteins (TP), total chlorides (Cl), calcium (Ca), potassium (K), and sodium (Na). The seminal plasma protein profile was evaluated by SDS-PAGE; molecular weights and the integrated optical density (IOD) of each band were estimated. There was a negative correlation between K concentration and progressive motility (r = -0.49, P = 0.027), sperm vigor (r = -0.60, P = 0.0053), and plasma integrity, evaluated by both the hypo-osmotic swelling test (r = -0.50, P = 0.026) and a fluorescent stain (r = -0.45, P = 0.046). Positive correlations between Na and K pre- and post-vasectomy (r = 0.88, P < 0.001; r = 0.56, P < 0.01, respectively) were verified. There were a total of 37 bands pre-vasectomy and 35 post-vasectomy (range, 100.6-3.6 kDa). Bands B9 and B13 (42.6 and 29.2 kDa) were not present post-vasectomy. The IOD of band B3 (73.5 kDa) was higher (P = 0.03) pre-vasectomy, compared to post-vasectomy; conversely, the IODs of bands B29 and B37 (7.8 and 3.6 kDa) increased (P = 0.026 and 0.047). Pre-vasectomy, there was a positive correlation (r = 0.49, P = 0.029) between band B37 band (3.6 kDa) and the Na:K ratio. In conclusion, K appeared to be involved in sperm motility in dogs and could be a tool to evaluate sperm function. The prostate contributed several elements to canine seminal plasma. Vasectomy changed Ca concentrations and the protein profile of the seminal plasma. Further studies must be performed to clarify the function of these elements on the in vivo fertility of dogs.     

Genome-wide screening of severe male factor infertile patients using BAC-array comparative genomic hybridization (CGH)

Male factor infertility is present in up to 50% of infertile couples, making it increasingly important in their treatment. Although most research into the genetics of male infertility has focused on the Y chromosome, male factor infertility may result from other genetic factors. We utilized the whole genome array comparative genomic hybridization (CGH) to identify novel genetic candidate associated with severely impaired spermatogenesis. We enrolled 37 patients with severe male factor infertility, defined as severe nonobstructive type oligozoospermia (≤5×10(6)/ml) or azoospermia, and 10 controls. Routine cytogenetic analyses, Yq microdeletion PCR test and whole genome bacterial artificial chromosome (BAC)-array CGH were performed. Array CGH results showed no specific gains or losses related to impaired spermatogenesis other than Yq microdeletions, and there were no novel candidate genetic abnormalities in the patients with severe male infertility. However, Yq microdeletions were detected in 10 patients. Three showed a deletion in the AZFb-c region and the other 7 had deletions in the AZFc region. Although we could not identify novel genetic regions specifically associated with male infertility, whole genome array CGH analysis with higher resolution including larger numbers of patients may be able to give an opportunity for identifying new genetic markers for male infertility.