Rat cauda epididymal fluid is a mucus

Immobilin, the highly viscoelastic glycoprotein isolated from rat cauda epididymal fluid, exhibits all of the key biochemical characteristics of a mucin: 1) it has a very high molecular weight (will not pass through a 10(6) dalton cut-off filter; 2) it contains 56% carbohydrate, with low or undetectable levels of mannose, xylose and uronic acid; 3) the carbohydrates (primarily galactose, N-acetylglucosamine and N-acetylgalactosamine) are arranged in short, oligosaccharide chains (4-20 monosaccharides per chain); 4) these oligosaccharide chains can be cleaved by NaOH in the presence of NaBH4, suggesting O-glycosidic linkages; and 5) the protein core is pronase-resistant. Immobilin, however, contains no detectable sialic acid, and 67% of the oligosaccharides are uncharged, indicating that immobilin is less acidic than most other mucins.     

Isolation and characterization of the plasma membrane of rat cauda epididymal spermatozoa

Cauda epididymal rat spermatozoa were isolated by flushing the excised epididymis and the plasma membrane was detached by a nitrogen cavitation treatment (500 psi, 10 minutes equilibration at 4 C). Membrane vesicles were recovered after sucrose gradient centrifugation. Portions of the sperm surface releasing the plasma membrane were assessed by light microscopy of fluoroscein isothiocyanate-succinylated concanavalin A-treated spermatozoa and by transmission electron microscopy. Plasma membrane was detached from the region overlying the acrosome from most spermatozoa and from the middle-piece overlying the mitochondria from some cells. Thus, the fraction analyzed was derived from at least two portions of the sperm surface. The fractions from the sucrose density gradient were analyzed for gross chemical composition (phospholipid, protein and sterol) and the protein components were detected after electrophoresis under denaturing conditions; the peak fractions (at density approximately 1.13 g/ml) were judged homogeneous. Replicate analyses of such preparations established mass ratios of protein to phospholipid of 0.63, total sterol to phospholipid of 0.18, and demosterol to cholesterol of 0.32. The molecular composition of the phospholipid fraction was determined to be 10% phosphatidylserine (mole percent), 3% phosphatidylinosital, 3% sphingomyelin, 31% phosphatidylethanolamine, 27% phosphatidylcholine, 10% diphosphatidylglycerol and 5% of an unknown component. Fatty acyl analyses of the phospholipid fraction revealed that approximately 70% of the residues consisted of palmitoyl (16:0) and stearoyl (18:0) acyl groups, with the balance distributed among various unsaturated acyl groups (18:1, 22:3, 22:4 and 22:5); about 40% of the recovered phospholipids represented ether acyl phosphatides. Differences in the lipid composition of rat vesicles described here and similar vesicles isolated from ram and boar spermatozoa (described previously) are discussed. The partitioning of the nitroxyl spin label 3-doxylheptane into vesicles isolated from rat and ram spermatozoa was assessed by electron paramagnetic resonance spectroscopy at temperatures between 4 C and 26 C; no difference in the response of the spin label in the two vesicle preparations was detected.     

大鼠精子在附睾成熟中精子膜变化的研究

我们运用Ｐｅｒｃｏｌｌ离心技术对ＳＤ大鼠附睾头、体、尾各段的精子分离纯化后，再用硫代巴比妥酸法、酶法、ＳＤＳ－ＰＡＧＬ电泳技术等对精手膜依次进行唾液酸、甘油－３－磷酸胆碱（ＧＰＣ）及蛋白质含量变化的检测。结果显示：精子膜唾液酸、ＧＰＣ量不断降低且有显著统计学意义（Ｐ＜０．０１）。附睾头、体、尾各段精子膜唾液酸和ＧＰＣ量分别为１０．１８±２．８２、８．４２±３．０７、７．８３±２．７９μｇ／１０８精子；１１２．３１±２８．１４、１０９．３３±３７．１６、７４．５０±２５．１３ｎｍｏｌ／１０８精子（－ｘ±ｓ）。膜蛋白变化主要是由大分子蛋白转变成较小分工的蛋白。大鼠精子附睾转运中精子膜的变化与精子成熟具有十分密切的关系。     

Proteins of the cauda epididymal fluid associated with fertility of mature dairy bulls

We evaluated the relationships between proteins in cauda epididymis fluid (CEF) and fertility scores of dairy bulls. Fertility was expressed as the percentage point deviation (PD) of bull nonreturn rate from the average fertility of all bulls at an artificial insemination center. The number of services for each bull ranged from 1074 to 52 820, and PD values ranged from +7.7% to -6.6%. CEF from 20 bulls was obtained from vasa deferentia cannulae and was separated from sperm by centrifugation immediately after collection. Samples were evaluated by 2-dimensional (2-D) sodium dodecyl sulfate polyacrylamide gel electrophoresis gels stained with Coomassie blue, and polypeptide maps were analyzed by PDQuest software. Protein quantities, defined as the total integrated optical density of the spots, were compared between groups of high-fertility sires (n = 12; PD >or= 0) and low-fertility sires (n = 8; PD < 0) and were also used as independent variables in regression analysis. Proteins were identified by capillary liquid chromatography-nanoelectrospray ionization-tandem mass spectrometry. An average of 118 spots was detected in 2-D maps of the CEF, but we were unable to distinguish any protein that was expressed only in high-fertility or in low-fertility bulls. However, the amount of alpha-L-fucosidase 2 and cathepsin D was 2.3- and 2.4-fold greater (P < .05) in high-fertility than in low-fertility bulls, respectively. Conversely, the intensities of 3 isoforms (24-27 kd; pl 6.3-5.8) of prostaglandin D-synthase (PGDS) were from 3.2- to 2.2-fold greater in low-fertility sires (P < .05). An empirical regression model established that a significant proportion (R(2) = 0.72; P < .0001) of the variation in fertility scores (PD values) was explained by the intensities of cathepsin D and 1 isoform of PGDS (24 kd; pl 6.3). Thus, multiple proteins present in the CEF are potential biomarkers of fertility in high-use, mature Holstein bulls.     

非阻塞性输精管滤过装置节育术的精浆中性α-糖苷酶的检测

本文采用ＷＨＯ推荐的改良精浆中性α－糖苷酶的测定方法测定输精管滤过装置节育术（ＩＶＤ组）和输精管结扎术（结扎组）的精浆中性α－糖苷酶活性。术前两组精浆均测出中性α－糖苷酶活性：ＩＶＤ组为４３．５０±２９．０１ｍＵ／每次射精（ｘ±ｓ）；结扎组为４７．８１±３１．２０（ｘ±ｓ）ｍＵ／每次射精；两组间无显著差异（Ｐ＞０．０５）。术后６、１２个月ＩＶＤ组分别有９１．５７％和７９．１７％的精浆测出中性α－糖苷酶活性；而结扎组仅有４．４８％和４．２４％的精浆测出中性α－糖苷酶活性；两组间均有非常显著的差异（Ｐ＜０．００１）。结果提示：ＩＶＤ组术后一年内其大部分受试对象的精浆中仍有附睾液存在。     

Nonprotein thiols and disulfides in rat epididymal spermatozoa and epididymal fluid: role of gamma-glutamyl-transpeptidase in sperm maturation

Sperm thiol oxidation during sperm maturation is important for sperm component stabilization, the acquisition of sperm motility, and fertilizing ability. A correct degree of oxidation is required, since spermatozoa are very susceptible to oxidative damage. The pathways involved in physiologic sperm thiol oxidation in the epididymis are not completely understood. The nonprotein thiol glutathione (GSH), in addition to playing a major role as an antioxidant and in eliminating toxic compounds, has been implicated in prooxidation processes in various cells, via gamma-glutamyl-transpeptidase (gamma-GT)-dependent catabolism. Little information is available on the dynamics of nonprotein thiols (NPSHs) and disulfides (NPSSNPs) in spermatozoa and epididymal fluid (EF) during sperm passage in the epididymis. It is not clear whether NPSHs and NPSSNPs are involved in sperm protein thiol (PSH) oxidation or whether GSH catabolism in the epididymis can serve as a pathway for sperm PSH oxidation. In the present study, we used the thiol fluorescence labeling agent monobromobimane to analyze NPSHs and nonprotein disulfides (NPSSRs) (R, nonprotein or protein) in spermatozoa and EF in the rat caput and cauda epididymis. NPSH levels are shown to be significantly higher in the caput than in the cauda (spermatozoa and fluid). GSH in the caput lumen is subject to high gamma-GT activity. A marked loss of sperm GSH and a shift to an oxidized state (resulting in a significantly higher concentration of glutathione disulfides [GSSRs] than GSH) occur during the passage of spermatozoa from the caput to the cauda epididymis. Caput EF and extracellular NPSSNPs induce sperm thiol oxidation. The results suggest that epididymal NPSH/NPSSNP participates in sperm PSH oxidation and that some reactions of GSH in the gamma-GT pathway (in the epididymis) provide oxidizing power, leading to physiologic sperm thiol oxidation.     

Posttesticular antifertility action of triptolide in the male rat: evidence for severe impairment of cauda epididymal sperm ultrastructure

A variety of active diterpene epoxides, including the triptolide (isolated from Tripterygium wilfordii) have been reported to cause infertility in male rats. Previously, we showed that oral administration of triptolide at a dosage of 100 microg/kg per body weight for 70 days completely inhibited fertility in male rats, with little or no demonstrable detrimental effect on spermatogenesis and Leydig cell function as determined by testicular light microscopic appearance and serum and intratesticular testosterone levels. Despite the apparent absence of effects on the testes, cauda epididymal sperm were abnormal, with complete cessation of sperm motility and some reduction in sperm numbers. This study was undertaken to provide additional insight into the subcellular sites and possible mechanisms of action of this compound using ultrastructural analysis of the testes and epididymidis. The most striking effect of triptolide treatment was observed in sperm in the epididymis. In rats rendered infertile with 100 microg/kg per body weight of triptolide daily for 70 days, virtually all cauda epididymal sperm exhibited complete absence of plasma membrane over the entire middle and principal piece, premature decondensation of the nuclei, and disorganization of the mitochondrial sheath with many vacuolated mitochondria. No ultrastructural differences in the epididymal epithelium were observed between control and triptolide-treated rats. The testes appeared to be mildly affected after triptolide treatment but exhibited only subtle ultrastructural defects in the germ cells. The findings of severe impairment of cauda epididymal sperm ultrastructure, along with minimal discernible abnormalities in the fine structural cytology of the testes, further suggest that the site of action of this compound is posttesticular and may be confined to the cauda epididymal sperm. However, we cannot rule out an effect of triptolide that occurs during germ cell maturation but is delayed in its manifestation or triggered at the rete testis and epididymal level.     

In vitro inhibition of rat cauda epididymal sperm glycolytic enzymes by ornidazole, alpha-chlorohydrin and 1-chloro-3-hydroxypropanone

Chlorinated antifertility compounds are known to inhibit glycolysis of spermatozoa as they reside in the epididymis but new compounds need to be evaluated that retain antifertility action but do not exhibit side-effects. In this study, two known antifertility agents and a related compound were compared for their inhibition of rat sperm metabolism and motility in vitro. The dose-dependent inhibition in vitro of the glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and triosephosphate isomerase (TPI) of distal cauda epididymal rat spermatozoa by (R)-, (S)- and (R,S)-ornidazole (ORN), (R,S)-alpha-chlorohydrin (ACH) and 1-chloro-3-hydroxypropanone (CHOP) was compared. The direct inhibition of GAPDH by ORN suggests that it inhibits without prior conversion outside the cell but inhibition was not stereo-specific. The GAPDH, but not TPI, activity of spermatozoa incubated with ACH and CHOP was highly correlated with kinematic parameters of spermatozoa incubated in pyruvate- and lactate-free medium. ACH only inhibited the activity of intact spermatozoa and the inhibition was not reversed by washing the particulate sperm fraction after sonication. High concentrations of ACH (100 mmol/L) killed intact rat spermatozoa and decreased the extent of GAPDH inhibition. CHOP, unlike ACH, was an effective inhibitor of both intact and sonicated cells. Pre-CHOP, the dimethylketal precursor of CHOP, and its other hydrolysis product MeOH, were both ineffective in vitro. CHOP and related ketals may be more effective inhibitors of sperm glycolysis than ACH and may prove useful for investigating sperm-specific glycolytic inhibition, a prerequisite for the development of antiglycolytic, post-testicular acting contraceptives.     

Patterns of human epididymal fluid proteins on polyacrylamide gel electrophoresis

Proteins were analysed by sodium dodecylsulphate polyacrylamide gel electrophoresis in fluid taken from six epididymal regions in 10 men undergoing microsurgery to bypass epididymal obstructions resulting from various disorders. Some major proteins common to most samples were identified with apparent molecular weights of 95, 67, 56, and 44 kilodaltons. A degree of regional specificity in the synthesis and secretion of epididymal proteins was indicated. There appeared to be no correlation between protein pattern or the abundance of individual proteins and the cause of obstruction, although methodological constraints may have partially obscured any such relationship.     

Correlation between changes in rat sperm membrane lipids, protein, and the membrane physical state during epididymal maturation.

An enriched plasma membrane fraction was isolated from caput, corpus, and cauda rat spermatozoa and analyzed for lipid and protein content, thermal phase transition temperature using electron paramagnetic resonance spectroscopy (EPR), and enzymatic assays of calcium-dependent ATPase activity. Based on sperm concentration, total membrane phospholipid, cholesterol, and protein content declined as sperm passed through the epididymis. A more refined analysis of the bulk plasma membrane phospholipid revealed that approximately 56% of the phospholipid consisted of choline (PC) and ethanolamine (PE) phosphoglycerides; the remainder consisted of sphingomyelin (SM), phosphatidylserine (PS), and diphosphatidylglycerol (DPG). The mole percent of PE increased in sperm proceeding from the caput to the corpus epididymis and then declined from the corpus to the cauda epididymis. The phospholipid-bound fatty acids consisted primarily of palmitate (C16:0) and stearate (C18:0), with a significant increase in the mole percent of the docosapentenoyl acyl group (C22:5) in cauda sperm. Arrhenius' plots of the EPR peak height signals using the lipid soluble spin label, 5-doxyldecane, and the calcium-dependent ATPase activity as a function of temperature demonstrated a change in the apparent fluidity of the membrane and energy of activation of the calcium-dependent ATPase associated with the three sperm membrane preparations. These data suggest that the apparent fluidity and biochemical composition of the sperm membrane change during epididymal maturation.     

α-Mannosidase from rat epididymal fluid is a ligand for phosphomannosyl receptors on the sperm surface

This study demonstrates that α-mannosidase from rat epididymal fluid is a ligand for phosphomannosyl receptors on the sperm surface. This enzyme was bound to intact epididymal spermatozoa with high affinity and in saturable form, and the binding was inhibited by mannose-6-phosphate but not by phosphorylated derivatives of fructose. Treatment of the enzyme with sodium periodate inhibited the binding of α-mannosidase, confirming that a carbohydrate residue is involved in the interaction with spermatozoa. Evidence is also presented that the cation-independent phosphomannosyl receptors are responsible for the interaction with α-mannosidase. These findings suggest a new role for extracellular transport mediated by the mannose-6-phosphate receptor.     

计算机辅助分析人、家兔、大鼠和小鼠附睾精子运动能力

本研究应用计算机辅助精子分析（ＣＡＳＡ）定量分析了人、家兔、大鼠和小鼠精子附睾成熟过程中，精子运动能力的发生和发展。同时对这几种动物和人进行了系统分析和比较。结果表明：在不同种属之间，其运动的发生和发展具有一定的差异；各种不同种属动物精子在各自附睾成熟过程中，其运动能力的两个方面参数，运动速度和运动方式的发展是不平行的；附睾尾部精子的运动能力（包括运动速度和直线程度）最强。     

Increase in fluid viscosity during epididymal transit and the immobilization of rat epididymal spermatozoa

A microcapillary method was developed to measure the viscosity of small volumes of undiluted epididymal fluid. Fluid from the cauda epididymis registered 82 +/- 17 centipoise which was much more viscous than fluid from the caput region (8 +/- 2 centipoise). Initiation of sperm motility was strongly suppressed in the viscosity range of 7 to 150 centipoise. A significant increase in the viscosity of fluid from the caput region was observed when immobilin in the fluid binds with a lectin from Jack fruit (Artocarpus heterophyllus). Thus, it is postulated that aggregation of the immobilin induced by a lectin-like material produced by the cauda epididymis may be a mechanism by which fluid viscosity is increased during epididymal transit.     

Microsurgical vasovasostomy versus microsurgical epididymal sperm aspiration/testicular extraction of sperm combined with intracytoplasmic sperm injection. A cost-benefit analysis

PURPOSE: Vasovasostomy (VVS) represents the standard therapy of choice for the treatment of obstructive azoospermia following vasectomy. However, recently, intracytoplasmic sperm injection (ICSI) has been suggested by some to represent the solution for all cases of malefactor infertility regardless of its etiology based on its success rates. Therefore, we compared VVS to microsurgical epididymal sperm aspiration (MESA)/testicular extraction of sperm (TESE) and ICSI in terms of pregnancy, complications, and costs. PATIENTS AND METHODS: Between 1/93 and 6/98, 157 VVS were performed microsurgically using the double-layer technique. Between 9/94 and 9/97, 69 and 42 couples underwent MESA/ICSI and TESE/ICSI, respectively, for epididymal obstruction and azoospermia of testicular origin. RESULTS: The mean interval of vasal obstruction was 7.6 (0.5-18) years; patency after VVS was 77%, pregnancy rate was 52%. Local complication rate was 4.7%, no major complications were observed. Costs per life birth after VVS were 5,447 DM or 2,793 Euro. Pregnancy rates after MESA/TESE and ICSI were 22.5 and 19.5%, respectively, with 16 singletons, 3 twins and 3 abortions; local complications occurred in 3.9% of the men. Multiple births were noticed in 15.8% following ICSI, but in only 0.7% following VVS. 5.7 and 1.4% of the female partners experienced serious complications (mild or severe ovarian hyperstimulation syndrome, respectively). Costs per life birth after a MESA/TESE cycle amounted to 28,804 DM or 14,547 Euro. CONCLUSIONS: Even in the era of ICSI, microsurgical VVS represents the standard approach for obstructive azoospermia following vasectomy. Based on a cost-benefit analysis, VVS is more successful in terms of pregnancy rates (52 vs. 22.5%). VVS does not expose the female partners to complications following treatment of male infertility. In contrast to ICSI, multiple birth rates do not increase after VVS. We conclude that MESA/ICSI should be reversed for patients who are not amenable for microsurgical reconstruction.     

Alloplastic spermatocele: poor sperm motility in intraoperative epididymal fluid contraindicates prosthesis implantation

After vasectomy reversal by vasovasostomy or vasoepididymostomy motile sperm appear commonly in the semen even when only nonmotile sperm are present in the intraoperative vasal or epididymal fluid. We studied patients with bilateral congenitally absent vasa deferentia to see if relief of obstruction by implantation of an alloplastic spermatocele also benefits sperm motility in such patients. A total of 130 alloplastic spermatoceles was implanted in 91 patients. Of 21 patients with only nonmotile sperm in the epididymal fluid intraoperatively only 1 had motile sperm in the postoperative aspirates from the alloplastic spermatocele. The quality of sperm motility in the intraoperative epididymal fluid was predictive of the quality of sperm motility in the postoperative aspirates. Conception postoperatively did not occur whenever less than 20 per cent of the intraoperative epididymal sperm was motile. Thus, poor or absent sperm motility in the epididymal fluid during planned alloplastic spermatocele implantation predicts a poor postoperative result and, therefore, contraindicates implantation of the prosthesis. Pregnancy, which occurred postoperatively in 7 of 91 wives, ended in spontaneous abortion in 3 and progressed to full-term delivery in 4.     

The correlation between the gossypol contents in blood plasma, rete testis fluid, and cauda epididymal fluid following chronic treatment with gossypol in rats

Concentrations of gossypol in blood plasma, rete testis fluid, and fluid from the caudia epididymidis were measured simultaneously by high performance liquid chromatography in rats treated with gossypol (15 mg/kg daily for 3 weeks). Antispermatogenic effects were demonstrated by loss of sperm motility in the cauda epididymidis and structural changes in the testis. It was found in these treated rats that concentrations of gossypol were lower in rete testis fluid compared with blood plasma but increased significantly in fluid from the cauda epididymidis. The results indicate a restriction of the blood-testis barrier to gossypol and its local concentration in the epididymis after fluid resorption.     

Changes in the content of rat epididymal fluid induced by prolonged treatment with Tamoxifen

Summary.  Prolonged treatment with tamoxifen induces changes in the male reproductive tract in rats. In this study changes in the protein content of the rat epididymal fluid as a consequence of prolonged treatment with tamoxifen are reported. Among five lysosomal enzymes measured in the epididymal fluid, α-mannosidase (α-MAN) significantly diminished, but other enzymes did not. Electrophoretic analysis of fluids showed that proteins of estimated molecular weight 25, 60, 80–85 and 180 kDa decreased in the treated rats. We also detected an increase in the binding of β-galactosidase (β-GAL) to caudal spermatozoa in treated rats. These changes may be related in part to the loss of fertilizing capacity of spermatozoa after tamoxifen treatment.     

大鼠卵泡颗粒细胞条件培养液对精子顶体反应的影响

使用 McCoy's 5A 无血清培养液培养未成熟大鼠的卵巢颗粒细胞,取颗粒细胞条件培养液与大鼠精子共同孵育后,以 FITC-ConA 标记精子顶体内膜,用荧光显微镜观察对精子顶体反应率的影响。结果表明:几种颗粒细胞条件培养液均可增加精子的顶体反应率,只是程度有所不同。提示在哺乳动物的精卵相遇时,随卵排出的颗粒细胞可能释放了某种因子,刺激了精子发生顶体反应而完成获能,是受精的关键步骤之一。     

Effects of altered epididymal sperm transit time on sperm quality

The epididymal sperm transit time seems to have an important role in the process of sperm maturation, and it seems that alterations to the transit can harm the process. The aim of the present work was to evaluate the influence of altered sperm transit time through the epididymis on sperm parameters and fertility of rats, as well as the role of testosterone in the alterations. Sprague–Dawley adult male rats were randomly assigned to four different groups and were treated for 12 days: (i) 10 μg/rat/day DES, to accelerate the transit; (ii) 6.25 mg/kg/day guanethidine sulphate, to delay the transit; (iii) same treatment as group 1, plus androgen supplementation; (iv) control animals received the vehicles. Guanethidine treatment delayed the sperm transit time through the epididymal cauda, provoking increased sperm reserves in this region. Animals exposed to DES showed an acceleration of sperm transit time in the epididymis, and consequently decreased sperm density in both epididymal regions, the caput-corpus and cauda, and diminished sperm motility. In both cases sperm production was not altered. Testosterone supplementation was able to restore the transit time to values close to normality, as they were higher than in the control rats. The same occurred in relation to sperm motility. Rats exposed to DES presented lower fertility after in utero artificial insemination using sperm collected from the proximal cauda epididymis. Therefore, it was concluded that the acceleration of rat sperm transit time appeared to harm normal sperm maturation, thus decreasing sperm quality and fertility capacity, in an androgen-dependent way.     

Effect of alpha-chlorohydrin on epididymal sperm and epididymal plasma in swine.

Investigation of the contraceptive mechanism of alpha-chlorohydrin was done by analyses of epididymal plasma and certain epididymal sperm characteristics after oral administration of 0, 5, 10 or 30 mg/kg, day of the drug to boars for 15 days. Water resorption in caput epididymidis was slightly decreased in all treatment groups. Sodium, potassium, chloride, glycerylphosphorylcholine levels, and seminal antigens in epididymal plasma were not altered significantly by 10 or 30 mg/kg of the drug. The boars on 5 mg/kg exhibited significantly elevated sodium, potassium, or chloride values in various segments. Motility was significantly lower on corpus and proximal cauda epididymal spermatozoa from alpha-chlorohydrin treated boars. Only boars receiving 30 mg/kg exhibited impaired sperm motility in the distal cauda. The movement of the cytoplasmic droplets to the distal position was retarded in boars on the two highest dose levels. The results suggest that the contraceptive effects of alpha-chlorohydrin in the boar is probably not mediated via an impaired epididymal function.