The objectives were to separate canine seminal plasma proteins (with SDS-PAGE) and to determine the correlation between specific proteins and semen characteristics. Three ejaculates from 20 mixed-breed dogs, of unknown fertility, were collected by digital manipulation. Ejaculate volume and color, sperm motility, sperm vigor, percentage of morphologically normal spermatozoa, and membrane integrity (hypoosmotic swelling test and fluorescent staining) were assessed. For each dog, seminal plasma was pooled from all three ejaculates and proteins were separated with SDS-PAGE, using polyacrylamide concentrations of 13% and 22% in the separation gels. After staining, gel images were digitized to estimate molecular weights (MW) and integrated optical density (IOD) of each lane and of individual bands. Total seminal plasma protein concentration was 2.19+/-1.56 g/dL (mean+/-SD; range 1.12-5.19 g/dL). A total of 37 protein bands were identified (although no dog had all 37 bands). In the 13% gel, molecular weights ranged from 100.6 to 17.1 kDa, with four bands (49.7, 33.2, 26.4, and 19.5 kDa) present in samples from all dogs. In the 22% gel, molecular weights ranged from 15.6 to 3.6 kDa, with nine bands (15.6, 13.5, 12.7, 11.7, 10.5, 8.7, 7.8, 5.6, and 4.9 kDa) present in samples from all dogs. Combined for both gels, the majority of bands (85%) had molecular weights <17 kDa, with B20 (15.6 kDa) in high concentrations in samples from all dogs. There were positive correlations (P < or = 0.01) between two bands, B4 (67 kDa) and B5 (58.6 kDa), and sperm motility (r=0.66 and r=0.46), sperm vigor (r=0.56 and r=0.66), percentage of morphologically normal spermatozoa (r=0.55 and r=0.59), the hypoosmotic swelling test (r=0.76 and r=0.68), and fluorescent staining (r=0.56 and r=0.59), respectively. In conclusion, 37 proteins were identified in seminal plasma; two were significantly correlated with semen characteristics.

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Bovine follicular fluid (FF) constitutes the microenvironment of follicles and includes various biologically active proteins. We performed a study involving 18 healthy nonlactating Holstein cows to determine the protein expression profile of FF at key stages of follicular development. Follicles were individually aspirated in vivo at predeviation (F1 ∼ 7.0 mm), deviation (F1 ∼ 8.5 mm), postdeviation (F1 ∼ 12.0 mm), and preovulatory stages of follicle development, which were confirmed by measurement of follicular estradiol and progesterone concentrations. The FFs from nine cows were selected for proteomic analysis. After albumin depletion, triplicates of pooled FF were reduced, alkylated, and digested with trypsin. The resulting peptides were labeled with TMTsixplex and quantified using liquid chromatography-mass spectrometry/mass spectrometry. A total of 143 proteins were identified and assigned to a variety of biological processes, including response to stimulus and metabolic processes. Twenty-two differentially (P < 0.05) expressed proteins were found between stages indicating intrafollicular changes over development, with expected deviation time critical to modulate the protein expression. For instance, high concentrations of follistatin, inhibin, serglycin, spondin-1, fibrinogen, and anti-testosterone antibody were found during early stages of follicular development. In contrast, apolipoprotein H, alpha-2-macroglobulin, plasminogen, antithrombin-III, and immunoglobulins were increased after deviation. Among the differentially abundant proteins, 19 were found to be associated with steroidogenesis. Pathway analysis identified proteins that were mainly associated with the acute phase response signaling, coagulation system, complement system, liver/retinoid X receptor activation, and biosynthesis of nitric oxide and reactive oxygen. The differentially expressed proteins provide insights into the size-dependent protein changes in the ovarian follicle microenvironment that could influence follicular function.

The objective of the present study was to describe the proteins from the seminal plasma of buffalo and correlate these proteins with sperm motility. Ejaculates from sixteen Murrah buffalo were used. Semen collection was performed by electroejaculation, and the ejaculate was evaluated by macroscopic (volume) and microscopic analysis (subjective motility and vigor, as well as sperm concentration). After the analysis, the samples were centrifuged (800g for 10 min and 10,000 for 30 min at 4 °C), and the supernatant (seminal plasma) was used to determine total protein concentration by the Bradford method. Based on total protein concentration, an aliquot (50 μg) was taken to conduct protein in-solution digestion for nano-LC-ESI-Q-TOF mass spectrometry analysis. Samples were divided into two groups, minimal (little sperm motility) and greater (typical sperm motility), based on non-hierarchical clustering considering motility and emPAI protein value. The data were analyzed by multivariate statistical analysis using principal component analysis (PCA) and partial analysis of minimum squares discrimination (PLS-DA). Forty-eight proteins were detected in the seminal plasma, and fifteen were common to two groups. There were six proteins that were significantly different between the groups. The main functions of proteins in seminal plasma were catalytic and binding activity. Spermadhesin protein, ribonuclease, 14-3-3 protein zeta/delta and acrosin inhibitor were in greater amounts in seminal plasma from the group with greater sperm motility; prosaposin and peptide YY were in greater amounts in the group with little sperm motility. The proteins detected in the greater motility group were correlated with sperm protection, including protection against oxidative stress, lipid peroxidation, protease inhibition and prevention of premature capacitation and acrosome reaction. In the group with little sperm motility, one of the identified proteins is considered to be an antifertility factor, whereas the function of other identified protein is not definitive. Results from the present study add to the knowledge base about the molecular processes related with sperm motility, and these findings can be used for determining potential markers of semen quality.

No abstract

Heparin-binding proteins (HBP) from seminal plasma have been expected to participate in modulation of the acrosomal reaction, and have been correlated with fertility in some species. However, they have not been described in the dog. The aim of this study was to document the HBPs of canine seminal plasma. Six pooled samples of seminal plasma from three crossbred dogs were used. The HBPs were isolated by heparin affinity chromatography and the fractions recovered were pooled. One-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was carried out on 12 and 18% vertical minigels. The stained gels were scanned and the molecular weight (kDa) values for each band within a lane were calculated by image analysis software. The electrophoresis analysis of the pooled eluded fractions identified 19 bands, with molecular weights varying from 61.5 to 5.2 kDa. Previous studies, using one-dimensional SDS-PAGE, identified two bands (67 and 58.6 kDa), which were positively correlated with some semen parameters (sperm motility, sperm vigor, percentage of morphologically normal sperm and plasma membrane integrity). The 61.5 kDa band detected in the present study apparently corresponded to the 58.6 kDa band identified previously. Canine seminal plasma contained HBP; since HBP modulate the acrosome reaction in other species, they may have the same function in the dog. Further studies are necessary to better characterize this protein and determine if it is associated with fertility in the dog.

No abstract

ContentsThe collection of epididymal sperm is an option for preservation of germplasm of genetically superior animals that need to be orchiectomized or have died. The extender type used to freeze sperm is important to avoid spermatozoal membrane damage and to preserve semen quality after cryopreservation. The objective of this study was to verify the effects of a commercial bovine extender (Bovimix ® ; Nutricell, Campinas) and a traditional TRIS-citric acidglucose-egg yolk-7% glycerol extender on cryopreservation of canine epididymal sperm. The testes of 13 adult dogs were kept at 5°C for 24 h in saline solution, and epididymal sperm was recovered in Ringers solution without lactate and were evaluated for motility. Samples with ! 80% motility were pooled and then divided before dilution and packaging in 0.5 ml plastic straws, equilibration at 4°C for 1 h, freezing in nitrogen vapour for 20 min and storing at À196°C. The straws were thawed at 56°C for 10 s and were evaluated for motility by computer assisted analysis (CASA). The semen parameters, sperm movement index, linearity, total motility and rapid progressive motility were statistically higher in Bovimix ® than TRIS. In contrast, amplitude of lateral head displacement, slow sperm and static sperm were lower in Bovimix ® . Despite the high percentage of sperm defects in epididymal cells, regardless of the extender, we concluded that Bovimix ® is a viable alternative for the freezing of canine epididymal sperm. IntroductionDomestic dogs are not only companions but also excellent experimental models because of the similarity of the reproductive physiology with the wild species and humans. Obtaining semen directly from the epididymal tails and vas deferens is a technique that has been frequently used for the purposes of assisted reproduction (Martins et al. 2009). The process of cryopreservation may cause irreversible damage to the sperm membrane interfering with its viability. During the cryopreservation process, sperm cells are exposed to many stressors, which may be linked to thermal shock during cooling of the semen, the formation of intracellular ice crystals or osmotic shock during freezing and thawing or stress and action of cryoprotectants (Watson 2000). Therefore, choosing an extender with optimum properties for preserving sperm morphology and function may be the key to successful semen freezing. The aim of this study was to evaluate the effect on sperm viability using two different extenders, a commercial bovine extender (Bovimix ® ; Nutricell Ltda,Campinas, Brazil) and the Tris extender (Martins 2005) to freeze the epididymal spermatozoa. Materials and MethodsEpididymides were obtained from 13 mixed-breed dogs (age range 2-8 years, body weight <15 kg) by elective orchiectomy. After surgery, the testicles were kept at 5°C for 24 h in saline solution. After that time, the caudal portion of each epididymis and approximately 1.0 cm of the transition of epididymal tail into the deferential duct were squeezed into a Petri dish containing Ringers solution w...