Seminal plasma proteins and their relationship with sperm motility and morphology in boars

The identification of biomarkers associated with seminal traits could aid in the selection of higher quality ejaculates and benefit the swine industry. The objective of this study was to identify boar seminal plasma proteins associated with sperm motility and morphology. Twenty ejaculates from fifteen adult boars from a commercial boar stud were used for this work. After routine semen collection and analysis, ejaculates were classified into two groups: high‐quality semen (HQS) and low‐quality semen (LQS), based on sperm motility and morphology. Semen samples were processed for seminal plasma separation and analysis by 2D SDS‐PAGE. Total and progressive sperm motility differed between groups (p < 0.001), as well sperm morphology (p < 0.05). The intensity of spots identified as Major seminal plasma PSP‐I (PSP‐I) and cathepsin B (CTSB) was higher in LQS as compared to HQS samples (p < 0.05). Also, PSP‐I was positively associated with major and sperm cauda defects. Sperm motility was negatively correlated with both PSP‐I and cathepsin B. We conclude that high concentrations of Major seminal plasma PSP‐I and cathepsin B in boar seminal plasma are associated with reduced total and progressive sperm motility and low sperm morphology and might be used as biomarkers for semen quality.     

Seminal plasma lead, cadmium and zinc in relation to tobacco consumption

The total quantity of zinc in the ejaculates of smokers was sipficantly lower than in non-smokers. This was not related to a significant increase in the quantities of seminal cadmium or lead, or to a decrease in sperm quality in the smoking group. It appears that tobacco consumption may have to exceed 20 cigarettedday before a noticeable increase in seminal cadmium can be recorded. It is suggested that this reduction in zinc secretion may jeopardize the content of chromatin zinc, and thereby the stability of the sperm chromatin. This may then contribute to reproductive failure or have consequences for fetal development.     

冷冻保护剂与精液比例对冷冻复苏后精子活动力的影响

目的:比较冷冻保护剂与精浆的不同比例对人类精子冷冻复苏后活动力的影响。方法:将57例志愿者的精液标本分别采用冷冻保护剂∶精液=1∶1和冷冻保护剂∶精液=1∶3的体积比进行冷冻,比较精子复苏后的前向活动率和总活动率。结果:冷冻前的前向运动精子百分率和总活动率分别为(58.60±5.57)%和(66.17±5.24)%。采用冷冻保护剂∶精液=1∶1比例进行冷冻复苏后的前向运动精子百分率和总活动率分别为(40.53±8.97)%和(51.23±9.30)%;采用冷冻保护剂∶精液=1∶3比例进行冷冻复苏后的前向运动精子百分率和总活动率分别为(44.70±8.67)%和(51.50±7.40)%。冷冻前后精子的前向运动百分率和总活动率差异有显著性(P<0.05)。两种不同比例的保护剂相比冷冻后前向运动精子百分率差异有显著性(P<0.05),而总活动率差异没有统计学意义。结论:冷冻对精子活动力损伤明显,冷冻保护剂∶精液=1∶3比例较冷冻保护剂∶精液=1∶1比例可提高冷冻后前向运动精子百分率。     

Fertilization of hamster ova by human spermatozoa in relation to other semen parameters

Different indices of the zona-free hamster ovum test system were interrelated. High correlations were found between the fertilization percentage and the average number of penetrated spermatozoa/ovum (r = 0.99) and between the fertilization percentage and the number of spermatozoa attached to the ova surfaces (r = 0.72). Fertilization percentages from 63 subfertile patients were correlated with different semen factors assessed by multiple exposure photography (MEP). Low correlations were found between sperm concentration and fertilization percentage (r = 0.29) and between fertilization percentage and motile sperm count (r = 0.33). Spermatozoa progressing with high average velocity had low fertilization rates compared to specimen with moderate average velocity. Effects of sperm washing on the in vitro fertilizing capacity were studied in a group of 40 subfertile men. The fertilization percentages of 8 specimens -with visual seminal plasma abnormalities- increased significantly when immediate dilution of semen was applied.     

Seminal fibronectin in fertile and infertile males

This study aimed to assess seminal plasma fibronectin in fertile and infertile males. Ninety infertile males were investigated; asthenozoospermia (n = 27), asthenoteratozoospermia (n = 30), oligoasthenoteratozoospermia (n = 33) compared with 20 healthy fertile controls. They were subjected to semen analysis, seminal plasma fibronectin estimation by radial immune diffusion, serum testosterone (T) and follicle stimulating hormone (FSH) estimation by ELISA. There was significant increase of seminal plasma fibronectin among different infertile groups compared with the controls. Significant negative correlation was elicited between seminal fibronectin and sperm count, sperm motility grades A, B, A + B, sperm velocity, linear velocity, linearity index, sperm normal forms and serum T. Seminal fibronectin showed significant positive correlation with grade D sperm motility and serum FSH. ROC curve analysis discriminating controls and other infertile groups demonstrated criteria value of < 674 mg l(-1) (sensitivity 100% and specificity 96.4%). It is concluded that increased seminal fibronectin is associated with decreased sperm count and sperm motility.     

精浆转铁蛋白含量与不育的关系

为探讨精浆转铁蛋白 (Tf)含量与男性生育力的关系 ,采用速率散射比浊法 ,对 2 0例正常生育男性和 96例不育男性精浆Tf含量进行了测定 ,同时做精子密度、精子活动率及精子顶体完整率 (PIA)分析。结果表明少精子组 (精子密度 <2 0× 10 6/ml)精浆Tf含量较生育组与正常密度组 (精子密度≥ 2 0× 10 6/ml)显著低 (P <0 .0 1) ;精浆Tf含量与精子活动率无关 ;正常精子密度的不育患者精子PIA <80 %组精浆Tf的含量显著低于PIA≥ 80 %组(P <0 .0 1)。提示精浆Tf含量的下降与男性生育力有关     

The secretory activity of the seminal vesicles and its relationship to sperm motility: effects of infection in the male reproductive tract

In 146 males aged between 20 years and 40 years attending an infertility service, the secretory activity of the seminal vesicles was assessed by measurement of corrected seminal fructose concentration. This value was related to the presence of a positive semen culture, other evidence of inflammatory processes in the reproductive tract and sperm motility. Only 48% of subjects with a positive semen culture showed evidence of inflammation in the reproductive tract, as assessed by the presence of more than 20 white blood cells per high power field, and greater than 10% spermagglutination in the ejaculate. There was a relationship between the inflammatory process, hypofunction of the seminal vesicles and poor sperm motility. When the semen culture was positive but there was no evidence of inflammation neither seminal vesicle function nor sperm motility was affected. When the semen culture was negative, i.e. no evidence of inflammation and the subjects were asthenozoospermic, the corrected fructose levels were normal. It is proposed that in these conditions the cause of asthenozoospermia may be factors other than accessory sex organ dysfunction. In conclusion, there was no close relationship between the bacteriological results and evidence of inflammation of the accessory glands. A positive semen culture was related to lower levels of corrected fructose (hypofunction of the seminal vesicles) when the positive sperm culture was associated with inflammation of the reproductive tract and asthenozoospermia.     

Seminal plasma vitamin B6 levels in men with asthenozoospermia and men with normal sperm motility,a measurement using liquid chromatography with tandem mass spectrometry

There is growing evidence that vitamin B₆ has a valuable contribution in maintaining normal sperm parameters; however, this contribution has not yet well-identified. Here, we aimed to measure the level of seminal plasma vitamin B₆ in men with asthenozoospermia compared to men with normal sperm motility. Ninety-seven human males with asthenozoospermia and eighty-eight human males with normal sperm motility (control) were recruited in this study. Collected semen samples were assessed for sperm motility, sperm count and semen volume. Liquid chromatography with tandem mass spectrometry was used to measure seminal plasma vitamin B₆ concentrations. A highly significant difference (p < .0001) in concentrations of seminal plasma vitamin B₆ was found between asthenozoospermic and control groups. Besides, no statistical correlations were found between seminal plasma vitamin B₆ level and sperm motility, sperm count, semen volume and men age in both tested groups. In conclusion, men with asthenozoospermia have lower seminal plasma vitamin B₆ level compared to men with normal sperm motility. Also, seminal plasma vitamin B₆ was found not to be correlated with sperm motility and count, semen volume and men age in both tested groups. These results may provide new contribution in the management of male infertility.     

Seminal immunoreactive relaxin in domestic animals and its relationship to sperm motility as a possible index for predicting the fertilizing ability of sires

Although immunoassayable relaxin has been detected in human and boar seminal plasma, there is no evidence suggesting the existence of immunoreactive relaxin in the seminal plasma of other domestic animals. The first objective of this study was to determine whether immunoreactive relaxin was present in the seminal plasma of bulls, rams and he-goats. In addition, the correlation of immunoreactive relaxin with sperm motility as an index for predicting the fertilizing ability of bull sires was investigated. Semen with normal sperm motility was collected from bulls, rams and he-goats, and the relaxin immunoreactivity of the semen samples was measured using a time-resolved fluoroimmunoassay (TR-FIA) for porcine relaxin that we developed. The presence of relaxin immunoreactivity was demonstrated in seminal plasma from bulls, rams and he-goats. The level of immunoreactive relaxin in seminal plasma was the highest in bulls followed by humans, rams, boars and he-goats in that order, when relaxin levels in boar and human semen having normal sperm motility were also assayed under the same conditions. When the correlation between the seminal plasma level of immunoreactive relaxin and sperm motility was examined in bull semen samples as an index for predicting fertilizing ability, it was found that the relaxin level was significantly correlated with the percentage of spermatozoa showing the most intensive motility (r = 0.64, p < 0.05). These results indicate that immunoreactive relaxin is widely found in the seminal plasma of domestic animals and that measuring the relaxin concentration of seminal plasma may be useful to identify subfertile sires or predict the fertility potential of individual sires.     

Effects of long-term in vitro incubation of human spermatozoa: functional parameters and catalase effect

Prolonged incubation of human spermatozoa can have deleterious effects on sperm function. The aim of this paper was to describe the effects of a prolonged in vitro incubation, under similar conditions to those employed in human assisted reproduction, on various sperm functional parameters, and to investigate the effect of an antioxidant (catalase) on this system. Freshly collected ejaculates from 20 healthy donors were studied. Samples were divided into two aliquots: the first was incubated with Ham's F10 containing 3.5% HAS, and the second was incubated in the same medium plus catalase (100 units ml-1). All experiments were carried out with spermatozoa isolated using the swim-up technique. Spermatozoa recovered from the supernatant after 1 h (T1) of incubation in 5% CO2 in air at 37 degrees C, and after 5 h (T6), 23 h (T24) and 47 h (T48), were evaluated for concentration, motion parameters including hyperactivation (computer-assisted analysis), viability, ATP concentration, reactive oxygen species (ROS) generation, DNA integrity (acridine orange), and acrosome reaction (AR). The major alteration observed in sperm function during the prolonged in vitro incubation was a reduction in the number of motile spermatozoa, together with an impairment in the quality of sperm movement. ROS levels increased with the incubation time. No substantial modifications of sperm viability, chromatin condensation and AR inducibility were observed. The addition of catalase to the medium, while keeping ROS values within baseline levels, did not prevent the loss of motility or the corresponding increase in ATP.     

Glycerophosphocholine in seminal plasma of fertile and infertile men

Glycerophosphocholine (GPC) was measured in seminal plasma from 65 fertile men, 276 infertile men and 10 men before and after vasectomy, using a new enzymatic method. Extra-epididymal excretion of GPC accounted for 30% of the total seminal levels of GPC. From a diagnostic point of view, GPC determination did not appear to be a specific tool which could discriminate between secretory and excretory azoospermia. Although the seminal content of GPC was related positively to the total sperm count in both fertile and infertile men, there was an inverse relationship between the level of GPC and sperm motility when considering classes displaying the same total sperm count. This was observed in all classes from infertile men as well as in fertile men with a total sperm count lower than 200 x 10(6) sperm/ejaculate. These results suggest a possible role of GPC in the regulation of human sperm motility, which warrants further investigation.     

Quercetin impairs the reproductive potential of male mice

Oxidative stress is a leading cause of male infertility. To combat this, germ cells and spermatozoa are endowed with various enzymes, vitamins and proteins. Certain other components of food, including bioflavonoids, also provide protection against free radicals. This study analysed the effect of quercetin, a bioflavonoid, on male reproductive function in adult mice, after intraperitoneal treatment with varying concentrations of quercetin (2, 8 and 20 mg kg^?1 b.wt.) for 2 weeks. Quercetin increased the generation of reactive oxygen species and lipid peroxidation in the testis with concomitant decrease in sperm count and motility in a dose‐dependent manner. Activities of antioxidant enzymes catalase, superoxide dismutase and levels of reduced glutathione were found to be decreased in a dose‐dependent manner. Also, the levels of oxidised glutathione were increased leading to a shift in redox ratio. The testicular histomorphology was also altered dose dependently. Germ cell kinetic study revealed significant loss of various germ cell populations with increasing dose of quercetin. Interestingly, there was a reduction in germinal epithelium thickness concomitant with an increase in seminiferous tubule lumen diameter. In conclusion, the deleterious effects of quercetin on germ cells could be attributed to its pro‐oxidant ability that might affect the Sertoli cell functions.     

Pharmacokinetic and pharmacodynamic studies of the effect of ketoconazole on reproductive function in male rats

A single oral dose (300 mg kg-1) of ketoconazole induced reversible immobilization of rat epididymal spermatozoa at 8-24 h after dosing. This occurred when the drug concentrations in cauda epididymal fluid and seminal plasma were at their peak (18.0 +/- 7.3 and 13.5 +/- 3.0 micrograms ml-1, respectively), and which was preceded by a peak plasma concentration (Cmax) of 64.82 +/- 2.47 micrograms ml-1 at 5.15 +/- 0.68 h (Tmax). In contrast, rete testis fluid collected from the same animals contained only minute amounts of ketoconazole (0.47 +/- 0.34 micrograms ml-1). Plasma testosterone concentration showed a sharp decline within 4 h of dosing, followed by a recovery from suppression, even after administration of a low dose (100 mg kg-1) which did not affect sperm motility. These findings suggest that ketoconazole gains access to the post-testicular sex organs and affects the mature spermatozoa therein much more readily than it affects testicular spermatogenesis. Synthesis and screening of compounds with a related molecular structure but which exhibit more pronounced spermicidal and less pronounced anti-androgenic effects are thus suggested in the hope that rapidly acting and reversible male contraceptives might be identified and developed.     

Effect of transient scrotal hyperthermia on sperm parameters,seminal plasma biochemical markers,and oxidative stress in men

In this experimental prospective study, we aimed to analyze the effect of transient scrotal hyperthermia on the male reproductive organs, from the perspective of sperm parameters, semen plasma biochemical markers, and oxidative stress, to evaluate whether different frequencies of heat exposure cause different degrees of damage to spermatogenesis. Two groups of volunteers (10 per group) received testicular warming in a 43°C water bath 10 times, for 30 min each time: group 1: 10 consecutive days; group 2: once every 3 days. Sperm parameters, epididymis and accessory sex gland function, semen plasma oxidative stress and serum sex hormones were tested before treatment and in the 16-week recovery period after treatment. At last, we found an obvious reversible decrease in sperm concentration (P = 0.005 for Group 1 and P= 0.008 for Group 2 when the minimums were compared with baseline levels, the same below), motility (P = 0.009 and 0.021, respectively), the hypoosmotic swelling test score (P = 0.007 and 0.008, respectively), total acrosin activity (P = 0.018 and 0.009, respectively), and an increase in the seminal plasma malondialdehyde concentration (P = 0.005 and 0.017, respectively). The decrease of sperm concentration was greater for Group 2 than for Group 1 (P = 0.031). We concluded that transient scrotal hyperthermia seriously, but reversibly, negatively affected the spermatogenesis, oxidative stress may be involved in this process. In addition, intermittent heat exposure more seriously suppresses the spermatogenesis compared to consecutive heat exposure. This may be indicative for clinical infertility etiology analysis and the design of contraceptive methods based on heat stress.     

Ontogeny and cellular origin of an interleukin-1 -like factor in the reproductive tract of the male rat

We have recently isolated an interleukin-1 (IL-1)-like factor from the rat testis, which originates from the seminiferous tubules and is a protein with an MW of 17,000 and a pI of 5-6. This paper reports on the appearance of the IL-1-like factor during postnatal development and investigates its cellular origin further. IL-1 activity was measured by a murine thymocyte proliferation assay. Very low IL-1 activity was present in culture medium conditioned by seminiferous tubules from rats aged 10 or 20 days. From 30 days of age, increasing amounts were detected, reaching a maximum level in adult animals (60-90 days). No IL-1 activity was found in medium conditioned by peritubular cells. Sertoli cell-enriched seminiferous tubules obtained from experimentally cryptorchid or from prenatally irradiated rats produced much higher levels of IL-1 activity than did those obtained from intact testes. IL-1 activity was detected in efferent duct fluid after ligation of the efferent ducts for 24 h, indicating that the IL-1-like factor was secreted into the tubular lumen. Low levels of IL-1 activity were detected in extracts of epididymal tissue and epididymal sperm, whereas ejaculated seminal plasma, seminal vesicle fluid and extracts of seminal vesicles (together with the coagulating glands) and ventral and dorsolateral prostate lacked IL-1 activity. Instead, seminal plasma inhibited testicular IL-1 activity dose-dependently without affecting cell viability in the thymocyte cultures. Although its biological function remains to be defined, our results indicate that the testicular IL-1-like factor is produced by Sertoli cells and that its appearance during development coincides with the initiation of active spermatogenesis in the rat testis.     

Leptin exists in tubuli seminiferi and in seminal plasma

Leptin is a 167-amino acid protein that stimulates gonadotrophin-releasing hormone secretion and exerts indirect effects on the gonads via neuropeptide Y, NPY. Recent research has suggested that leptin may also have an effect on testosterone secretion. To investigate the role of leptin in reproduction, leptin in testicular tissue and seminal plasma was examined in relation to leptin in serum, semen sample qualities and vasectomy. Seminal plasma and serum of 64 infertility patients, and 15 individuals after vasectomy, were assayed for leptin using a competitive 'in house' radioimmunoassay. The concentration of leptin in seminal plasma was significantly lower in the 'normal' semen sample group than in the 'pathological' group (Mean +/- SEM; 1.45 +/- 0.18 vs. 3.19 +/- 0.57 ng ml-1; P < 0.05), and showed a significantly negative correlation with percentage of motile spermatozoa (r = -0.46; P = 0.0005) and with the velocity straight line, VSL, (r = -0.30; P = 0.029). In contrast, leptin concentration in serum did not show any relationship with the spermiogram parameters. In testicular tissue, leptin was preferentially found within the tubuli seminiferi using anti-leptin polyclonal antibody, Ob A-20 Sc 842. The amount of leptin per ejaculate did not significantly change after vasectomy, and was not correlated to fructose, zinc or neutral alpha glucosidase in seminal plasma (P > 0.05). These results suggest that the amount of leptin in the genital tract, including the tubuli seminiferi, may influence the mechanisms involved in the motility development of spermatozoa.     

Semen quality in fertile US men in relation to geographical area and pesticide exposure

We conducted the first US study to compare semen quality among study centres using standardized methods and strict quality control. We present data on semen quality in partners of 493 pregnant women recruited through prenatal clinics in four US cities during 1999-2001. Sperm concentration, semen volume and motility were determined at the centres and morphology was assessed at a central laboratory. While between-centre differences in sperm morphology and sample volume were small, sperm concentration and motility were significantly reduced in Columbia, MO (MO) relative to men in New York, NY, Minneapolis, MN and Los Angeles, CA; total number of motile sperm was 113 x 10(6) in MO and 162, 201 and 196 x 10(6) in CA, MN and NY respectively. Differences among centres remained significant in multivariate models that controlled for abstinence time, semen analysis time, age, race, smoking, history of sexually transmitted disease and recent fever (all p-values <0.01). We hypothesized that poorer sperm concentration and motility in MO men relative to other centres might be related to agricultural pesticides that are commonly used in the mid-west. We investigated this hypothesis by conducting a nested case-control study within the MO cohort. We selected 25 men in this cohort for whom all semen parameters (concentration, % normal morphology and % motile) were low as cases and an equal number of men for whom all semen parameters were within normal limits as controls. We measured metabolites of eight non-persistent, current-use pesticides in urine samples the men had provided at the time of semen collection. Pesticide metabolite levels were elevated in cases compared with controls for the herbicides alachlor and atrazine, and for the insecticide diazinon (2-isopropoxy-4-methyl-pyrimidinol) (p-values for Wilcoxon rank test = 0.0007, 0.012, and 0.0004 for alachlor, atrazine and diazinon respectively). Men with higher levels of alachlor or diazinon were significantly more likely to be cases than men with low levels [odds ratios (OR) = 30.0, 16.7 for alachlor and diazinon respectively], as were men with atrazine over the limit of detection (OR = 11.3). These associations between current-use pesticides and reduced semen quality suggest that agricultural chemicals may have contributed to the reduced semen quality seen in fertile men from mid-Missouri.     

Hyperprolactinaemia and hyperserotoninaemia: their relationship to seminal quality

Seminal quality and levels of blood serotonin (5-HT) and serum prolactin (PRL) were determined in 60 men attending an infertility service. Subjects were grouped according to normal or abnormal accessory sex gland function. Subjects with normal accessory sex gland function were further subdivided into groups with asthenozoospermia, polyzoospermia, normozoospermia, oligozoospermia, or azoospermia. Blood 5-HT levels were significantly higher in oligozoospermics (115.9 +/- 23.7 ng ml-1, P less than 0.05), and asthenozoospermics (90.0 +/- 8.2 ng ml-1, P less than 0.05), than in normals (68.5 +/- 5.3 ng ml-1), whereas serum PRL levels were higher in azoospermics (44.2 +/- 4.7 ng ml-1) than in normozoospermics (15.9 +/- 1.6 ng ml-1, P less than 0.01). Subjects with abnormal accessory sex gland function were also subdivided according sperm count and sperm motility categories. None of these subgroups showed differences in serum PRL levels or blood 5-HT levels. Men with hyperserotoninaemia had higher serum PRL levels, low sperm count, and low motile sperm concentration. Moreover, higher 5-HT levels may be observed in men with normal PRL levels and also associated with normal PRL levels and with hyperprolactinaemia, and hyperprolactinaemia may be observed also associated with normal serotonin levels. Hyperserotoninaemia was related to both diminished sperm count and sperm motility, whereas hyperprolactinaemia was related to low sperm count. When hyperprolactinaemia and hyperserotoninaemia were both present, additive effects were observed.     

Seminal fluid from men with agenesis of the Wolffian ducts: zinc-binding properties and effects on sperm chromatin stability

Zinc-binding properties were studied in 'prostatic fluid', i.e. in seminal plasma from patients with agenesis of the Wolffian ducts, and in split-ejaculate fractions dominated by seminal vesicular fluid. The effect of seminal fluid, with different zinc-binding properties, on the stability of zinc-dependent sperm chromatin was assessed by exposing sperm to 1% sodium dodecyl sulphate (SDS) for 60 min. Citrate was the only zinc ligand in 'prostatic fluid', as revealed by gel chromatography. Zinc in this fluid enhanced the stability of sperm chromatin. In contrast, the stability of sperm chromatin was decreased in seminal plasma dominated by vesicular fluid. These results are in accordance with the concept that prostatic fluid ensures the appropriate zinc content and stability of sperm chromatin, whereas abundance of vesicular fluid may jeopardize chromatin stability by reducing chromatin zinc content.