Presence and Distribution of Urocortin and its Receptors in the Epididymis of Alpaca (Vicugna pacos)

Urocortin 1 (UCN) is a 40‐amino acid peptide belonging to the corticotrophin‐releasing hormone (CRH) family. The biological effects of this peptide are modulated by binding two G‐coupled receptors named CRH receptor 1 (CRHR1) and CRH receptor 2 (CRHR2). CRHR2 has high affinity for UCN. The aim of the present study was to investigate the presence and distribution of UCN, CRHR1 and CRHR2 in the epididymis of the South America camelid Alpaca (Vicugna pacos) by Western blotting analysis and immunohistochemistry. Tissue extracts of the organ reacted with the anti‐UCN, anti‐CRHR1 and anti‐CRHR2 antibodies, recognizing in all the cases a single specific protein band. UCN‐ and CRHR2‐immunoreactivities (IRs) were found in the cytoplasm of the principal cells (PCs) of the caput epididymis. A prevalent supranuclear localization of granular‐shaped positive material was observed. CRHR1‐IR was observed in the fibromuscular stromal cells encircling the tubules and in the smooth musculature of the blood vessels throughout the three epididymal segments. In addition, in the cauda, CRHR1‐IR was observed in some apical epithelial cells (ACs) which were morphologically similar to apical mitochondria‐rich cells (AMRCs). These results suggest that UCN, CRHR1 and CRHR2 are expressed in the alpaca epididymis and that CRH‐related peptides might play multiple roles in maturation and storage of spermatozoa.     

Presence and Distribution of Urocortin and Corticotrophin‐Releasing Hormone Receptors in the Bovine Thyroid Gland

Urocortin (UCN), a 40 amino acid peptide, is a corticotrophin‐releasing hormone (CRH)‐related peptide. The biological actions of CRH family peptides are mediated via two types of G‐protein‐coupled receptors, CRH type 1 (CRHR1) and CRH type 2 (CRHR2). The aim of this study was to investigate the expression of UCN, CRHR1 and CRHR2 by immunoprecipitation, Western blot, immunohistochemistry and RT‐PCR in the bovine thyroid gland. Immunoprecipitation and Western blot analysis showed that tissue extracts reacted with the anti‐UCN, anti‐CRHR1 and anti‐CRHR2 antibodies. RT‐PCR experiments demonstrated that mRNAs of UCN, CRHR1 and CRHR2 were expressed. UCN immunoreactivity (IR) and CRHR2–IR were found in the thyroid follicular and parafollicular cells and CRHR1‐IR in the smooth muscle of the blood vessels. These results suggest that a regulatory system exists in the bovine thyroid gland based on UCN, CRHR1 and CRHR2 and that UCN plays a role in the regulation of thyroid physiological functions through an autocrine/paracrine mechanism.     

The presence of androgen receptors in the epididymis and prostate of the stallion and cryptorchid horse--a preliminary study

Distribution of androgen receptors (ARs) in the epididymal duct and prostate of three entire stallions and one bilaterally cryptorchid horse was studied immunohistochemically using a polyclonal rabbit antiserum against the ARs. In both the healthy stallions and the cryptorchid, the epithelial cells of the epididymides showed nuclear staining for ARs. The intensity of AR-staining in the principal cells of the epididymis was stronger than that of the basal cells. In the prostate, the glandular secretory cells were moderately stained whereas the basal cells expressed weak AR-staining. Immunostaining for ARs in the reproductive tissues of the cryptorchid horse was always stronger than in those of the stallions. Our results demonstrate for the first time the AR localisation to equine epididymal and prostatic cells, which are directly regulated by androgens.     

A light and scanning electron microscopic study of the epididymis active state of the endemic Mexican rodent Peromyscus winkelmanni (Carleton) (Rodentia: Muridae)

The macroscopic and microscopic anatomy of the epididymis of the sexually mature Peromyscus winkelmanni (carleton) was examined using light and scanning electron microscopy. The epididymis was divided into three regions: caput, corpus and cauda. The epididymal duct was lined with columnar and cubic epithelium with stereocilia and covered by a muscular connective tissue sheath. Capillaries appear to penetrate directly into the epithelium from the underlying connective tissue in the initial segment. The epididymal epithelium presents four cell types: principal, basal, apical and clear cells. Based on morphological differences (height of epithelial cells, length of the stereocilia, luminal area, larger diameter and spermatic index), the epididymis of P. winkelmanni, presents seven zones. The stereocilia of the epididymal ducts of zones I, II, IV and V are thick and tall, while in zone III they are thin and short. The stereocilia in zone VI are thin, while in zone VII they are short but thick. The secretory products observed in the lumen of the epididymal ducts have vesicular, granular and fibrous form in the seven zones. This study contributes to an understanding of the morphofunctional features of the epididymis in sperm maturation in a species that shows seasonal reproductive activity.     

The surface features of the epithelial lining of the ducts of the epididymis of the ostrich (Struthio camelus)

The luminal appearance of the various ducts of the epididymis of the ostrich was studied by scanning electron microscopy in tissues fixed by immersion in glutaraldehyde. The ductal types were similar to those previously described for some other species of birds. Numerous short microvilli, as well as a single cilium, projected from the apical surface of the rete testis cell. The ciliated cells of the efferent ductules projected tufts of cilia into the ductal lumen, while the non-ciliated cells bore short microvilli. The connecting and epididymal ducts were lined by a columnar cell type whose apical surface bore uniformly distributed microvilli and a single, centrally situated cilium. The spermatozoa found in all ducts of the epididymis bore a distal cytoplasmic droplet. This observation has implications for the maturational process in the ostrich spermatozoon in the epididymis. The surface features of the ducts, except for a few noteworthy differences, were generally similar to those previously described for the male domestic fowl, turkey and duck.     

Histological Characteristics of Adult Yak Epididymis in Different Breeding Seasons

To compare the histological changes of the adult yak's epididymis in different breeding seasons,six adult yak testis in breeding season and nine adult yak testis in breeding interval were collected for structure investigation by HE staining,Masson's and Gomori's histochemistry methods,and IPP (Image-Pro Plus) statistics method was used to quantitative statistics.The results showed that comparing with the adult yak in the breeding interval,the epididymis ducts of adult yak in the breeding season were covered with the columnar ciliated epithelium.The collagen and reticular fiber in cauda epididymis were obviously more abundant than caput and corpus epididymitis.And the thickness of columnar epithelium cells in caput and corpus epididymitis,the length of the cilia in caput,and also the internal and external lumen diameter of caput and corpus epididymitis were all significantly increased in the breeding season (P<0.05),but the external lumen diameter of the cauda epididymis had no significant differences (P>0.05).In conclusion,the research showed that the distribution of collagen and reticular fiber in adult yak's epididymis interstitial were similar,and they were more rich in cauda epididymis,which might relate to the capacity and the sperm transport;The changes of the epithelial thickness,the length of cilia,the internal and external lumen diameter were close related to the different breeding seasons,and it might be a common phenomenon in plateau mammals that the enlargement and reduction of the epididymal duct in different breeding seasons.     

不同繁殖季节成年牦牛附睾组织特征比较

为比较不同繁殖季节成年牦牛附睾组织结构特征变化,应用苏木精-曙红常规染色、Masson's和Gomori's特殊组织化学染色方法比较不同繁殖季节牦牛（6头繁殖期成年牦牛和9头繁殖间期成年牦牛）附睾的组织结构特点并用IPP图像分析软件进行定量分析。结果显示,与繁殖间期相比,繁殖期附睾尾间质胶原纤维和网状纤维较附睾头及附睾体明显增多;附睾头和附睾体柱状上皮厚度显著增加（P<0.05）,附睾头纤毛长度增加显著（P<0.05）;附睾头和附睾尾管腔内径及外径显著增高（P<0.05）;但是附睾尾管腔外径繁殖期与繁殖间期相比差异不显著（P>0.05）。本研究结果表明,成年牦牛附睾管外围网状纤维与胶原纤维分布一致,二者在附睾尾较为丰富,可能与其较强的收缩能力及精子运输有关;柱状纤毛上皮高度及纤毛长度、管腔内径与外径的变化与其所处的不同繁殖季节密切相关,附睾管腔的膨大和回缩亦可能是高原地区季节性繁殖的哺乳动物中一种普遍存在的现象。     

Immunolocalization of Aquaporin Water Channels in the Domestic Cat Male Genital Tract

Four different aquaporins (AQP1, 2, 5 and 9), integral membrane water channels that facilitate rapid passive movement of water, were immuno‐localized in the excurrent ducts collected from sexually mature cats during orchiectomy. Aquaporins 1, 2 and 9, were immuno‐localized at distinct levels, whereas AQP5 was undetectable all along the feline genital tract. No immunoreactivity was present at the level of the rete testis with any of the antibodies tested. In the efferent ducts, AQP1‐immunoreactivity was strongly evidenced at the apical surface of the non‐ciliated cells, and AQP9‐immunoreactivity was shown at the periphery of both ciliated and non‐ciliated cells. Aquaporins 2 was absent in the caput epididymidis, either in the efferent ducts or in the epididymal duct. Otherwise, AQP2 was increasingly localized at the adluminal surface of principal cells from the corpus to the cauda epididymidis and more weakly in the vas deferens epithelium. The supranuclear zone of the epididymal principal cells was AQP9‐immunoreactive throughout the duct, with the exclusion of the vacuolated sub‐region of the caput and with higher reaction intensity in the cauda region. AQP1 was present in the blood vessels all along the genital tract. AQP1 was expressed also in the smooth muscle layer of the vas deferens. The tested AQP molecules showed a different expression pattern in comparison with laboratory mammals, primates and the dog, unique other carnivore species studied to date. The present information is possibly useful in regard to the regional morphology of the feline epididymis and correlated functions, which are still a matter of debate.     

Localization of Oestrogen Receptors in the Epididymis During Sexual Maturation of the Domestic Cat

Oestrogens are involved in regulation of spermatogenesis and sperm maturation and are essential for male fertility. To study the role of oestrogens on epididymal function in the domestic cat, we analyzed the localization patterns of oestrogen receptors (ERs) within the epididymis of juvenile, pubertal and adults using immunohistochemistry. Cat epididymal tissues obtained during routine castrations were fixed in chilled Bouin's solution and processed for immunohistochemistry with ER-specific antibodies. For a certain receptor type, ER localization was influenced by donor age. In the juvenile epididymis, ERα was localized in the nuclei of epithelial cells of efferent ducts and undifferentiated epithelium of the ductus epididymis. During puberty, ERα localization in the undifferentiated epithelium of the epididymis shifted from the nuclei to the cytoplasm and plasma membrane. Oestrogen receptor-α level was highest in the pubertal and adult epididymis, especially within the cytoplasm and in plasma membranes of caput epithelial cells. This finding was suggestive of a role in fluid reabsorption within the efferent ducts and the epididymis. In corpus and cauda regions, ERα was less abundant, suggesting a minor role for oestrogens in sperm storage areas. Interestingly, localization of ERβ was neither influenced by age nor location within the epididymis and was ubiquitous throughout. Results demonstrate that oestrogen actions within the epididymis may be predominantly mediated through ERα during sexual maturation in the domestic cat.     

Ultrastructural study of the luminal surface of the ducts of the epididymis of gallinaceous birds

The various ducts of the epididymides of four gallinaceous birds, the turkey (Meleagris gallopavo), domestic fowl (Gallus gallus), guinea-fowl (Numida meleagris) and Japanese quail (Coturnix coturnix japonica) were studied at the scanning and transmission electron microscopy levels. The tissues were fixed either by immersion or vascular perfusion, for comparative purposes. Each duct system, save for a few details, presented similar morphological features in all species. The epithelial surface of the rete testis was regular and each cell bore a single cilium, as well as numerous, or in some parts, very few, short, regular microvilli. Each of the Types I and II non-ciliated cells of the proximal and efferent ducts displayed abundant, moderately long and regular microvilli, and a solitary cilium. The ciliated cells exhibited tufts of cilia. The Type III non-ciliated cell of the connecting and epididymal ducts exhibited a solitary cilium, and numerous microvilli which were intermediate in length between those of the rete testis and those of the efferent ducts. Vascular perfusion of the avian epididymal tissue was the superior method of fixation because it minimised the developments of fixation artefacts. Apocrine secretion did not appear to occur in the epididymis of these birds as the apical blebs of Types I, II and III cells, which have previously been reported, only manifest in this study in inadequately fixed tissues, and were therefore viewed as being artefacts. The present findings suggest that the current terminology, as applied to the avian epididymis, be retained.     

Immunolocalization of sex steroid receptors in the epididymis and ductus deferens of immature and mature Japanese Quail, Coturnix Japonica

The goal of this study was to determine whether in the Japanese quail the male genital tract contains receptors for progesterone, androgen and estrogen (PR, AR and ER, respectively), which have significant roles in reproductive functions, and whether their localization changes during sexual maturation. The epididymis and ductus deferens (middle and ampulla regions) of immature (approximately 30-day-old) and mature male Japanese quail were collected and frozen sections of them were immunostained for PR, AR and ER. The immunoreaction products for AR and PR were found in the nuclei of epithelial cells in the efferent ductules, epididymal duct, and the middle and ampulla regions of the ductus deferens of mature and immature birds. In the mature birds, the epithelial cells of the efferent ductules, epididymal duct, and the middle and ampulla regions of the ductus deferens were positive for ER, although some of the cells in the ductus deferens were negative. The epithelial cells of the ductules in the epididymis stained positive for ER, but the immunoreactions were negligible in the ductus deferens of immature birds. These results suggest that the epididymis and ductus deferens in quail possesses PR, AR and ER receptors. Each receptor is expressed before sexual maturation, although enhancement of ER expression may occur during maturation.     

Epithelial response to experimentally introduced intraluminal bacteria in the avian epididymal ducts

The response of the epithelial cells of the various ducts of the avian epididymis, whose function is poorly understood, to intraluminal bacteria was evaluated by the injection of an avirulent strain of Salmonella gallinarium into the RT for 24 h. Ultrastructurally, bacteria and invading mononuclear cells were present in the lumina of the RT, proximal efferent ducts (PED) and distal efferent ducts. However, only the non-ciliated (Type I) cells of the PED epithelium ingested bacteria from the lumen. Fragments of bacteria also occurred in several intercellular spaces in the epithelium of the PED. Some mononuclear cells also contained fragments of bacteria. Neither cell death in the various epithelia nor mononuclear infiltration of the periductal tissue occurred. Therefore, in addition to the established function of absorbing most of the testicular fluid entering the epididymis, the Type I cells also appear capable of recognising and removing foreign particulate matter from the epididymal through-flow in the proximal part of the epididymis.     

The Excurrent Ducts of the Testis of the Emu (Dromaius novaehollandiae) and Ostrich (Struthio camelus): Microstereology of the Epididymis and Immunohistochemistry of its Cytoskeletal Systems

The volumetric proportion of the various ducts of the epididymis of the emu and ostrich and the immunohistochemistry of actin microfilaments, as well as cytokeratin, desmin and vimentin intermediate filaments, were studied in the various ducts of the epididymis of the emu and ostrich. The volumetric proportions of various ducts, which are remarkably different from those of members of the Galloanserae monophyly, are as follows: the rete testis, 5.2 ± 1.4% for the emu and 2.4 ± 1.8% for the ostrich; efferent ducts, 14.2 ± 2.3% (emu) and 11.8 ± 1.8% (ostrich); epididymal duct unit, 25.8 ± 5.8% (emu) and 26.1 ± 4.1% (ostrich) and connective tissue and its content, 54.7 ± 5.8% (emu) and 60.0 ± 4.9% (ostrich). Unlike in mammals and members of the Galloanserae monophyly, only vimentin was immunohistochemically demonstrated in the rete testis epithelium of the emu, and none of the cytoskeletal protein elements in the ostrich rete testis. The epithelium of the efferent ducts of the emu co-expressed actin, cytokeratin and desmin in the non-ciliated type I cells, and vimentin in the ciliated cell component. The ostrich demonstrated only cytokeratin in this epithelium. The ratite epididymal duct unit is different from that of mammals in lacking actin (only weaky expression in the ostrich), desmin and cytokeratin, and a moderate/strong immunoexpression of vimentin in the basal cells and basal parts of the NC type III cell in the epididymal duct unit. Immunoexpression of the microfilaments and intermediate filaments varied between the two ratite birds, as has been demonstrated previously in birds of the Galloanserae monophyly, and in mammals.     

Ultrastructural study on junctional complexes of the excurrent duct epithelia in the epididymal region in the fowl.

Junctional complexes of the epithelia lining the rete testis, efferent ductules, connecting ductules and epididymal duct in the fowl were examined by transmission electron microscopy and by a tracer method using lanthanum nitrate. The junctional complexes were composed of tight junctions, adhering junctions and desmosomes. In the rete testis, one or two points of membrane fusion were observed at the tight junctions. In the efferent and connecting ductules and epididymal duct, the tight junctions consisted of a series of punctate membrane fusions. The adhering junctions and desmosomes showed no remarkable structural differences among these excurrent ducts. Vascularly infused lanthanum nitrate penetrated into the tight junctions of individual epithelia for variable distances, but was prevented from entering the lumen at the site of membrane fusion. These results suggest that the tight junctions can restrict the diffusion of materials via the paracellular route, and that they play an important role in maintaining a suitable fluid environment within the excurrent ducts.     

Histological studies on the regional postnatal differentiation of the epididymis in the ram.

The regional postnatal development of the epididymal duct was studied with histological technique in 22 lambs of the “Swedish Landrace” breed at intervals from 1 week to 18 weeks after birth. At one week, the whole epididymal duct had a simple low columnar epithelium. In the terminal segment the epithelium ecquired a structure similar to that in the adult epididymis at the age of about 6 weeks. Normal spermatozoa were not seen in the cauda epididymidis until the lambs were about 18 weeks old. In the middle segment, distal, intermediate and proximal parts, the epithelium increased gradually in height and reached the adult type at about 12, 15 and 18 weeks, respectively. At about 12 weeks of postnatal life, the epithelium of the initial segment increased rapidly in height, at the same time as a distinct lumen formed in the seminiferous tubules. As far as histological features were concerned, the initial segment showed the adult type when the lambs were about 18 weeks old. The presence of spermatozoa in the cauda epididymidis indicates that the lambs readied sexual maturity at this age. It was concluded that the postnatal differentiation of the ram epididymis starts in the terminal segment and then ascends through the middle and initial segments.     

Expression of aromatase and oestrogen receptors in reproductive tissues of the stallion and a single cryptorchid visualised by means of immunohistochemistry

Androgen metabolism may proceed to amplify the action of testosterone by its aromatisation to oestradiol. Recently, a growing body of evidence suggests a role of oestrogens in the male reproductive tract via their specific oestrogen receptors (ERs). In order to check whether androgens are converted to oestrogens in the testis, epididymis and prostate of the stallion, the expression of aromatase was visualised by means of immunohistochemistry. Moreover, to show the cellular targets for oestrogens the presence of oestrogen receptor alpha (ERalpha) and oestrogen receptor beta (ERbeta) was demonstrated in these tissues. Finally, to show whether naturally occurring cryptorchidism has any influence on the localisation of aromatase and distribution of ERs, the reproductive tissues of a single horse, bilaterally cryptorchid, were also taken for this study. The results demonstrated that aromatase and ERs are ubiquitously distributed throughout the male reproductive tract, what indicates a putative role of oestrogens in modulating the function of the reproductive tissues of the stallion. In the cryptorchid horse the increase in conversion of androgen to oestrogen was observed as manifested by aromatase overexpression. This is the first report showing the cellular site of oestrogen biosynthesis not only in the testis but also in the epididymis and prostate of sexually mature stallion and a single, adult cryptorchid.     

Immunolocalization of Androgen Receptor in the Boar Epididymis: the Effect of GnRH Agonist Deslorelin

Epididymides from nine crossbred male pigs [Polish Landrace × (Duroc × Pietrain)] (n = 3 per each group) were used in this study to show whether there are any differences between androgen receptor (AR) distribution along epididymal duct of a GnRH agonist deslorelin-treated boars when compared to the control tissues. The active agent was administered by way of a subcutaneous controlled-release implant containing 4.7 mg deslorelin at 91 or 147 days of age respectively. Boars from two experimental groups and the control group were slaughtered at 175 day of age. Immunolocalization was performed using a polyclonal rabbit antiserum against the AR. In control boars, strong staining for AR was detected in nuclei of the epithelial (principal and basal) and stromal cells, whereas in boars treated with deslorelin the staining was confined to the principal cell nuclei. In those treated for 84 days, AR-immunostaining was weak or the principal cells were negative for the AR. Irrespective of the time from deslorelin insertion all stromal cells were immunonegative. The results demonstrate for the first time the effect of deslorelin on the distribution of the AR in the three regions of the boar epididymis. It is likely that stromal cells are more sensitive than epithelial cells to the regulation of AR expression by androgen. The morphological and functional alterations along the epididymal duct and lack of spermatozoa within the lumen after deslorelin treatment indicate that a potent GnRH agonist is likely responsible for an impairment of the microenvironment created by epididymal cells for sperm maturation and their storage.     

性成熟前不同日龄伊拉兔睾丸和附睾形态学与组织学特征

【目的】探究不同日龄伊拉兔睾丸和附睾组织在性成熟前的变化规律,为其初情期及性成熟的判定提供组织学依据。【方法】将45只伊拉兔随机分为9组,每组5只,从30日龄开始每隔15日采集1组试验兔的睾丸及其附睾,运用形态学与组织解剖学方法对其生长发育规律进行研究分析。【结果】随着日龄的增加,睾丸指数、睾丸重、睾丸长径、睾丸短径及厚径等指标逐步增加,且150日龄时各指标均显著高于其他组（P＜0.05）;30、45、60日龄睾丸内生精小管排列稀疏,75、90、105日龄时睾丸间质成分逐渐增多,管腔逐步形成,120、135、150日龄时间质细胞进一步增生并成群分布,90日龄起出现圆形和长形未成型精子,120日龄的睾丸生精小管、附睾管腔中出现少量成型精子,150日龄时有大量精子密集分布于睾丸管腔内,且在120、135、150日龄时生精小管面积、上皮细胞厚度、支持细胞数均显著大于其他组（P＜0.05）;30日龄以上各组间质细胞个数在各组间差异不显著（P＞0.05）,但均显著高于30日龄;120、135、150日龄时附睾头、体、尾的直径均极显著高于其他组（P＜0.05）,而附睾头的柱状上皮厚度和纤毛长度则从105日龄起就显著高于30、45、60、75和90日龄组（P＜0.05）。【结论】伊拉兔睾丸和附睾随日龄增加同步发育,在120日龄时达到初情期,在150日龄时睾丸和附睾已发育成熟,基本达到性成熟。     

Seasonal changes in morphology and immunoreactivity of PDGF-A and its receptor PDGFR-α in the epididymis of wild ground squirrels (Citellus dauricus Brandt)

The platelet-derived growth factor (PDGF) system is expressed and can exert its biological role in the male reproductive system including the maintenance of morphological structure and function of the epididymis. The aim of this study was to clarify the relationship between the PDGF system and seasonal changes in morphology of the wild ground squirrel epididymis during the breeding and nonbreeding seasons. Hematoxylin-eosin (HE) staining was used to observe the epididymal morphology and histology. Immunohistochemistry and Western blotting were performed to detect the immunoreactivities of PDGF-A and B and PDGFR-α. Significant seasonal changes in epididymal morphology were observed in the breeding and nonbreeding seasons. The proportions of the three compartments (interstitial tissue, epithelium and lumen of the duct) revealed distinct variances. Strong immunostaining of PDGF-A was present in the myoid cell and on the sperm in the breeding season, whereas there was a faint signal in the myoid cell in the nonbreeding season. PDGFR-α was expressed in all cell types of the epithelium throughout the whole seasonal cycle, and immunostaining of PDGFR-α in the breeding season was significantly stronger compared with that of the nonbreeding season. PDGF-B was not detected in the epididymis of wild ground squirrels. These results suggested that seasonal morphological changes in epididymis were correlated with immunoreactivities of PDGF-A and its receptor PDGFR-α and that PDGF-A and PDGFR-α might function as paracrine, autocrine or apocrine factors in wild ground squirrels.