Immunohistochemical studies of the epididymal duct in Egyptian water buffalo (Bubalus bubalis)

Seasonal Variation of the Intraepithelial Gland in Camel Epididymis with Special Reference to Autophagosome

The key role of the epididymis is contributing to sperm storage, maturation, and survival. The epididymis of camel has a unique structure called the intraepithelial gland. The present work aimed to investigate the structure of the epididymal intraepithelial gland with special references to the seasonal variation. The samples were collected from the distal part of the corpus epididymes of completely healthy mature camels (Camelus dromedarius) in the breeding and nonbreeding seasons. Tomato lectin-positive material had been demonstrated within the epididymal spermatozoa. Here, we provide the first transmission electron microscopic study for the intraepithelial gland of camel epididymis detecting the autophagy during the nonbreeding season. The autophagosomes originated from the endoplasmic reticulum, surrounding mitochondria, and located mainly next to the basement membrane. This location is probably valuable for subsequent passing of their contents into the interstitium for possible recycling. The histochemical and ultrastructural characteristics of the gland in the breeding season indicated a hyperactive secretory microenvironment enriched with the glycoprotein-producing machinery, which could be controlled by androgens. The present data suggest that the camel intraepithelial gland has a significant impact on the reproductive activity through their secretory microenvironment during the breeding season. Moreover, it recycles the unused organelles or proteins for reuse or to supply energy under stress conditions in the nonbreeding season.

Vascular endothelial growth factor (VEGF-A) and fibroblast growth factor (FGF-2) as potential regulators of seasonal reproductive processes in male European bison (Bison bonasus, Linnaeus 1758)

Growth factors: vascular endothelial growth factor A (VEGF-A) and fibroblast growth factor (FGF-2) were reported to affect normal physiological reproductive processes in human, domestic and free living animals. Moreover, some reports suggest that VEGF-A and FGF-2 may be directly involved in the control of the annual reproductive cycle of seasonally breeding animals but detailed knowledge is still missing. Our study aimed to demonstrate the expression of mRNA and protein for both factors in the tissues of testis and epididymis (caput, corpus, cauda) at different periods of the year (March, June, November, December) in European bison as a model of seasonally breeding animal. Results suggest, that VEGF-A expression was more pronounced in testis than in epididymis and the highest expression was noted in December and June. Surprisingly, the highest protein accumulation was observed in June at the same level in all tissues analyzed. On the other hand, the highest FGF-2 mRNA expression was noted in testis in June and in epididymis in March. However, no differences in protein expression of FGF-2 were found between analyzed groups. The results indicate that both factors are necessary for proper functioning of the reproductive system and their levels differ seasonally. Perhaps, it is linked to increased need of these factors in the testis as well as epididymis during preparation for the reproductive functions. Moreover, VEGF-A and FGF-2 not only may regulate reproductive functions by affecting vascularization and cell nutrition, but it also may be possible that they possess protective functions by stabilizing the reproductive cells. Therefore, obtained results provide new insight into mechanisms underlying seasonal breeding of the male European bison.

The effects of flutamide on cell-cell junctions in the testis, epididymis, and prostate

In this review, we summarize recent findings on the effect of the anti-androgen flutamide on cell-cell junctions in the male reproductive system. We outline developmental aspects of flutamide action on the testis, epididymis, and prostate, and describe changes in junction protein expression and organization of junctional complexes in the adult boar following prenatal and postnatal exposure. We also discuss findings on the mechanisms by which flutamide induces alterations in cell-cell junctions in reproductive tissues of adult males, with special emphasis on cytoplasmic effects. Based on the results from in vivo and in vitro studies in the rat, we propose that flutamide affects the expression of junction proteins and junction complex structure not only by inhibiting androgen receptor activity, but equally important by modulating protein kinase-dependent signaling in testicular cells. Additionally, results from studies on prostate cancer cell lines point to a role for the cellular molecular outfit in response to flutamide.

Seasonal immunohistochemical reactivity of S-100 and α-smooth muscle actin proteins in the epididymis of dromedary camel, Camelus dromedarius

The S-100 and alpha smooth muscle actin (α-SMA) proteins have been localised in epididymal tissue of several mammalian species, but there have been no data for a seasonal work in camel. The aim of this study was to investigate the immunoreactivities of S-100 and α-SMA proteins in the epididymis of dromedary camel during breeding and nonbreeding seasons. The immunopositive signals for both proteins were observed in different regions of camel epididymis. S-100-immunopositive signals were noted in both the epididymal epithelium and the intertubular connective tissue, while α-SMA signals were confined to the intertubular connective tissue, especially in the peritubular smooth muscle coat and the blood vessels. This study showed an increase in the intensity of S-100 and α-SMA immunoreactions during the breeding season in different regions of camel epididymis than that seen in the nonbreeding season. In conclusion, epididymis might be considered as a source of S-100 and α-SMA proteins in the camel and the secretion of these proteins showed distinct seasonal variations. Further, S-100 and α-SMA may affect the structural and physiological states of the epididymal duct.

Histological and morphometric study of the epididymus of Chinchilla lanigera Grey under controlled conditions in captivity

Chinchilla lanigera, native to the Andean Mountains of Perú, Chile, Bolivia and Argentina, is a specimen of great economic importance because of its fur. In mammals, spermatozoa originate in testes and are transported to the epididymis, where they undergo morphological and biochemical modifications known as sperm maturation, a basic step in the acquisition of their fertilizing ability. The aim of this work is the macroscopic and microscopic analysis of the epididymis of Chinchilla lanigera Grey and its sectorization based on a histomorphological study. The epididymis presents a clear segmentation into four regions: initial segment, caput, corpus and cauda. The epithelium lining the seminiferous tubules is pseudostratified, with principal cells with stereocilia and basal, clear, apical, narrow and halo cells. The histological analysis showed that principal and basal cells are the prevailing populations in all regions, also revealing narrow cells and the absence of clear cells in the initial segment. Each segment presents its different histological and morphometric characteristics, which supports the idea of the specific behaviour of each region, giving a segment-specific character to the process of sperm maturation in this species. No significant differences were found in the morphometric measurements or in the histological evaluation of the epididymis of samples collected in April and October. The fact that no differences were found between the samples collected during the two periods when the reproductive ability in nature is different suggests the importance of external factors in the control of the reproductive cycle of Chinchilla lanigera.

Localization of S-100 proteins in the testis and epididymis of poultry and rabbits

The present investigation was conducted to demonstrate S-100 protein in the testis and epididymis of adult chickens, Sudani ducks, pigeons, and rabbits. This study may represent the first indication for the presence of S-100 in the male reproductive organs of these species and might therefore serve as a milestone for further reports. In the testis of chickens, pigeons and rabbits, intense S-100 was seen in Sertoli cells. S-100 was also seen in the endothelial lining of blood vessels in rabbit testis. On the contrary, no S-100 reaction was detected in the Sertoli cells of Sudani ducks. In epididymis, the localization of S-100 had varied according to species studied; it was seen in the basal cells (BC) of epididymal duct in duck, non-ciliated cells of the distal efferent ductules in pigeons and ciliated cells of the efferent ductules and BC of rabbit epididymis. Conversely, S-100 specific staining was not detected in the epithelial lining of the rooster and pigeon epididymal duct as well as the principal cells of the rabbit epididymis. In conclusion, the distribution of the S-100 proteins in the testis and epididymis might point out to its roles in the male reproduction.

Prenatal development of the bovine epididymis: light microscopical, glycohistochemical and immunohistochemical studies

Prenatal development of the epididymis was studied in bovine fetuses ranging from 10 to 90cm crown-rump length (CRL) (75-285 pcd). The studies aimed to apply both glycohistochemistry and immunohistochemistry for the detection of the differentiation of the developing prenatal epididymis. Both conventional histological and histochemical techniques were applied on paraffin sections of the epididymis from different fetal stages. Establishment of the urogenital junction between the extra-testicular rete testis and the mesonephric duct, via the growing efferent ductules (ductuli efferentes) was first evident in fetuses with 10cm CRL. At the fetal age of 110 pcd (24cm CRL), the mesonephric duct began to lengthen and coil forming three distinct regions (caput, corpus and cauda). In addition to the macroscopical modifications in the extra-testicular excurrent duct system, histological differentiation involved both the tubular epithelial and the peritubular mesenchymal cells. The epithelium lining the efferent ductules was differentiated into ciliated and non-ciliated columnar cells. The simple epithelium of the epididymal duct increased in height and developed stereocilia on the apical surface. Additionally, some basal cells first appeared at 185 pcd (56cm CRL), within the epithelium lining the cauda only. Lectin histochemistry (WGA, PNA, GSA-I) showed early immunostaining in epithelium of the efferent ductules and in peritubular mesenchymal structures. Immunoreactivity for different proteins (S-100, fibroblast growth factor-1 and factor-2, angiotensin converting enzyme, laminin, alpha-smooth muscle actin) was evident, both in the epithelial and in the peritubular mesenchymal cells as early as at 75 pcd. On the basis of our histochemical observations, we conclude that both glycohistochemistry and immunohistochemistry are useful tools to demonstrate that the differentiation in the peritubular structures and efferent ductular epithelium begins earlier than other components.

Comparative morphometric and glycohistochemical studies on the epididymal duct in the donkey (Equus asinus) and dromedary camel (Camelus dromedarius)

The present study was undertaken to compare morphometric and glycohistochemical differences in the epididymal duct of the donkey and the dromedary camel. Paraffin-embedded sections from the different regions of the duct (caput, corpus and cauda) of both species were stained conventionally for general histology and histomorphometry and also with fluorescein isothiocyanate (FITC) conjugated lectins for glycohistochemical mapping. Morphometric data (means ± SE) showed that the luminal diameter was widest (1029.76 ± 15.04 μm) in the donkey cauda and narrowest (179.80 ± 3.27 μm) in the camel corpus. The thickness of the peritubular muscle coat had the highest (74.32 ± 1.85 μm) and the lowest (24.32 ± 0.74 μm) values in the donkey cauda and corpus respectively. The greatest (94.44 ± 2.08 μm) and the least (21.48 ± 0.66 μm) values of epithelial height were reported respectively in the camel caput and in the donkey cauda. The length of stereocilia of principal cells in the camel was greatest (21.88 ± 0.57 μm) and lowest (6.68 ± 0.28 μm) in the caput and cauda. Binding sites for only six out of eight lectins could be found. The distribution pattern of binding sites of different lectins showed significant variations in both a species-specific and also region-specific manner. Distinct labeling was found in the Golgi zone, apical cytoplasm and on stereocilia of principal cells in the camel (WGA and DBA) and donkey (DBA) caput region, while other lectins exhibited variable reactivity in the other regions in both species. The basal cells showed variable binding to most of the lectins, however, they displayed distinct binding to WGA and PSA throughout the duct in camel and donkey respectively. In conclusion, both morphometric and glycohistochemical findings displayed regional species-specific and potentially functional relevant characteristics.

Immunohistochemical studies on the poll gland of the dromedary camel (Camelus dromedarius) during the rutting season

The poll glands are subcutaneous exocrine glands located on the back of the neck behind the ears in male camels. The function of poll glands is not well known, though they are thought to play a role during the rutting season. The presence, location and degree of immunolocalization of microfilaments and intermediate filament systems: actin and cytokeratins (Cks) and also S100 protein were studied in the poll glands in sexually mature one-humped camels during the rutting season. These proteins were variably expressed between the epithelia, perialveolar, interalveolar tissue and the periductal tissue. Strong α-smooth muscle actin (α-SMA) immunoreactivity (IR) was displayed by the perialveolar myoepithelial cells, periductal and vascular smooth muscle cells (SMCs), but not in the epithelial cells. Cytokeratin (Ck)-IR was strong in the epithelial lining of the secretory alveoli and excretory ducts, however, the apical blebs of the secretory cells were almost negative. Weak to moderate Ck-IR was observed in the perialveolar myoepithelial cells, but not in the interalveolar tissue or endothelial cells. S100 protein was expressed variably in the epithelial lining of the secretory alveoli. S100-IR was more obvious in the supranuclear region and the apical blebs. Variable reaction was observed in the perialveolar myoepithelial cells, periductal and interductal tissue and endothelial cells.

Dicer1 ablation in the mouse epididymis causes dedifferentiation of the epithelium and imbalance in sex steroid signaling

Background

The postnatal development of the epididymis is a complex process that results in a highly differentiated epithelium, divided into several segments. Recent studies indicate a role for RNA interference (RNAi) in the development of the epididymis, however, the actual requirement for RNAi has remained elusive. Here, we present the first evidence of a direct need for RNAi in the differentiation of the epididymal epithelium.

Methodology/Principal Findings

By utilizing the Cre-LoxP system we have generated a conditional knock-out of Dicer1 in the two most proximal segments of the mouse epididymis. Recombination of Dicer1, catalyzed by Defb41^iCre/wt, took place before puberty, starting from 12 days postpartum. Shortly thereafter, downregulation of the expression of two genes specific for the most proximal epididymis (lipocalin 8 and cystatin 8) was observed. Following this, segment development continued until week 5 at which age the epithelium started to regress back to an undifferentiated state. The dedifferentiated epithelium also showed an increase in estrogen receptor 1 expression while the expression of androgen receptor and its target genes; glutathione peroxidase 5, lipocalin 5 and cysteine-rich secretory protein 1 was downregulated, indicating imbalanced sex steroid signaling.

Conclusions/Significance

At the time of the final epididymal development, Dicer1 acts as a regulator of signaling pathways essential for maintaining epithelial cell differentiation.

Histological and immunohistochemical studies on the epididymal duct in the dromedary camel (Camelus dromedarius)

This study was conducted to underscore the spatial distribution of some biologically active proteins within the epididymal duct in the dromedary camel. Paraffin-embedded sections from different regions of epididymis were stained by conventional histological techniques and by immunohistochemistry. A battery of primary antibodies against six proteins (S100, alpha smooth muscle actin [α-SMA], connexin-43 [Cx43], galactosyltransferase [GalTase], angiotensin converting enzyme [ACE], and vascular endothelial growth factor [VEGF]) were used. The epididymal epithelium consisted of five cell populations: principal, basal, apical, dark, and halo cells. The histochemical findings indicated the absence of binding sites for VEGF and Cx43. The principal cells (PCs) showed variable immunoreactivity (IR) for ACE, S100, and GalTase throughout the whole length of the duct. The apical surfaces of most PCs (at the caput) and some PCs (at the corpus) exhibited intense ACE-IR, whereas those at the cauda displayed alternating negative and strong immunostaining. Similarly, moderate S100-IR was found in cytoplasm and nuclei of all PCs at the caput, few PCs at the corpus, and several PCs alternating with negative PCs at the cauda. In contrast, only some PCs showed weak to strong GalTase-IR in different regions. Apart from negative to weak positive S100-IR, basal cells failed to show IR for all other proteins. Apical cells displayed strong IR for ACE, S100, and GalTase with some regional differences. The peritubular and vascular smooth muscle cells revealed strong α-SMA-IR in all regions. In conclusion, the spatial distribution of different proteins in camel epididymis showed similarities and differences to other mammalian species. The region-specific topographic distribution of different proteins and cell types might indicate that the caput and cauda are metabolically more active than that of the corpus.

Connexins and pannexins: Coordinating cellular communication in the testis and epididymis

Gap junctions and connexins are critical for coordinating cellular functions in complex epithelia. In recent years there has been increased interest in understanding the regulation and function of gap junctions in both the testis and epididymis. Studies in transgenic mice in which connexin 43 (Cx43) is mutated or is knocked down only in Sertoli cells have demonstrated the essential role of Cx43 in spermatogenesis and differentiation of Sertoli cells. In the epididymis developmental studies have shown a role for numerous connexins in the differentiation of epithelial cells and communication between the basal cells and both principal and clear cells. In both tissues several factors, such thyroid hormones and androgens, are important in regulating expression and function of connexins. Pannexins, which form cellular channels but are structurally similar to gap junction proteins, have been identified in both testis and epididymis and, in the epididymis, are regulated by androgens. The objective of this review is to summarize the advances that have been made on the role and regulation of connexins and pannexins in the testis and epididymis and their implication in spermatogenesis and sperm maturation.

Morphological and functional alterations in adult boar epididymis: Effects of prenatal and postnatal administration of flutamide

Background

The dynamic cross-talk between epididymal cells is hormonally regulated and, in part, through direct cell-to-cell interactions. To date, no information is available regarding possible impact of anti-androgens on the proteins involved in the gap junctional communication within the boar epididymis. Thus, a question arised whether prenatal or postnatal exposure to an anti-androgen flutamide alters the expression of gap junction protein - connexin43 (Cx43) and androgen receptor (AR) expression in the caput, corpus and cauda epididymis and leads to delayed effects on morphology and function of adult pig epididymis.

Methods

First two experimental groups received flutamide prenatally on gestational days 20-28 and 80-88 (GD20 and GD80) and further two groups were exposed to flutamide postanatally on days 2-10 and 90-98 after birth (PD2 and PD90). Epididymides were collected from adult boars. Routine histology was performed using hematoxylin-eosin staining. The expression of Cx43 and AR were analyzed using immunohistochemistry and Western blotting. Both analyses were supported by quantitative approaches to demonstrate the variations of the expression levels following the treatment. Apoptotic cells were identified using TUNEL assay.

Results

Histological examination revealed differences in epididymal morphology of flutamide-exposed boars when compared to controls. Scarce spermatic content were seen within the corpus and cauda lumina of GD20, PD2 and PD90 groups. Concomitantly, frequency of epididymal cell apoptosis was significantly higher (p < 0.05) after exposure to flutamide at GD20. Moreover, in GD20, PD2, and PD90 groups, significantly lower AR expression (p < 0.05) was found in the principal and basal cells of the corpus and cauda regions, while in the stromal cells AR expression was significantly reduced (p < 0.05) along the epididymal duct. Concomitantly, a decrease in Cx43 expression (p < 0.05) was noticed in the stromal cells of the cauda region of GD20 and PD2 groups. This indicates high sensitivity of the stromal cells to androgen withdrawal.

Conclusions

The region-specific alterations in the epididymis morphology and scarce spermatic content within the lumina of the corpus and cauda indicate that flutamide can induce delayed effects on the epididymal function of the adult boar by decrease in AR protein levels that results in altered androgen signaling. This may cause disturbances in androgen-dependent processes including Cx43 (de)regulation, however, we can not exclude the possibility that in response to flutamide decreased Cx43 expression may represent one mechanism responsible for functional disturbance of the boar epididymis.