The cytoskeletal proteins in the contractile tissues of the testis and its excurrent ducts of the passerine bird, Masked Weaver (Ploceus velatus)

The cellular composition of the testicular capsule, seminiferous peritubular tissue, the epithelia as well as periductal muscle cell layers of the excurrent ducts was studied, in sexually mature and active Masked Weaver (Ploceus velatus) birds of the passerine family, Ploceidae. Ultrastructure of the contractile cells in the testicular capsule, peritubular and periductal tissues showed that these cells were smooth muscles of typical morphological characteristics. Variability in the immunohistochemical co-expression of microfilaments and intermediate filaments in the different tissues was evident. Actin and desmin proteins were co-expressed immunohistochemically in the testicular capsule and seminiferous peritubular smooth muscle layer. Actin was singly and very weakly expressed in the rete testis epithelium while cytokeratins and desmin were co-expressed in the epithelium of the excurrent ducts. The periductal muscle layer of all ducts of the epididymis, the ductus deferens as well as the seminal glomus, strongly co-expressed actin and desmin. Vimentin was absent in all cells and tissue types studied. There is clear evidence that the tissues of the male gonad and its excurrent ducts in the Masked Weaver, as has been reported for members of the Galloanserae and Ratitae, contain well-formed contractile tissues whose function would include the transportation of luminal through-flow from the testis into, and through, its excurrent ducts. The microtubule helix in the head and of the mid-piece, of elongating spermatids, as well as of the mature spermatozoa in the various excurrent ducts, including some spermatozoa in the seminal glomus, also co-expressed these three proteins.     

Changes in the Peritubular Tissue of Rat Testis after Cadmium Treatment

The present study demonstrates histological and immunohistochemical changes in the peritubular testicular tissue of rat testis after application of cadmium chloride. After 5-day cadmium exposure, advanced deterioration of the boundary testicular tissue, mainly oedema, disarrangement of collagen fibres and peritubular cells, dilatation and thrombosis of blood vessels were observed. Changes in the boundary tissue were accompanied with desquamation of the germinal epithelium. Immunohistochemically, positive reaction for α-smooth muscle actin and desmin in tunica media of large testicular blood vessels basically was not affected. No reaction for vimentin was seen in endothelial cells of blood capillaries, whereas positive reaction presented only these cells in large blood vessels. The myofibroblasts positively reacting for desmin and α-smooth muscle actin form a single incomplete layer in the lamina propria of seminiferous tubules. Vimentin reactivity in the myofibroblasts and in the supporting Sertoli cells as well as Leydig cells in damaged testicular tissue was not observed. An increase in fibroblasts and free inflammatory cells positive for vimentin in the peritubular space on the peripheric area of the testis was observed.     

Intermediate filaments and epithelial differentiation of male rat embryonic gonad

The presence and distribution of desmin, vimentin, cytokeratin, and laminin in the gonads of developing male rat embryos (11-17 days) were studied by immunocytochemistry. The findings were correlated with morphological changes of the cells and with the formation of basement membranes, as determined by electron microscopy. The surface epithelial and subepithelial cells of the meesonephros in the prospective gonadal region contained desmin. At the onset of gonadal development, vimentin appeared in the somatic cells of the thickening surface epithelium, which formed the gonadal ridge. Desmin disappeared and cytokeratins appeared in the Sertoli precursor cells at the inception of their epithelial differentiation. Simultaneously, the prospective Sertoli cells became polarized during their assembly into epithelial cell aggregates; the aggregates then fused and formed elongated testicular cords. The epithelial cell differentiation was accompanied by a deposition of basement membrane material around the cords and by an increase of desmin in the cells immediately around the cords. With further differentiation of the testicular cords, some cytokeratins from the Sertoli cells, but not from the cells of the rete cords, disappeared. On the other hand, other cytokeratin polypeptides and vimentin remained in the fetal Sertoli cells. The surface cell layer slowly differentiated towards a proper epithelium after the basic formation of the testicular cords and interstitium. Desmin and vimentin persisted in the interstitial cells throughout the entire study period. The early differentiation of the gonad is apparently under a general sex-independent initiation program. The developmental changes in intermediate filaments offer an opportunity for the further analysis of their general role in early organogenesis. In light of the genetic theory of testicular differentiation, the functions of the regulatory factor(s) include specific organization of cord cells, histological organization into looping cords rather than separated follicles, and male development of the interstitium, surface epithelium and tunica albuginea.     

Immunohistochemistry of the cytoskeleton in the excurrent ducts of the testis in birds of the Galloanserae monophyly

The presence, location and degree of immunoexpression of various microfilament (MF) and intermediate filament (IF) systems (actin, cytokeratins, desmin, vimentin) were studied in the excurrent ducts of the testis in sexually mature and active galliform (Japanese quail, domestic fowl, turkey) and anseriform (duck) birds. These proteins were variably expressed between the epithelia and periductal tissue (periductal smooth muscle cell layer and interductal connective tissue) types and between species. Variable heterogeneous co-expression of filament systems was also found in the various duct epithelia and periductal tissue types: co-expression of filament systems was the rule rather than the exception. In the duck, neither vimentin nor cytokeratin was present in any of the tissues, whereas actin and desmin (absent in the rete testis) were co-expressed in the efferent ducts and epididymal duct unit (comprising the ductus conjugens, ductus epididymidis and ductus deferens). Actin, desmin and vimentin were generally co-expressed in the rete testis, efferent ducts and epididymal duct unit of the quail, domestic fowl and turkey, with vimentin being more strongly immunoreactive than actin and desmin in the epididymal duct unit, but more weakly immunoexpressed in the efferent ducts. Cytokeratin was present and co-expressed with actin, desmin and vimentin in the rete testis, efferent ducts and epididymal duct unit of the domestic fowl and turkey, but not in the quail and duck. The periductal smooth muscle cell layer and interductal tissue co-expressed actin, desmin and vimentin variably in all birds. Luminal spermatozoa of both the turkey and duck were immunonegative for all protein systems, whereas those of the quail and domestic fowl co-expressed actin, desmin and vimentin moderately or strongly. The tissues of the reproductive tract of male birds thus contain cytoskeletal protein systems that are variably but mostly co-expressed and whose contractile ability appears necessary and sufficient for transportation through the various excurrent ducts of the voluminous testicular fluid and its high sperm content, characteristic features of male avian reproduction.     

Seasonal spermatogenic cycle and morphology of germ cells in the viviparous lizard Mabuya brachypoda (Squamata,Scincidae)

We describe seasonal variations of the histology of the seminiferous tubules and efferent ducts of the tropical, viviparous skink, Mabuya brachypoda, throughout the year. The specimens were collected monthly, in Nacajuca, Tabasco state, Mexico. The results revealed strong annual variations in testicular volume, stages of the germ cells, and diameter and height of the epithelia of seminiferous tubules and efferent ducts. Recrudescence was detected from November to December, when initial mitotic activity of spermatogonia in the seminiferous tubules were observed, coinciding with the decrease of temperature, photoperiod and rainy season. From January to February, early spermatogenesis continued and early primary and secondary spermatocytes were developing within the seminiferous epithelium. From March through April, numerous spermatids in metamorphosis were observed. Spermiogenesis was completed from May through July, which coincided with an increase in temperature, photoperiod, and rainfall. Regression occurred from August through September when testicular volume and spermatogenic activity decreased. During this time, the seminiferous epithelium decreased in thickness, and germ cell recruitment ceased, only Sertoli cells and spermatogonia were present in the epithelium. Throughout testicular regression spermatocytes and spermatids disappeared and the presence of cellular debris, and scattered spermatozoa were observed in the lumen. The regressed testes presented the total suspension of spermatogenesis. During October, the seminiferous tubules contained only spermatogonia and Sertoli cells, and the size of the lumen was reduced, giving the appearance that it was occluded. In concert with testis development, the efferent ducts were packed with spermatozoa from May through August. The epididymis was devoid of spermatozoa by September. M. brachypoda exhibited a prenuptial pattern, in which spermatogenesis preceded the mating season. The seasonal cycle variations of spermatogenesis in M. brachypoda are the result of a single extended spermiation event, which is characteristic of reptilian species. J. Morphol. © 2012 Wiley Periodicals, Inc.     

Sertoli and Leydig cells of the human testis express neurofilament triplet proteins

 Using RT-PCR, western blot and enzyme and fluorescence immunocytochemical techniques, the three isoforms of neurofilament proteins (NFPs), namely NF-L (NFP-68 kDa), NF-M (NFP-160 kDa) and NF-H (NFP-200 kDa) were found in Sertoli and Leydig cells of human testes. RT-PCR showed specific for the three NFP fragments in testicular tissue, in isolated seminiferous tubules and in isolated Leydig cells. In protein preparations from the same testicular components, western blot analysis detected bands with molecular weights characteristic for NF-H, NF-M and NF-L. Application of immunofluorescence and immunoenzyme methods on cryostat and paraffin sections resulted in differences in the staining pattern in Sertoli cells and Leydig cells. In these cells, the NFPs showed predominantly a perinuclear location from which bundles emerge that were directed towards the basal, apical and lateral extensions of the Sertoli cells as well as the periphery of Leydig cells. NF-H coexists with vimentin-type filaments as seen by dual staining and staining of conseccutive serial sections of material embedded in paraffin. In Sertoli cells, vimentin and NF-H showed distinct dynamic changes depending on the stage of spermatogenesis and some structural variations of seminiferous tubules. Although in some tubules both vimentin and NF-H immunoreactivity was present at high levels, in the Sertoli cells from most individuals an inverse relationship in the staining intensity of vimentin and NF-H was observed. The strongest NF-H immunoreactivity was detected in Sertoli cells associated with stage 3 spermatids, whereas vimentin immunoreactivity was most abundant in association with stage 5 spermatids. The leydig cells did not show functional changes of the NFP immunoreactivity. The results obtained provide new evidence for the heterogeneous phenotype of human Sertoli cells and raise the question of their exact nature and origin. Accepted: 17 November 1998     

Immunocytochemical and quantitative study of the tunica albuginea testis in young and ageing men

 A light and electron microscope immunohistochemical study of the tunica albuginea from both young and elderly men was carried out to determine the distribution of the cells that contain actin, vimentin and/or desmin, and to evaluate the possible variations with ageing by means of quantitative studies. Testicular volume and testicular parenchyma volume decreased significantly with age whereas the tunica albuginea volume remained unchanged. These results agree with the scanty quantitative changes observed in the testicular connective tissue with age, and the notion that age-related changes in testicular volume are principally restricted to the seminiferous tubules. Three connective tissue layers could be distinguished in the tunica albuginea in both young and elderly men. The middle and inner layers increased in width with age while the width of the outer layer decreased. The average width of the tunica albuginea increased significantly with ageing. The tunica albuginea of young men and elderly men presented two types of fusiform cells: (1) fibroblast-like cells, which immunoreacted to actin and vimentin, but not to desmin; and (2) myoid cells, which immunoreacted to actin, vimentin and desmin. In both young men and elderly men, the total number of desmin-positive cells (myoid cells) was significantly lower than that of fibroblasts. However, the total number of desmin-positive cells was significantly increased in ageing men. In young testes, desmin-positive cells were more abundant in the outer layer of the tunica albuginea, whereas in elderly men these cells predominated in the middle layer. The increased desmin immunoexpression in the tunica albuginea of ageing men contrasts with the decrease in desmin immunoreaction in other myoid cells of the testis, the peritubular myoid cells, but only in seminiferous tubules that showed severe germ cell depletion. This suggests that changes in intermediate filament immunoexpression in peritubular cells are focalised, and thus, under local control, whereas changes in the tunica albuginea cells are generalised and possibly related to factors also affecting the connective tissue in other organs Accepted: 15 January 1997     

Distribution of gelsolin in human testis

Gelsolin, an actin-binding and severing protein present in many mammalian cells, was characterized in human testis. Although abundant in testicular extracts, gelsolin was not detected in purified spermatogenic cells by immunoblot analysis. Immunofluorescence studies of testis sections showed that gelsolin has two main localizations: peritubular cells and the seminiferous epithelium. In peritubular cells, gelsolin was present together with α-SM actin, in agreement with the myoid cell characteristics of these cells. In a large proportion of the tubules, gelsolin was found mainly, together with actin, in the apical part of the seminiferous epithelium. This localization of gelsolin also was observed in seminiferous tubules with a partial or complete absence of germinal cells, which evokes a presence of gelsolin at the apex of Sertoli cells. However, in normal testis, a complex pattern of gelsolin labeling was also present, mostly in the apical third of the epithelium, around cells or groups of cells, mainly spermatids, and, less frequently, in various other localizations from the apical to the basal part of the seminiferous epithelium. Taken together, these observations suggest that gelsolin may play different functions in the seminiferous epithelium: (1) regulation of the dynamic alterations of the actin cytoskeleton in the apical cytoplasm of Sertoli cells, and (2) modification of actin filaments assemblies in specific structures at germ cell-Sertoli cell contacts. Thereby, the actin-modulating properties of gelsolin are probably involved in reorganization of the seminiferous epithelium related to germ cell differentiation. Mol. Reprod. Dev. 48:63–70, 1997. © 1997 Wiley-Liss, Inc.     

A cytological and cytoskeletal comparison of Sertoli cells without germ cell and those with germ cells using the W/WV mutant mouse.

The distribution of F-actin and intermediate filaments in the W/WV mouse was investigated by light and transmission electron microscopy, and fluorescence methods. No spermatogenic cells were detected in the seminiferous epithelium of the W/WV mouse. Its seminiferous tubule was one-half the diameter of that in the normal (+/+) mouse. The Sertoli cell which was an only component of the W/WV mouse seminiferous epithelium was decreased in height, but still retained the polarity as evidenced by light microscopy. The Sertoli cell organelles were similar in appearance when normal and mutant mice were compared. F-actin was recognized at ectoplasmic specialization (ES) of the W/WV mouse Sertoli cell and appeared similar to the normal mouse. However, the junction with ES was more extensive compared with that of the normal mouse Vimentin in the W/WV mouse Sertoli cell was distributed around the nucleus and extended towards the tubular lumen similar to the normal mouse. Its extension within the Sertoli cell trunk, however, was restricted to a lesser degree as compared with that in the normal. Thus, the subcellular Sertoli cell and the distribution of F-actin and intermediate filaments (vimentin) in the W/WV mouse Sertoli cell seemed not to be strikingly affected by lack of spermatogenic cells, suggesting minimal influence of germ cells on Sertoli cell cytology and cytoskeleton.     

Distinction between vascular smooth muscle cells and myoepithelial cells in primary monolayer cultures of human breast tissue

Summary We report on the discrimination of vascular smooth muscle cells and myoepithelial cells in primary cultures of human breast tissue. Breast tissue was disaggregated enzymatically and the resulting organoids seeded in monolayer culture on collagen-coated plastic in serum-free medium CDM3a. Two main types of organoids were present after enzymatic digestion. One resembled small blood vessels and the other interlobular ducts or acini of the breast gland epithelium. Within 3 to 8 d after plating the organoids migrated into typical monolayer islets. These monolayer islets were evaluated using phase contrast microscopy and further tagged with monoclonal antibodies for immunocytochemical demonstration of Factor VIII-related antigen, muscle iso-forms of actin, type IV collagen, vimentin, desmin, and keratins. It is concluded that vascular smooth muscle cells resembled myoepithelial cells by expressing vimentin filaments, depositing type IV collagen, and showing immunoreactivity to muscle iso-forms of actin. However, whereas vascular smooth muscle cells were associated with endothelial cells and sometimes expressed desmin, myoepithelial cells appeared together with luminal epithelial cells and expressed cytokeratins. This work was supported by the Danish Medical Research Council, the Danish Cancer Society, the NOVO Foundation, and the Thaysen Foundation.     

Expression of fetal-type intermediate filaments by 17-day-old rat Sertoli cells cultured on reconstituted basement membrane

Summary The expression of cytokeratin- and vimentin-type intermediate filaments was studied by means of immunohistochemistry in Sertoli cells cultured on two types of reconstituted basement membrane in two-compartment culture chambers. In situ, the Sertoli cells of 17-day-old rats contained only vimentin intermediate filaments. During culture, a gradual reorganization of intermediate filaments accompanied by an increased cytokeratin immunoreactivity was observed. After 6 days, Sertoli cells contained both cytokeratin and vimentin, and the same cytokeratin type as in fetal and newborn testis was revealed by electrophoresis and immunoblotting. The present study shows that the isolation and culture of Sertoli cells causes, even in an improved culture system qualitative changes in the expression of intermediate filament proteins.     

Immunohistochemical distribution of simple-epithelial-type keratins and other intermediate filament proteins in the developing human pituitary gland

Summary An immunohistochemical study of the production of the intermediate filaments [vimentin, cytokeratin, and glial filament acidic protein (GFAP)] during development of the pituitary gland was made by use of fetal and adult human pituitary tissue. Among these intermediate filament proteins in the anterior and intermediate lobes of the pituitary, cytokeratin is the first to appear, followed by GFAP and vimentin. However, only cytokeratin is seen during the period of morphogenesis of the pituitary gland, with the type-II subfamily cytokeratin 8 being the earliest to appear. Among the simple-epithelial-type cytokeratins, cytokeratins 8 and 19 were observed within the pituitary primordium during morphogenesis. Cells immunoreactive for cytokeratins 8 and 19 showed a heterogeneous three-dimensional distribution pattern in Rathke's pouch. Both cytokeratins 8 and 19 tended to be strongly positive at sites in the pituitary primordium where cells had become more loosely arranged (i.e., areas far from the diencephalon) but were only weakly positive in areas in which the epithelial cells were densely packed (i.e., areas closely associated with the diencephalon). It is concluded that, during the period of morphogenesis, Rathke's pouch has the intermediate filaments characteristic of simple epithelium and shows different immunoreactivity for simple-epithelial-type cytokeratins from place to place according to the extent of cellular differentiation.     

Localization of follicle-stimulating hormone (FSH) immunoreactivity and hormone receptor mRNA in testicular tissue of infertile men

Testicular biopsies from 82 oligo-or azoospermic male patients were subjected to immunostaining using anti-human FSH antibodies. Histological evaluation showed normal spermatogenesis (nspg) in 7 (FSH: 2.7±0.7), mixed atrophy (ma) in 63 (FSH:5.3±0.5), and bilateral or unilateral Sertoli Cell Only syndrome (SCO) in 12 (FSH:21.7±3.5) patients. For the relationship between FSH values and testicular histology, see Bergmann et al. (1994). FSH immunoreactivity was found exclusively in Sertoli cells and in some interstitial cells. Seminiferous epithelium showing normal or impaired spermatogenesis displayed only weak immunoreactivity compared to intense immunoreaction, i.e. large and numerous vesicles in Sertoli cells of SCO tubules in biopsies showing mixed atrophy or SCO. In addition, h-FSH receptor mRNA was demonstrated by in situ hydridization using biotinylated cDNA antisense oligonucleotides. Hybridization signals were found within the seminiferous epithelium exclusively in Sertoli cell cytoplasm associated with normal spermatogenesis and in epithelia showing different signs of impairment, including SCO. It is concluded that: (1) Sertoli cells are the only cells within the seminiferous epithelium expressing FSH receptors; (2) the accumulation of FSH immunoreactivity in Sertoli cells of SCO tubules appears to be a sign of impaired Sertoli cell function.     

Extracellular matrix components and testicular peritubular cells influence the rate and pattern of Sertoli cell migration in vitro

We report the patterns of migration of Sertoli cells plated on specific substrata, and the influences of testicular peritubular cells on these processes. Data presented indicate that while peritubular cells readily spread when explanted onto Type I collagen, Sertoli cells do not. A delay of 4 to 6 days occurs after Sertoli cells are plated before they begin to migrate randomly to form plaque-like monolayers on Type I collagen. These processes are dependent upon the synthesis and subsequent deposition of laminin and/or Type IV collagen by Sertoli cells, and are independent of fibronectin. A different behavior occurs when reconstituted mixtures of purified Sertoli cells and pertiubular cells are sparsely plated onto Type I collagen. Peritubular cells rapidly spread to form chains of cells between Sertoli cell aggregates. Sertoli cells then migrate on the surfaces of the peritubular cells, culminating in the formation of cable-like structures between aggregates. Evidence is presented that the Sertoli cell migration to form "cables" under these conditions is dependent upon fibronectin synthesized by peritubular cells, and is independent of the presence of laminin or Type IV collagen. We discuss the possible relevance of these data to the role which precursors of peritubular cells may play in determining the behavior of Sertoli cell precursors in vivo during tubulogenesis, or in the remodelling of the seminiferous tubule which occurs during different stages of the cycle of the seminiferous epithelium in spermatogenesis.     

Protein secretory patterns of rat Sertoli and peritubular cells are influenced by culture conditions

An approach combining two-dimensional gel electrophoresis and autoradiography was used to correlate patterns of secretory proteins in cultures of Sertoli and peritubular cells with those observed in the incubation medium from segments of seminiferous tubules. Sertoli cells in culture and in seminiferous tubules secreted three proteins designated S70 (Mr 72,000-70,000), S45 (Mr 45,000), and S35 (Mr 35,000). Cultured Sertoli and peritubular cells and incubated seminiferous tubules secreted two proteins designated SP1 (Mr 42,000) and SP2 (Mr 50,000). SP1 and S45 have similar Mr but differ from each other in isoelectric point (pI). Cultured peritubular cells secreted a protein designated P40 (Mr 40,000) that was also seen in intact seminiferous tubules but not in seminiferous tubules lacking the peritubular cell wall. However, a large number of high-Mr proteins were observed only in the medium of cultured peritubular cells but not in the incubation medium of intact seminiferous tubules. Culture conditions influence the morphology and patterns of protein secretion of cultured peritubular cells. Peritubular cells that display a flat-stellate shape transition when placed in culture medium free of serum (with or without hormones and growth factors), accumulate various proteins in the medium that are less apparent when these cells are maintained in medium supplemented with serum. Two secretory proteins stimulated by follicle-stimulating hormone (FSH) (designated SCm1 and SCm2) previously found in the medium of cultured Sertoli cells, were also observed in the incubation medium of seminiferous tubular segments stimulated by FSH. Results of this study show that, although cultured Sertoli and peritubular cells synthesize and secrete proteins also observed in segments of incubated seminiferous tubules anther group of proteins lacks seminiferous tubular correlates. Our observations should facilitate efforts to achieve a differentiated functional state of Sertoli and peritubular cells in culture as well as to select secretory proteins for assessing their possible biological role in testicular function.     

Transient coexpression of cytokeratin and vimentin in differentiating rat Sertoli cells

The expression of cytokeratin and vimentin type intermediate filaments were studied in fetal, postnatal, and adult rat testes. Immunocytochemical observations were correlated with the light and electron microscopic analysis of the developing organs. The Sertoli cell precursors in 15-day-old fetal testes contained both cytokeratin and vimentin. A gradual reorganization of both filaments, accompanied by a decrease of cytokeratin-positivity, was observed toward the end of the fetal period. The simultaneous presence of cytokeratin and vimentin in the same cells was shown by double immunofluorescence of newborn testes and the primary culture of dissociated testicular cells. In postnatal Sertoli cells, cytokeratin-positivity continued to decrease and disappeared by the age of 14 days. The increase in vimentin content and the appearance of axially oriented vimentin filaments coincided with the acquisition of the columnar shape of the Sertoli cells. The presence of cytokeratin and vimentin in fetal and newborn testes, and only vimentin in the adult testes was confirmed by immunoblotting. The present results suggest that major qualitative changes in the expression of intermediate filament proteins can take place during the embryonic development. The expression of cytokeratin in developing Sertoli cells, although only transient, supports the epithelial origin of these cells and can be applied as a marker for embryonic and early postnatal Sertoli cells.     

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 α smooth muscle actin (αSMA) 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. αSMA positive reaction was seen in the testicular capsule and in the peritubular myoid cells of all birds and rabbit. In the testicular capsule, αSMA 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 αSMA reaction was additionally observed in the testicular vasculature. In the epididymis of all birds and rabbit, the αSMA was particularly seen in the periductal and interductal myoid cells as well as in the epididymal vasculatures. No αSMA 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 αSMA in the testis and epididymis might point out to their roles in the male reproduction.     

Ultrastructure and histochemistry of the testicular efferent duct system and spermiogenesis in Opistognathus whitehurstii (Teleostei, Trachinoidei)

 Testis organization and spermatogenesis, with the emphasis on spermiogenesis, in Opistognathus whitehurstii are described by ultrastructural and histochemical methods. The germinal epithelium is extremely reduced and restricted to the periphery of the testis, while most of the organ is occupied by a highly developed system of testicular efferent ducts. A semicystic type of spermatogenesis is observed and in the germinal epithelium spermatogenesis occurs only until the spermatidal stage. Young spermatids are released into the lumen of the testicular lobules and mature to sperm within the efferent duct system. The epithelial cells of these ducts are involved in protein and glycogen secretion and in phagocytosis of degenerating germ cells and residual bodies cast off by developing spermatids. On the basis of these functions, the testicular efferent duct system cells are considered to be homologous to the Sertoli cells. A correlation between a highly developed testicular efferent duct system and semicystic spermatogenesis is examined and a possible functional meaning of this apparently unusual mode of sperm production is proposed. Accepted: 18 March 1997     

In situ demonstration of both TUNEL-labeled germ cell and Sertoli cell in the cimetidine-treated rats

Cimetidine has caused dysfunction in the male reproductive system. In the rat testis, intratubular alterations and loss of peritubular tissue due to peritubular myoid cell death by apoptosis have been recently shown. Thus, the aim of this study is to evaluate which cells of the seminiferous epithelium have been affected and/or died by apoptosis after the treatment with cimetidine. For this purpose, an experimental group containing five male albino Wistar rats received intraperitoneal injections of cimetidine (50 mg/kg body weight) during 52 days. The testes were fixed with 4% buffered formaldehyde and were embedded in paraffin. For detection of DNA breaks (apoptosis) in the cells of the seminiferous epithelium, the testicular sections were treated by the TUNEL method (Apop-Tag Plus Peroxidase Kit). In the tubules affected by cimetidine, altered peritubular tissue, including the presence of TUNEL labeling in the myoid peritubular cells, were usually found. In these tubules, the seminiferous epithelium exhibited low density of germ cells and TUNEL-positive labeling in the germ cells of the basal compartment. The concomitant staining in both germ cells of the basal compartment and late spermatids suggest a sensitivity of these cells in the damaged tubules. Besides germ cells, TUNEL-positive Sertoli cells were also found in the injured seminiferous tubules. Thus, a relationship between dying germ cells and Sertoli cell damage and/or death must be considered in tubules where peritubular tissue has been affected by toxicants.     

Morphological and immunohistochemical study of testicular capsule and peritubular tissue of emu (<Emphasis Type="Italic">Dromaius novaehollandiae)</Emphasis> and ostrich (<Emphasis Type="Italic">Struthio camelus</Emphasis>)

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 μm for the free surface of the ostrich testis, and 176.2±57.5 μm 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 authors are grateful for a University of Pretoria research grant, which aided this work. Dr Peter Ozegbe of the Department of Veterinary Anatomy, University of Ibadan is a recipient of the University of Pretoria Foreign Post-Doctoral Fellowship.