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

Role of the testicular capsule in seasonal modulation of the testis

While the seasonal testicular cycle has been well studied regarding internal components, no attention has been given to the testicular capsule (tunica albuginea and tunica serosa). This study elucidated the structure-function modulations of intra-testicular functions by its capsule in the finch red munia (Amandava amandava) during the annual testicular cycle. The birds were studied during breeding (preparatory and breeding) and nonbreeding (regressive and quiescent) reproductive phases using hematoxylin-eosin and acridine orange-ethidium bromide capsule staining, hormonal ELISA (LH and testosterone) and immunohistochemical expression of neuropeptides (GnRH, GnIH) and androgen receptor (AR). The thickness of the tunica albuginea was significantly increased with multiple myoid layers during the nonbreeding phases (p < 0.05). The thickness of the tunica serosa was not altered, although characteristics and distribution of squamous cells showed significant seasonal alterations. Immunoreactive (-ir) AR and GnIH cells were differentially localized on both layers of the capsule. Strong AR-ir cells on tunica serosa during breeding phases showed increased expression of the receptor; a significant increase in plasma LH and testosterone was also observed during the breeding cycle (p < 0.01). Contrarily, intense GnIH-ir cells on both the capsular layers peaked during testicular regression. Differential structural alterations of the testicular capsule provide mechanical support and help maintain internal homeostasis in tune with changing seasons. The seasonal expressions and alterations of reproduction-related receptors, hormones, and neuropeptides provide evidence for the potential regulatory roles of the capsule in the peripheral modulation of intratesticular functions.

Immunohistochemical Changes in the Testicular Excurrent Duct System of Healthy, Male Japanese Quail (Coturnix coturnix japonica) Observed at 4, 6-7, 12, and 52 Weeks of Age

The immunolocalization of the cytoskeletal and the extracellular matrix proteins was investigated in the testicular excurrent duct system of healthy Japanese quail at 4, 6−7, 12 and 52 weeks of age. TdT dUTP Nick End Labeling (TUNEL) assay was used to assess apoptotic cell formation. The epithelia of the testicular excurrent duct system in birds of all age groups displayed various immunolabeling intensities and localization of cytokeratin 5 and beta-tubulin, while α-SMA was observed in epithelia only of 4-week-old birds. In all age groups, vimentin immunostaining was observed in the rete testes and efferent ductular epithelia, but not in the epididymal duct unit. The periductal smooth muscle cells of the excurrent duct system displayed variably intense immunopositivity with cytokeratin 5, desmin, fibronectin, α-SMA, and beta-tubulin. Furthermore, beta-tubulin and vimentin immunolabeled endothelial cells and fibroblasts with various intensities, while fibronectin immunostained extracellular matrices surrounding these cells. TUNEL-positive apoptotic cells were observed in the rete testes and efferent ductular epithelia, with increased frequency (p < 0.001) in 52-week-old birds. The study serves as a baseline normal for this region in healthy birds at 4, 6−7, 12, and 52 weeks of age, for comparison in future similar immunohistochemical studies involving environmental toxins affecting this region.

A Role for Exchange of Extracellular Vesicles in Porcine Spermatogonial Co-Culture

Spermatogonial stem cells (SSCs) provide the basis for lifelong male fertility through self-renewal and differentiation. Prepubertal male cancer patients may be rendered infertile by gonadotoxic chemotherapy and, unlike sexually mature men, cannot store sperm. Alternatively, testicular biopsies taken prior to treatment may be used to restore fertility in adulthood. Testicular SSC populations are limited, and in vitro culture systems are required to increase numbers of SSCs for treatment, demanding culture systems for SSC propagation. Using the pig as a non-rodent model, we developed culture systems to expand spermatogonia from immature testis tissue, comparing different feeders (Sertoli cells, peritubular myoid cells (PMCs) and pig fetal fibroblasts (PFFs)). Spermatogonia co-cultured with Sertoli cells, PMCs and PFFs had comparable rates of proliferation and apoptosis. To elucidate the mechanism behind the beneficial nature of feeder layers, we investigated the role of extracellular vesicles in crosstalk between spermatogonia and feeder cells. Sertoli cell-released exosomes are incorporated by spermatogonia, and inhibition of exosomal release reduces spermatogonial proliferation. Together, these results show that PMCs, PFFs and Sertoli cells promote spermatogonial proliferation in co-culture, with exosomal exchange representing one possible mechanism. Further characterization of exosomal cargo may ultimately allow the development of feeder-free culture systems for clinical use.

Antibody selection for immunocytochemical characterization of the male reproductive system in Psittaciformes

The success of breeding programs is limited by the sparse knowledge about endocrine regulation and biochemical reactions in the psittacine male tract. The immunocytochemical analysis of parrots' testicular tissues provides an insight into their reproductive system but is often hampered by the lack of reliable antibodies. In the present study, we tested a large panel of antibodies raised against steroid receptors, steroidogenic enzymes, relaxin peptides including their receptors, and proliferation markers on paraffin sections of testicular tissue from eight psittacine genera representing three continents. All investigated species displayed the tested markers in somatic and germ cells of testis and epididymis, even though cell distribution was partly heterogenous and in species-specific patterns. The 17β-hydroxysteroid-dehydrogenase-2, 3β-hydroxysteroid-dehydrogenase, and smooth muscle actin allowed the cross-species differentiation between active and nonactive gonads. The remaining steroidogenic enzymes, steroid receptors, relaxin peptides, and Ki67 proved to be suitable to define reproductive activity depending on the parrot species. Adapting immunocytochemical methods to different psittacines was successful, though various cellular expression patterns do not allow the transfer of results among different parrot species. However, the availability of a reliable repertory of sexual markers is important to examine reproductive biology of psittacine birds.

Post-hatch changes in the immunoexpression of desmin, smooth muscle actin and vimentin in the testicular capsule and interstitial tissue of the Japanese quail (Coturnix coturnix japonica)

The post-hatch development of immunoreactivity to desmin, smooth muscle actin (SMA) and vimentin in the testicular capsule and interstitial tissue of day-old to adult quails was described in this study. The tunica albuginea of the testicular capsule was composed mainly of myoid cells. A zonal arrangement of desmin and SMA immunostaining was observed in myoid cells of the tunica albuginea in 1- to 24-day-old quails. Immunostaining for SMA and desmin was uniform in the tunica albuginea of adult birds. Vimentin immunostaining in the testicular capsule was demonstrated in mesothelial cells, endothelial cells and fibroblasts. The interstitial tissue contained mesenchymal cells, peritubular myoid cells, Leydig cells and fibroblasts. Desmin-immunopositive mesenchymal cells were present in the interstitial tissue of 1- to 17-day-old quails. Peritubular myoid cells expressed strong desmin immunostaining in all developmental stages, while the intensity of SMA immunostaining increased with testicular maturation. Vimentin was demonstrated in Leydig cells and fibroblasts, while the peritubular myoid cells displayed strong vimentin immunostaining only in adult birds. Strong vimentin immunostaining was demonstrated in the endothelial cells of capsular and interstitial blood vessels. The tunica media of these blood vessels displayed desmin and SMA immunostaining. The results of the study have established that variability exists in the distribution and intensity of desmin, SMA and vimentin immunostaining in the testicular capsule and interstitial tissue of the post-hatch Japanese quail.

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

Using immunohistochemistry (IHC), this study aimed to evaluate the regional distribution pattern of some biologically active proteins in the epididymis of Egyptian water buffalo and to determine the structural-functional relationships of the different epididymal structures. Wax-embedded sections from different regions of the epididymal duct from adult, clinically healthy, buffalo bulls were used. Primary antibodies against angiotensin converting enzyme (ACE), S-100, galactosyltransferase (GalTase), alpha smooth muscle actin (α-SMA), connexin 43 (Cx43) and vascular endothelial growth factor (VEGF) were used for immunohistochemical studies. The results showed that, in addition to the well-known principal and basal cells, the epididymal epithelium, similar to that of other species, possessed apical cells and intraepithelial leukocytes. IHC showed that, with the exception of VEGF which reacted negatively, all antibodies used displayed variable reactivity in the different epididymal structures. Apical cells expressed a strong reaction with ACE along the entire length of the duct. The principal cells in the caput epididymis exhibited a distinct reactivity with S-100 and GalTase. The peritubular muscular coat displayed a marked immunostaining for α-SMA and for Cx43. In conclusion these findings showed a regional-specific distribution pattern, distinct from that in bovine bulls. Some potential functional capacities, especially absorptive and secretory ones, are discussed in relation to the different epididymal regions.

Comparative expression of laminin and smooth muscle actin in the testis and epididymis of poultry and rabbit

The present investigation was conducted to demonstrate laminin and alpha smooth muscle actin (alphaSMA) in the testis and epididymis of adult chickens, Sudani ducks, pigeons, and rabbits. This study may represent the first indication for the presence of laminin in the male reproductive organs of birds and rabbits and might therefore serve as a milestone for further reports. In the testis of chicken, Sudani duck, pigeon, and rabbit, the laminin was localized in the basal lamina of the seminiferous tubules and of the peritubular myoid cells, in the testicular capsule and to a small extent in the vicinity of Leydig cells. The testicular vasculature also exhibited intense laminin immunostaining. Weak laminin staining was additionally seen in the cytoplasm of the duck Sertoli cells. In the epididymis, the basal lamina of the epididymal epithelium showed a distinctly positive reaction in all birds and rabbit. The basal lamina of the periductal myoid cells also showed a positive reaction. In the interductal tissue, laminin immunostaining was particularly observed in chicken, duck and pigeon. Laminin positive reaction was also seen in the epididymal vasculatures of all birds and rabbit. Interestingly, weak to moderate laminin staining was observed in the apical surface of the ciliated cells of the proximal and distal efferent ductules in chicken, duck and pigeon. alphaSMA positive reaction was seen in the testicular capsule and in the peritubular myoid cells of all birds and rabbit. In the testicular capsule, alphaSMA staining was either observed in the inner portion (chicken) or throughout the tunica albuginea (Sudani duck and pigeon), or in the outer aspect (rabbit). Distinct alphaSMA reaction was additionally observed in the testicular vasculature. In the epididymis of all birds and rabbit, the alphaSMA was particularly seen in the periductal and interductal myoid cells as well as in the epididymal vasculatures. No alphaSMA specific staining was however detected in the epididymal epithelium, fibrous lamina propria, and luminal spermatozoa of all birds and rabbits. In conclusion, the distribution of laminin and alphaSMA in the testis and epididymis might point out to their roles in the male reproduction.

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.

Morphological and immunohistochemical study of testicular capsule and peritubular tissue of emu (Dromaius novaehollandiae) and ostrich (Struthio camelus)

The testicular capsule and peritubular boundary tissue of the emu and ostrich, as typical representatives of ratite birds, were studied in sexually mature and active birds. The testicular capsule was much thicker (578.1+/-73.4 microm for the free surface of the ostrich testis, and 176.2+/-57.5 microm for the emu) than those of members of the Galloanserae. The cellular composition of both testicular capsule and peritubular tissue was similar generally to that of members of the previously studied Galloanserae and of mammals. The tunica albuginea of the testicular capsule mainly comprised smooth-muscle-like or myoid cells mostly running in one direction and occurring in one main mass. Unlike the Galloanserae, the tunica albuginea contained more collagen fibres than smooth muscle cells, especially in the ostrich. Peritubular tissue was similarly composed of smooth-muscle-like cells distributed in several layers. Actin microfilaments and desmin and vimentin intermediate filaments were variably immunoexpressed in these two tissue types in both birds, with a clear dichotomy in the peritubular tissue. Thus, taken together with studies of some members of the Galloanserae, avian testes clearly contain a morphological mechanism that is represented partly by the smooth muscle cells of the testicular capsule and peritubular tissue for transporting the testicular fluid, which is usually copious in birds, and its cellular content from the testis into the excurrent duct system; this mechanism is similar to that found in mammals.

The testicular capsule and peritubular tissue of birds: morphometry, histology, ultrastructure and immunohistochemistry

The testicular capsule was studied histologically, morphometrically, ultrastructurally and immunohistochemically in the Japanese quail, domestic fowl, turkey and duck (all members of the Galloanserae). The testicular capsule was, relative to mammals, thin, being 81.5 +/- 13.7 microm in the quail, 91.7 +/- 6.2 microm in the domestic fowl, 104.5 +/- 29.8 microm in the turkey and 91.8 +/- 18.9 microm in the duck. The orchido-epididymal border (hilus) of the capsule was much thicker than elsewhere in all birds (from 233.7 +/- 50.7 microm in the duck to 550.0 +/- 147.3 microm thick in the turkey). The testicular capsule, other than the tunica serosa and tunica vasculosa, comprised, in the main, smooth muscle-like or myoid cells running mainly in one direction, and disposed in one main mass. Peritubular tissue was similarly composed of smooth muscle-like cells disposed in several layers. Actin and desmin intermediate filaments were immunolocalized in the inner cellular layers of the capsule in the quail, domestic fowl and duck, but uniformly in the turkey. Vimentin intermediate filament immunoreaction in the capsule was moderately and uniformly positive in the testicular capsule of only the quail. Actin and desmin, but not vimentin (except very faintly in the turkey) or cytokeratin, were immunolocalized in the peritubular tissue of all birds. The results therefore establish, or complement, some previous observations that these birds have contractile cells in their testicular capsule and peritubular tissue, whose function probably includes the transport of testicular fluid into the excurrent duct system.

Postnatal Developmental Changes in Immunohistochemical Localization of .ALPHA.-Smooth Muscle Actin (SMA) and Vimentin in Bovine Testes

The present study demonstrates the postnatal developmental changes in immunohistochemical localization of alpha-smooth muscle actin (SMA) and vimentin in the bovine testis. In the peritubular myoid cells of seminiferous tubules and the sub-epithelial and stromal cells of straight tubules and the rete testis, alpha-SMA starts appearing at around 4 months of age. Peritubular alpha-SMA attains the continuous mature pattern at around 5 months of age whereas sub-epithelial and stromal alpha-SMA increases with advancing age. Vimentin is localized in the perinuclear zone of Sertoli cells, peritubular and vascular wall cells, a few interstitial cells, and in the basal part of the epithelia of straight and rete tubules. Developmental changes are only evident in the Sertoli cell vimentin, which is basal and weak at birth and increases moderately until 4 months of age. From around 5 to 8 months of age when the Sertoli cells are under morphological transformation, vimentin intensity is considerably increased and the characteristic vimentin extensions connect the Sertoli nuclei to the basal membrane. These extensions get shorter at around 9 month of age as the Sertoli nuclei are positioned basally. The mature Sertoli cell perinuclear vimentin is strong and stable without infranuclear extension. In conclusion, the age of appearance of alpha-SMA coincides with the onset of postnatal division of spermatogonia, and vimentin may play a key role in stabilizing Sertoli cell nuclei during their transformation in bovine.