Morphological and glycohistochemical studies on the epididymal region of the Sudani duck (Cairina moschata)

In this study, the epididymal region of the Sudani duck was investigated using histological and lectin histochemical methods. Morphologically, the epididymal region of the Sudani duck is composed of extratesticular rete testis, proximal and distal efferent ductules, a short connecting duct, and epididymal ducts. Morphometric analysis of the epididymal region of Sudani duck revealed that the efferent ductules predominate in relation to the epididymal ducts. The distribution of sugar moieties within the epididymal region of the Sudani duck was investigated using ten different fluorescein isothiocyanate (FITC) conjugated lectins. In the rete testis epithelium, only PHA-L showed a positive reaction. Efferent ductules in contrary exhibited a wide range of lectin affinity whereas six positive lectins (Con A, LCA, PNA, WGA, PHA-L, PHA-E) were observed. In the connecting and epididymal ducts, four lectins (Con A, WGA, PHA-L, PHA-E) were also detected. GSA-I, UEA-I, and LTA were at all not evident in the epididymal region of the Sudani duck. In conclusion, the correlation between the large areas of the epididymal region occupied by the efferent ductules and the wide range of sugar affinity of this portion may confirm the speculation that efferent ductules might be the primary site of fluid reabsorption in the epididymal region of Sudani duck.     

Active spermiophagy in the initial part of the proximal efferent duct of the epididymis of normal domestic fowl (Gallus domesticus)

In a study of the absorptive activities of the excurrent ducts of the testis of birds, six adult cocks of the Ovambo breed of domestic fowl were deeply anaesthetised and intravascularly perfused with buffered 3 per cent glutaraldehyde. Epididymal tissue was prepared conventionally for electron microscopy. In favourable sections in three of these birds avid ingestion of spermatozoa was revealed in the non-ciliated (Type I) cells of the epithelial lining of the initial part of the proximal efferent duct, at and a little beyond its junction with the rete testis. No obvious defects were detected in luminal spermatozoa. The testicular excurrent ducts were neither distended nor obstructed, and mononuclear cell mobilisation was absent in both the ductal and periductal tissue. The significance of this observation with regard to the specific segment of the efferent duct system involved and how certain spermatozoa are identified for elimination from the duct lumen, must await precise studies.     

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.     

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 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 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.     

Effects of ligation of the ductus deferens on the fowl epididymal region

The effects of ligation of the ductus deferens on the epididymis in the fowl were studied histochemically and immunohistochemically to reveal the mechanisms of sperm disposal. At one week post-ligation, the lumina of the rete testes (RT) and the efferent ductules (ED) were distended and filled with densely accumulated spermatozoa. Macrophages and foreign-body giant cells were aggregated in and around the accumulations. The epithelium regressed in the initial portion of the RT with the invasion of fibroblasts and heterophiles into the lumen. The other part of the epithelium was penetrated by many spermatozoa. Numerous lymphocytes and plasma cells infiltrated into the interstitium. At 4 weeks, larger number of spermatozoa agglutinated in the lumen, and large masses of foamy cells and proliferated connective tissue protruded into the lumen. At 8 weeks, large masses of foamy cells were noted. The connecting ductules or the epididymal duct showed no marked changes after ligation. The epithelium of the ED showed weaker or no acid phosphatase activity after ligation. Immunoglobulin G-containing cells increased in number in the interstitium. These results showed that ligation of the ductus deferens in the fowl causes granuloma in the RT and ED, and that epithelial cells, macrophages and granuloma are engaged in the removal of spermatozoa. The participation of antibody is suggested in the sperm disposal processes.     

雄性雏鸵鸟生殖器官的形态学研究

为了探明雄性雏鸵鸟生殖器官的形态学特点,采用石蜡切片和HE染色技术,对6羽45日龄雄性非洲雏鸵鸟的生殖器官进行了研究,并与家禽的相关结构进行了比较。在光镜下观察了雄雏鸟生殖器官的形态结构,结果表明:(1)鸵鸟睾丸没有睾丸纵隔和睾丸小叶,曲精小管中精原细胞排列紧密且整齐,睾丸间质较少;(2)附睾由睾丸网、输出小管和附睾管组成;(3)输精管管壁由黏膜、肌层和外膜3层组成;(4)阴茎由2个圆形的纤维性淋巴体、淋巴间隙和微血管共同构成。     

Immunohistochemical demonstration of myoid cells in the testis and its excurrent ducts in the domestic fowl

(1) Immunohistochemical methods and three antibodies (against actin, desmin and smooth muscle actin) were used to demonstrate the myoid cells in the domestic fowl testis and its excurrent ducts. (2) A positive reaction to actin, smooth muscle actin and desmin was found in the myoid cells of peritubular tissue of the testis and in rete testis, ductuli efferentes and ductus epididymidis. (3) In the testis myoid-reactive cells form a single layer. In the rete testis, ductuli efferentes and the ductus epididymidis reactive myoid cells form a main component of the stroma. (4) Positive reaction to actin, smooth muscle actin and desmin was also observed in the myoid cells of the tunica albuginea and in the wall of blood vessels in the testis and epididymis, indicating a contractile function for the testicular capsule.     

A Surgical Approach to Collect Testicular Fluid from the Extratesticular Rete Testis of the Pony

A surgical technique was developed to collect testicular fluid from the extratesticular rete testis of the pony stallion. A cannula was inserted through an incision in the visceral vaginal tunic following ligation of the efferent ductules. The cannula was sutured in place in the extratesticular rete testis. The other end of the cannula was exteriorized and inserted into a plastic collection receptacle fastened to the scrotum. Testicular fluid was collected for 12 to 36 hours at a rate of 1.07 ± 0.8 ml/hr. Sperm clots in the proximal end of the cannulas were responsible for the cessation of drainage.     

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.     

Morphology and innervation pattern of the feline urogenital junction

The feline urogenital junction is situated between the extratesticular rete and the spacious initial segments of the efferent ductules. The rete epithelium is cuboidal to low columnar. The rete cells forming the junction rest on a wavy basal lamina, display deep mutual invaginations, possess central nuclei with several infoldings and form a distinct border with the columnar epithelial cells of the initial segments of the ductuli efferentes. The epithelium of the initial segments is composed of ciliated cells and non-ciliated principal cells. The latter are the dominating type and characterized by an apical brush-border and a supranuclear endocytotic apparatus. The stroma of the extratesticular rete contains an abundance of collagen whereas contractile cells are here generally absent. In contrast, the initial segments of the efferent ductules are surrounded by elastic fibres and a layer of contractile cells. All nerves for the feline urogenital junction come from the nervus spermaticus superior. In the epididymal head, small nerve bundles deviate into the septa between the ductules. Single fibres establish a dense network within the muscular coat of the ductuli. At the transition to the extratesticular rete, this network ends abruptly. Nerve fibres in the confines of the rete are associated with blood vessels or proceed to the testicular interior, but establish no relationships with the rete epithelium or the myofibroblasts of the mediastinum. The nervous network in the walls of the efferent ductules and their initial segments is not only composed of sympathetic but also parasympathetic, non-myelinated fibres. Particularly noteworthy is the abundance of calcitonin gene-related peptide (CGRP)- and substance P (SP)-containing axons around the initial segments. Both neuroproteins are consistent markers for sensory neurones. Taken together, it can be assumed that the entry of seminal fluid and spermatozoa into the efferent ductules is controlled by a regulatory nervous chain provided with afferent and efferent components.     

Seasonal and Ageing‐Depending Changes of Aquaporins 1 and 9 Expression in the Genital Tract of Buffalo Bulls (Bubalus bubalis)

The presence of Aquaporins 1 (AQP1) and 9 (AQP9), integral membrane water channels that facilitate rapid passive movement of water and solutes, was immunohistochemically detected in the excurrent ducts collected from sexually mature buffalo bulls of proven fertility during the mating (late autumn–winter) and non‐mating (late spring to the beginning of autumn) seasons. Furthermore, the research was performed also on the epididymal cauda of a senile buffalo bull with inactive testis. Aquaporins 1 and 9 were immunolocalized at distinct levels. In the efferent ducts, AQP1 immunoreactivity was strongly evidenced at the apical surface of the non‐ciliated cells and weakly along the basal membrane of the epithelial cells. The latter reactivity disappeared during the non‐mating season. No AQP1 immunoreactivity was detected in the epithelium of epididymis and vas deferens, whereas AQP1 was expressed in the smooth muscle layer of the vas deferens. Aquaporin 1 was present in the blood vessels and in small nerve bundles all along the genital tract. The supranuclear zone of the epididymal principal cells was AQP9 immunoreactive, limited to the corpus and cauda regions, and vas deferens. The samples collected in the two reproductive seasons showed a weaker AQP9 immunoreactivity during the non‐mating season. A typical AQP9 immunoreactivity was noticed in the old buffalo examined. The tested AQP molecules showed a different expression pattern in comparison with laboratory mammals, primates, equine, dog and cat. In addition, seasonal differences were noticed which are possibly useful in regard to the comprehension of the morphophysiology of reproduction in the bubaline species, which are still a matter of debate.     

Expression of Occludin in Testis and Epididymis of Wild Rabbits, Lepus sinensis coreanus

Tight junctions (TJs) in inter-Sertoli junctional areas and epididymal epithelia build up the blood–testis barrier (BTB) and the blood–epididymal barrier (BEB), respectively. In this study, the expression of occludin, an integral member of the TJs, was examined in testis and different regions of epididymis of Lepus sinensis coreanus , an Korean wild rabbit species. In testis, intense occludin immunoreactivity was found in the basally located inter-Sertoli junctional area together with diffused immunoreactivity of occludin in the cytoplasm of Sertoli cells. It can be suggested that occludin is one of the robust elements of BTB in seminiferous tubules of rabbit testis. In proximal and distal caput epididymis, occludin immunoreactivity was found in the lateral as well as apical contacts of epithelial cells. In corpus epididymis, intense occludin immunoreactivity was found in the basolateral as well as apical contacts of epithelial cells together with cytoplasmic signal. In cauda epididymis, occludin immunoreactivity in luminal epithelia was relatively strong but largely found in the cytoplasm. This suggests that intriguing regulatory mechanisms differentially recruit occludin to the TJ in the different regions of epididymal epithelia. The differences in the subcellular localization as well as expression levels of occludin among the epididymal segments may reflect differential paracellular permeability of epithelia along the epididymal tubules and be correlated with sperm maturation in rabbit. In Western blot, a major form of occludin was MW 62 kDa together with small fragments of MW 34–39 kDa in testis and epididymis, suggesting the peptide cleavage of occludin. This is the first report on the molecular nature of TJs in a wild rabbit testis and epididymis.     

Long-term vasoligation in the domestic fowl (Gallus domesticus)

The effects of long-term (14 months) unilateral vasoligation on the tests and their excurrent ducts of the domestic fowl were studied histologically and ultrastructurally. Severe testicular degeneration and epididymal atrophy were observed in the ipsilateral organs while the contralateral control organs were normal. Massive macrophage activity was observed in the epididymal regions and to a lesser extent in some severely degenerated seminiferous tubules. Several granulomata occurred in the epididymal regions and the ducti deferentes, and most were resorbed or were undergoing resorption at the time of examination.     

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.     

Teaching Developmental Anatomy of the Genital System to VM1 Students at the University of Missouri-Columbia, USA

Developmental anatomy is integrated with gross anatomy. It consists of 12 lectures and is divided into body systems. The development of each system is correlated to its adult structures and species differences. The urinary and genital systems are developmentally and anatomically associated and originate together from the intermediate mesoderm. The urethra forms from the distal part of the urogenital sinus. Starting with the gonadogenesis, and continuing with the duct systems and external genitalia, the lectures are focused on the male and then on the female structures. At the end, the anomalies of the genital organs are exposed in detail, with suggestions for students, specialists and breeders to prevent and treat teratological conditions. The gonadogenesis is first presented in the indifferent stage. The differential stage is explained for the testis and then for the ovary. The genital duct system is exposed in the indifferent stage. The differential stage for the male includes the formation of the efferent ductules, the epididymal duct and the ductus deferens, while in the female, the focus is on the formation of the uterine tubes, uterus (including the horns, the body and the cervix), and the vagina. The indifferent stage of external genitalia is a complex stage, which originates from the mesodermal swellings adjacent to the cloacal membrane. In the male, the differential stage includes the formation of penis and penile urethra. In the female the genital tubercle forms the clitoris, the urethral folds form the labia, while the genital swellings degenerate. The hermaphroditism, gonadal dysplasia, the cryptorchidism, the persistent vestigial structures, and the penischisis (hypospadias and epispadias) as anomalies of the genital system conclude the lecture.     

The mammalian rete ovarii: a literature review

The rete ovarii is the homologue of the rete testis. It develops from cells of mesonephric origin which immigrate into the developing gonad of the embryo. The mature form of the rete ovarii is generally found to be groups of anastomosing tubules lined by cuboidal or columnar epithelium. These tubules are usually located in the hilus of the ovary, but may extend through the medulla or be isolated in the mesovarium adjacent to the hilus. The rete is often continuous with the transverse ductules through which it contacts the longitudinal duct of the epoophoron. The rete ovarii is important in the control of meiosis in the maturing ovary. Cells of the rete ovarii differentiate to form granulosa cells as well. The rete is also credited with secretory capability, a hypothesis supported by the observation of secretory material in the lumina of the rete tubules in several species. Cysts have been observed in the rete ovarii of several species. The rete ovarii of the adult does not appear to be a functionless vestige as has been previously reported.     

Scanning electron and light microscopic studies of the surface epithelium of the rete testis and epididymis of the boar. I. Rete testis and efferent ducts

The use of the scanning electron microscope gave a three dimensional representation of the epithelial surface. Additionally, light microscopy revealed the representative structure of the epithelium. The rete testis showed a single layer of cubic epithelial cells. Short and dense microvilli were found on the surface. Sporadically a single, cilia-like structure was recognized. An extratesticular rete testis was identified. The flowing transition of the epithelium between the rete testis and the efferent ductuli occurred at different levels, so that both kinds of epithelial structures were recognized in the same area. The efferent ductuli were composed of a single columnar epithelium consisting of two cell types, principal cells and ciliated cells. The ciliated cells were recognized by their cilia protruding into the lumen. The principal cells showed microvilli on their surface and bleblike apical protrusions which erupt into the lumen.