Morphological and histochemical characteristics of the lamina propria in scrotal and abdominal testes from postpubertal boars: correlation with the appearance of the seminiferous epithelium

This study was undertaken to investigate the morphological characteristics and lectin affinity of the testicular lamina propria in healthy boars and in unilateral and bilateral abdominal cryptorchid boars. The lamina propria of scrotal testes from healthy boars and unilateral cryptorchid boars was constituted by an innermost noncellular layer, the basal lamina, and by 2 layers of peritubular cells, each separated by a fibrous layer. The noncellular layers contained collagen fibres and glycoconjugates with abundant N‐acetylgalactosamine, galactose, fucose, N‐acetylglucosamine and neuraminic acid residues. The inner peritubular cell layer was composed of myoid cells, the outer layer of fibroblasts. In the abdominal testes of unilateral and bilateral cryptorchid boars, the lamina propria of nondegenerating and degenerating seminiferous tubules appeared thickened due to an increased content of collagen fibres and glycoconjugates. Glycoconjugates showed decreased amounts of fucose, neuraminic acid and galactose, and increased amounts of N‐acetylglucosamine residues. The basal lamina formed infoldings toward the seminiferous epithelium and contained small cells. Both inner and outer peritubular cells were fibroblasts of immature appearance. In degenerated seminiferous tubules of bilateral cryptorchid boars, the lamina propria was composed of a thickened and collagenised basal lamina, without peritubular cells and with a low content of glycoconjugates. In scrotal testes, therefore, the lamina propria was implicated in tubular contractility and in mediating the communication and the substrate diffusion between seminiferous tubules and interstitial tissue. Cryptorchidism induced morphological and histochemical alterations in the lamina propria of abdominal testes, which may be linked to evidence from other studies of lack of tubular contractility and defective cell–cell communication and substrate diffusion. The severity of these anomalies correlated with the severity of Sertoli cell alterations.     

Effect of vasectomy on the seminiferous tubule boundary zone in the Albino Swiss rat

The boundary zone of a seminiferous tubule consists of the basement membrane of the seminiferous epithelium, its myoid cells, and their basal laminae. This study examines the boundary zones of seminiferous tubules in healthy and degenerated testes following long-term, left-sided vasectomy in the rat and compares them to those of sham-operated controls and adult rats exposed in utero to the antiandrogen, flutamide. Degenerated tubular profiles showed similar changes, irrespective of whether the degeneration was ipsilateral or bilateral. In transverse tubular profiles, the basal laminae of the seminiferous epithelium and the myoid cells became more undulating, that of seminiferous epithelium showing complex folding. The collagen layer of the boundary zone, which lies between the basal laminae of the seminiferous epithelium and the myoid cells, thickened and its fibers became irregularly orientated. Rather than being flattened as in controls, the region of the myoid cell near the nucleus and the nucleus itself developed triangular profiles in the transversely sectioned tubules. Similar features were also seen in the degenerated tubules of rats exposed to flutamide. The changes in the boundary zone are not specific for vasectomy and probably reflect reduction in the cross-sectional area of tubular profiles and possibly in their length. We also noted occasional leukocytes infiltrating the boundary zone; they may have increased in number in those tubules that showed degeneration following vasectomy.     

Testicular involution after optic enucleation: Ultrastructure and alkaline phosphatase cytochemistry of the peritubular tissue

Two months after blinding hamsters, the seminiferous epithelium had undergone pronounced involution. Spermatogonia were the only germ cells consistently present in the seminiferous tubules, although some tubules also contained primary spermatocytes. The peritubular tissue in the blinded hamster had undergone marked distortion. Irregular projections extended from the myoid cells and protruded toward the seminiferous epithelium. All layers of the peritubular tissue developed irregular contours and underwent thickening. The myoid cell nuclei were highly infolded, giving the nucleus a lobulated appearance. Golgi stacks often occupied recesses in the cytoplasm created by nuclear folding. Numerous vesicles were located at the poles of the Golgi stacks and were scattered between the Golgi stacks and the plasmalemma. Vesicles were also observed fusing with the plasmalemma. Alkaline phosphatase was localized cytochemically in the Golgi apparatus and the myoid cell vesicles. The appearance of the myoid cells in the involuting testes was similar to that of contracting smooth muscle; therefore, we postulate that the cytological alterations observed in the myoid cells may be a result of myoid cell contractions. Myoid cell vesicles have previously been thought to selectively take up substances at the interstitial surface of the myoid cell, transport the material across the cytoplasm and release their contents at the surface adjacent to the seminiferous epithelium. The findings reported in the present investigation indicate that some of these vesicles are involved in exocytosis of substances synthesized in the myoid cell. It appears that myoid cell exocytosis may be involved in formation of the alkaline phosphataserich basal laminae of the peritubular tissue.     

Proliferation and apoptosis of spermatogonia in postpuberal boar (Sus domesticus) testes with spontaneous unilateral and bilateral abdominal cryptorchidism

Cryptorchidism is a frequent male sexual disorder in mammals, which affects the histology of the tunica propria, interstitial tissue, blood vessels, seminiferous epithelium and testis functioning. In this paper, proliferation and apoptosis were examined in the seminiferous epithelium of both testes from unaffected boars and from boars suffering unilateral and bilateral cryptorchidism. In germ cells, proliferation was studied using the immunohistochemical PCNA technique, and apoptosis was analysed by in situ TUNEL labelling. An index was obtained for the proliferation and apoptosis observed in seminiferous tubules. In abdominal testes the epithelium contained few spermatogonia and Sertoli cells. In the testes of unaffected boars, numerous spermatogonia proliferated, whereas in cryptorchid testes such proliferation was lower and the proliferation/apoptosis ratio diminished. In the unaffected group, the TUNEL-positive germ cells were spermatogonia and spermatocytes in different phases of meiosis. In abdominal testes, the TUNEL-positive germ cells were spermatogonia alone. The apoptosis index of both abdominal and scrotal testes was similar. In conclusion, spontaneous cryptorchid testes showed a lower rate of spermatogonia proliferation in the seminiferous epithelium.     

Leydig cells within the aspermatogenic seminiferous tubules

Cells identical to Leydig cells were found within a peritubular boundary layer and even inside a basal lamina of seminiferous tubules in three male patients (two with inguinal cryptorchism and one with infertility). The seminiferous tubules of all patients showed a moderate to marked thickening of the boundary layer and a complete loss of spermatogenic cells. The "ectopic Leydig cells" were characterized by the presence of Reinke crystals or an extensively developed smooth endoplasmic reticulum. These cells were believed to have differentiated in situ from myoid cells within the boundary layer and also to have invaded from the interstitial tissue in the form of mature Leydig cells. The occurrence of ectopic Leydig cells appeared to parallel the extent of loss of the Sertoli cells and also that of the thickening of the boundary layer. The functional significance of the ectopic occurrence might be implicated in the impaired spermatogenesis.     

Multilayered structure of the basal lamina of the tubuli recti in normal mice

Previous studies have demonstrated that the blood-testis barrier (BTB) at the tubuli recti (TR) and the rete testis (RT) is less complete than at the seminiferous tubules (ST). However, there has been no report focusing on the basal lamina, which is an important component of the BTB at both TR and RT. In the present study, we performed electron microscopic observation of the basal lamina at the TR and RT, in comparison with that of those of the ST in normal mice. The results showed that the basal lamina of modified Sertoli cells at the TR segment exhibited a wavy and multilayered structure, but the Sertoli cells of ST and the epithelium of RT had an almost flat and singlelayered basal lamina. It was also noted that wide gaps existed between the modified Sertoli cells, the basal lamina of the epithelial layer, and the myoid cell layer at the middle TR segment. This characteristic structure of the basal lamina of the TR epithelial layer may be one of the factors for its incomplete BTB.     

Distinct changes in the laminin composition of basement membranes in human seminiferous tubules during development and degeneration.

We studied the distribution of laminin (Ln) chains and their integrin (Int) receptors in normal developing and adult and in atrophied human testes by using immunohistochemistry. Immunostaining for EHS Ln and type IV collagen was used to identify basement membranes (BMs). In the BM of seminiferous epithelium of fetal testis, a panel of monoclonal antibodies showed immunoreactivity for Ln alpha 1-, alpha 2-, beta 1-, beta 2- and gamma 1-chains, suggestive of the presence of Lns 1 to 3. In BM of adult seminiferous epithelium with active spermatogenesis, immunoreactivity for Ln beta 2- and gamma 1-chains was found but not for Ln alpha-chains, suggesting a complex of Ln chains not compatible with any known trimers. Instead, with polyclonal Ln antiserum and monoclonal antibody to type IV collagen, a distinct BM-like reactivity was seen. In atrophied testes, prominent immunoreactivities for Ln chains, compatible with Lns 1 to 3, were seen in the thickened BM of seminiferous tubules, hence suggestive of reappearance of fetal Lns. Among the subunits of Ln-binding Int receptors in fetal seminiferous tubules, a strong immunoreactivity for Int beta 1- and Int alpha 6-subunits was seen throughout the seminiferous epithelium, other Int subunits being found in interstitial cells. In the adult and atrophied testes, immunoreactivities for Int beta 1- and Int alpha 6-subunits were seen to be confined to the basal aspect of the seminiferous epithelium whereas immunoreactivities for Int alpha 1-, alpha 2-, alpha 3- and beta 4-subunits were seen in the myoid cells. The results show that both maturation and degenerative changes of human testes are accompanied by distinct changes in the Ln expression of BM of seminiferous epithelium, which appears to accompany epithelial differentiation of the Sertoli cells. Furthermore, they suggest the presence of a novel Ln trimer in BM of adult human seminiferous tubules.     

人与几种常用啮齿动物曲细精管周组织超微结构及碱性磷酸酶电镜细胞化学的定位

本文对人、兔、豚鼠、大鼠及小鼠的曲细精管周组织的超微结构和碱性磷酸酶(AIP)定位进行了观察。人的曲细精管周组织内一般有3层细胞,有细长分支突起,最内层呈肌样细胞特征,向外层的细胞则与成纤维细胞相似。相邻肌样细胞之间多见较宽的细胞间隙。AIP 位于基板、最内侧胶原原纤维区、肌样细胞胞质和向内侧质膜。4种啮齿动物曲细精管周组织微细结构基本相似,但也有某些区别。兔与豚鼠的单层肌样细胞的相邻末端可重叠排列呈2层,而大鼠和小鼠的肌样细胞则呈单层包绕。兔的基板为1～2层,其它3种动物只有1层。4种动物的相邻肌样细胞之间皆有紧密连接与宽度为100～200(?) 的开放间隙,以及更宽的细胞间隙。这4种动物的基板、内非细胞层、肌样细胞胞质及其向内侧质膜和淋巴窦内皮细胞皆有 AIP 分布,除兔以外,豚鼠、大鼠和小鼠的肌样细胞外侧质膜和外非细胞层也有 AIP 分布。本文讨论了曲细精管周组织及 AIP 酶鞘的生理意义。     

Degenerated tubules in the guinea pig testis after long-term vasectomy or sham operation

The testes of eight unilaterally vasectomized and six sham-operated Dunkin Hartley guinea pigs were examined 3 years after operation by wax and resin histology and transmission electron microscopy. Degenerated tubules are reported that were common on the side of vasectomy but also found in the contralateral testes and in the controls. A central accumulation of macrophages, rich in phagocytosed debris including spermatozoal fragments, was surrounded by attenuated Sertoli cells, a markedly thickened basement membrane and myoid cells. At some sites macrophages impinged directly on the basement membrane. They probably represented highly degenerated seminiferous tubules. The study suggests that the response to injury of seminiferous tubules may show species variations. Macrophages did not feature in the degenerated seminiferous tubules we reported following vasectomy in the rat. However, the rat showed striking changes in the morphology of the basal laminae and myoid cells which did not occur in the guinea pig. Pathological changes have been reported in the human testis following vasectomy but their etiology is unclear. Studies in the guinea pig are enhancing understanding of the mechanisms and features of testicular damage.     

高原地区藏绵羊与小尾寒羊睾丸细胞外基质组织分布特征比较

目的探索细胞外基质相关蛋白在高原地区藏绵羊与小尾寒羊睾丸的分布及组织化学特征。方法应用组织化学方法、Image-Pro Plus(IPP)图像分析技术及电子显微镜,观察比较藏绵羊(4只)与小尾寒羊(5只)睾丸组织化学特点及层黏连蛋白(LN)、Ⅳ型胶原(ColⅣ)和硫酸乙酰肝素糖蛋白(HSPG)的分布特征。结果与小尾寒羊睾丸相比,藏绵羊生精小管基膜及间质组织内胶原纤维及网状纤维丰富;过碘酸-雪夫(PAS)及阿利新蓝-过碘酸-雪夫(AB-PAS)染色显示,藏绵羊睾丸间质血管及生精小管固有膜阳性反应更为丰富。免疫组织化学显示,ColⅣ在藏绵羊及小尾寒羊生精小管上皮均呈阳性表达,LN在藏绵羊Sertoli细胞及管周肌样细胞呈弱阳性表达,而在小尾寒羊Sertoli细胞、Leydig细胞及管周肌样细胞为中等阳性表达;HSPG在藏绵羊及小尾寒羊肌样细胞均呈强阳性表达,而在Sertoli细胞及Leydig细胞均为弱表达。免疫组织化学图像分析结果显示,藏绵羊睾丸组织中ColⅣ和LN的分布显著低于小尾寒羊睾丸组织(P0.01),HSPG检测结果则显著高于小尾寒羊睾丸组织(P0.01)。电子显微镜下观察,藏绵羊及小尾寒羊生精小管固有膜可见发育良好的生殖上皮基膜以及1层明显的Ⅰ型胶原纤维,藏绵羊固有膜胶原纤维层丰富且Leydig细胞内脂滴明显。结论高原环境下藏绵羊睾丸固有膜及间质结缔组织较为丰富,在一定程度上影响了生精上皮发育;藏绵羊睾丸间质血管壁及生精小管固有膜AB-PAS阳性反应增强与Leydig细胞分泌功能相关,小尾寒羊睾丸组织LN表达显著增加及HSPG显著降低与生精上皮发育程度关系密切。     

Lamina propria of sex cords in human fetal testis: an immunohistological and stereological study

Testicular peritubular cells are located in the lamina propria of seminiferous tubules. These cells, significantly contributing to the basal membrane of seminiferous epithelium, have been studied in a number of species. However, there is a lack of data on the development of the lamina propria in the human testis. The aim of our survey was to investigate the characteristics of the lamina propria and, in particular, peritubular cells in the fetal human testes by immunohistological and stereological methods. Therefore, testes (14–39 weeks of gestation, n=45) were dissected and fixed in a 4% buffered paraformaldehyde solution. Several pieces of each testis were embedded in paraffin and processed for immunohistochemical and stereological analysis. All investigated testes have shown sex cords in the process of development and differentiation. Morphologically, peritubular cells in the lamina propria can be divided into two types: fibroblast-like (FL) and myoid-like (ML) type (cells which much resemble mature myoid cells). By immunohistochemistry, both FL and ML cells are found to be strongly positive for the intermediate filament desmin, but negative for -smooth actin. While FL cells intensively express Ki-67 demonstrating proliferative activity, ML cells are found to be negative. The basement membrane of sex cords as well as the blood vessels of the interstitium show strong positivity to collagen IV and laminin. Concerning the correlation between the appearance of the investigated antigens with the gestational age, all antigens have been expressed (in the manner described above) already in the 14th week of gestation. The stereological analysis of the number (Nv) and volume (Vv) of peritubular cells indicates a pulsatile development of these cells in the lamina propria of the human fetal testis. While the stereological variables determined for FL cells show a gradual decrease, the same variables determined for ML cells demonstrate a successive increase. It appears that the lamina propria of the fetal human testes shares many of the properties previously discovered in rodents.     

Changes in the arrangement of actin filaments in myoid cells and sertoli cells of rat testes during postnatal development and after experimental cryptorchidism

Background: Abundant actin filaments are present in myoid cells and Sertoli cells in the testis. In the adult rat, the filaments form a lattice arrangement within the myoid cell, and show a hexagonal pattern in the basal junctional regions of Sertoli cells. Methods: Isolated seminiferous tubules and frozen sections were prepared from juvenile to adult Wistar rat testes, stained with FITC-conjugated phalloidin, and observed by confocal microscopy. Unilateral cryptorchidism was induced in adult rats, and seven days later, their testes were also examined. Results: In the myoid cell, parallel actin filaments running circularly around the seminiferous tubules were observed at 15 and 20 days of age. Then, at 30 days, actin filaments arranged longitudinally along the tubular long axis appeared in addition to the circular bundles. A lattice arrangement of actin-filament bundles in myoid cells became obvious at 40 days, when elongated spermatids are found in the tubule. Actin filaments in the basal junctional regions of Sertoli cells did not acquire the hexagonal pattern seen in the adult testis until 30 days of age. In the cryptorchid testes, the arrangement of actin filaments in the both cells showed a remarkable change compared to the control testis; the filaments became thinner and disrupted. Conclusions: A lattice arrangement of the actin filaments in the myoid cell appear at around 30 days, before the completion of spermatogenesis. A hexagonal pattern of the filaments in the junctional regions of Sertoli cells has already developed at this age. Cryptorchidism affects the actin filaments of the both cells. © 1995 Wiley-Liss, Inc.     

The fine structure and development of the peritubular contractile cell component in the seminiferous tubules of the mouse

Testes of sexually mature, as well as newborn and young mice of varying ages were studied by electron microscopy. The seminiferous tubules in the mature mouse possess a single cell layer of extremely flattened cells which form a sheath-like structure around the epithelium of the tubule. These peritubular cells are characterized by cytoplasmic filaments and other features which are typical of smooth muscle cells. A basement lamina is associated with the interstitial or peripheral surface of the cell. Peripherally, there is an additional cellular layer consisting of connective tissue fibrocytes. In newborn animals, the cells surrounding the tubule epithelium consist of a homogeneous population of fibroblasts, 3–4 layers in thickness. With growth and development of the testes the number of cell layers is reduced and the cells become more attenuated. At 13 days, those cells which are closest to the epithelium show localized aggregates of fine filaments, as well as what appears to be the elaboration of a basement lamina. By 17 days, the cytoplasmic filaments are more numerous and the basement lamina is well defined: by 19 days, the cells closely resemble the peritubular muscle cells of the adult. The probable functional role of these cells is discussed with respect to both sperm transport and the production and maintenance of the surrounding connective tissue stroma.     

Case report of rat true hermaphroditism: colocalization of oocytes and granulosa and sertoli cells in the germinal cord

We describe a case of rat hermaphroditism with bilateral ovotestes. In a 7-week-old apparently male Sprague-Dawley rat, both testes were relatively small, and the right testis with a faint protrusion was somewhat round and small as compared with the left testis. Microscopically, the testes contained ovarian tissues within their tunica albugineas in conjunction with spermatogenesis in the seminiferous tubules. As bilateral changes, oocytes surrounded by granulosa-like cells were present in the seminiferous tubule-like germinal cord. Granulosa-like and Sertoli-like cells were layered together on the basal lamina, and theca interna-like cells were occasionally observed around the basal lamina. As unilateral changes, cystic dilatation of the germinal cords with eosinophilic fluid was seen in the lumen, and the theca interna-like cells appeared to be vacuolated. Immunohistochemically, the granulosa-like and Sertoli-like cells showed positive reactions for 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and vimentin, respectively. Theca interna-like cells reacted positively to both 3beta-HSD and cytochrome P-450 17alpha-hydroxylase. Ultrastructurally, the granulosa, Sertoli, and theca interna cells were also identified in the ovarian tissue. From these morphological characteristics, the male rat with bilateral ovotestes was diagnosed as true hermaphroditism.     

The peritubular myoid cells in the testes from men with varicocele: an ultrastructural, immunohistochemical and quantitative study

Ultrastructural and some immunophenotypic features of the peritubular myoid cells of testes from normal men and from men with varicocele were studied. The seminiferous tubules were classified into five types (a-e), related to the progressive degree of sclerosis measured as thickening of the lamina propria. In normal testes only type a and b tubules were found, whereas the testes from men with varicocele showed type b-e tubules. Myoid cells in tubule types a and b showed slender cytoplasmic projections with abundant, parallel arranged microfilament bundles and electron-dense bodies. In c tubules, the myoid cells showed the same ultrastructure. The myoid cells of tubules with advanced (type d) or complete (type e) sclerosis showed irregularly outlined nuclei, scant microfilament bundles and absence of electron-dense bodies. Immunostaining of myoid cells with anti-actin antibodies was intense in types a-c tubules and scant in types d and e. Immunostaining with anti-desmin antibodies was intense in tubules types a-d, but the immunoreactive cells in types c and d tubules were irregularly shaped and distributed and were scanty in tubule type e. Immunostaining with anti-vimentin antibodies was weak in types a-c tubules and intense in types d and e tubules. Quantitative studies revealed that, with the progression of sclerosis, the numbers of both actin- and desmin-immunoreactive cells per cross-sectioned tubule, and the surface area occupied by the immunostained portion of these cells, decreases while the number of vimentin-immunoreactive cells and their immunostained surface area increases.     

Arrangement of connective tissue components in the walls of seminiferous tubules of man and monkey

In primates the membrane separating the seminiferous epithelium from the interstitial space is composed of one to three (monkey) or two to six layers (man) of myoid cells associated with one to two layers of fibrocyte-like adventitial cells. All these cells are separated from each other by irregular spaces filled with various connective tissue intercellular components. Subjacent to the elements of the seminiferous epithelium is a continuous, often redundant, basement membrane. A similar basement membrane-like material forms a layer next to and over small areas of the plasma membrane of myoid cells. Collagen fibrils grouped in bundles of various sizes are seen in all connective tissue layers but are particularly abundant in the space between the seminiferous epithelium and the innermost layer of myoid cells. Elastic fibrils demonstrated by the Verhoeff iron hematoxylin technique are also present. Composed of a homogeneous material, the elastic fibrils are short, irregular, branching entities with a diameter comparable to or smaller than that of collagen fibrils. In addition, an abundance of microfibrils with a diameter of 12–15 nm is present in the various connective tissue layers. These microfibrils have a densely stained cortex and a lightly stained core. When seen close to the myoid cells, bundles of microfibrils appear to insert on well defined areas next to the plasma membrane. These areas commonly face the patches of electron-dense material observed on the inner aspect of the plasma membrane of the myoid cells and in which the actin filaments are inserted. Bundles of microfibrils often span the gap between myoid cells of the same layer as well as those of adjacent layers. Microfibrils are also closely related to the surface of elastic fibrils and are seen intertwining with collagen fibrils. Thus microfibrils appear to bridge and bind together adjacent myoid cells and anchor the surface of these cells to the bundles of elastic and collagen fibrils present in the intercellular spaces of the limiting membrane.     

Trypanosoma cruziand myoid cells from seminiferous tubules: interaction and relation with fibrous components of extracellular matrix in experimental Chagas' disease

The main transmission route of Trypanosoma cruzi is by triatomine bugs. However, T. cruzi is also transmitted through blood transfusion, organ transplantation, ingestion of contaminated food or fluids, or is congenital. Sexual transmission, although suggested since the discovery of Chagas' disease, has remained unproven. Sexual transmission would require T. cruzi to be located at the testes and ovaries. Here we investigated whether T. cruzi is present in the gonads of mice infected with 10⁴ T. cruzi trypomastigotes from the CL strain. Fourteen days after experimental infection, histopathological examination showed alterations in the extracellular matrix of the lamina propria of the seminiferous tubules. Furthermore, amastigotes were present in seminiferous tubules, within myoid cells, and in the adjacencies of the basal compartment. These results indicate that T. cruzi is able to reach seminiferous tubule lumen, thus suggesting that Chagas' disease could potentially be transmitted through sexual intercourse. Complementary studies are required to demonstrate that Chagas' disease can be transmitted by coitus.     

Vimentin expression during altered spermatogenesis in rats

The collapse of vimentin caused by some xenobiotics correlates with the loss of structural integrity of the seminiferous epithelium. In this study, we investigated the effect of busulphan (an anticancer drug with toxic effects on dividing germ cells) on vimentin filament distribution in rat seminiferous epithelium and compared it with changes found in testes of unilaterally cryptorchid rats. In the seminiferous epithelium, the vimentin labelling was observed only in the Sertoli cells, showing a stage-specific arrangement of the filaments. Both busulphan treatment and cryptorchism caused altered distribution of vimentin filaments in the Sertoli cells. In both models, the apical vimentin filaments collapsed towards the nuclei and were disorganized in the basal region of the Sertoli cells while the germ cells were diminished in the epithelium. After the busulphan effect subsided (4 weeks after administration), spermatogenesis began to restore and vimentin filaments began to organize in basal and perinuclear regions of Sertoli cells among the spermatogonia and spermatocytes. Vimentin labelling of the sloughed material in the lumen of cryptorchid testes (but not in busulphan treated animals) was observed. We conclude that the Sertoli cell vimentin filaments play an important role in the maintenance of spermatogenesis, their damage is associated with the seminiferous epithelium disintegration and their restoration with a recovery of spermatogenesis after the unfavourable conditions subside.     

Myoid elements in the mammalian nephron and their relationship to other specializations in the basal part of kidney tubule cells

The basal region of proximal convoluted tubule cells from mouse kidney was studied with the electron microscope. Particular attention was given to grazing sections, i.e., sections whose plane was approximately parallel to that of the basement lamina. The findings indicate that many of the “basal compartments” of the proximal convoluted cells are elongate parallel structures which contain aggregations of filaments resembling those of smooth muscle. These elongate structures, referred to as myoid bands, react positively with dyes which are selective for muscle tissue. Close membrane appositions are also seen in grazing sections, apparently related to the myoid bands, at least by virtue of location. In addition, the basal region of the proximal convoluted tubule cells possesses branching microvillous processes. Because of their arrangement, the basal extracellular space associated with the microvillous processes appears as a maze-like network of channels. The microvillous processes and the associated extracellular space are at a level just slightly higher than the level of the myoid bands. This space appears to be distinct from the basal labyrinth inasmuch as the latter extends well into the mitochondrial region of the cell, whereas the basal extracellular space does not. In places, the microvillous processes extend to the basement lamina between the myoid bands. It is postulated that the microvillous processes and the related extracellular space are associated with fluid transport and that the myoid bands may constitute a regulatory device related to the control of fluid movement.     

Correlation between testicular biopsies (prepubertal and postpubertal) and spermiogram in cryptorchid men

Twenty-one young men who underwent testicular biopsy and orchidopexy in infancy consulted owing to infertility and had biopsies again. The first and second biopsy specimens from these patients were compared by means of a semiquantitative study of the seminiferous tubules to evaluate the evolution of germ cells and to correlate these data with spermatozoon numbers. The infant testes showing lesions were classified into 3 types according to the mean tubular diameter and tubular fertility index: (1) slight lesions, (2) marked germinal hypoplasia, and (3) severe germinal hypoplasia. In the adult testes, spermatogenesis was evaluated by calculating the average numbers of spermatogonia, primary spermatocytes, young spermatids, and mature spermatids. These testes were classified as (1) normal; (2) having lesions in the adluminal compartment; (3) having lesions in the basal compartment; and (4) mixed atrophy. The number of differentiated spermatids was correlated with the expected number of spermatozoa in the ejaculate by a power regression curve. The observation of certain histologic lesions in the seminiferous tubules was assumed to indicate excretory duct obstruction: ectasia, indented outline of the seminiferous epithelium, intratesticular spermatocele, apical cytoplasmic vacuolation of Sertoli cells, and mosaic distribution of testicular lesions. There was a correlation between the prepubertal lesions and the degree of spermatogenesis in postpubertal biopsy specimens. The evolution of the 40 testes without regard to their location in infancy (cryptorchid or scrotal) was as follows. The 14 infant testes with a normal histologic pattern (5 testes) or minor lesions (9 testes) evolved to testes with lesions of the adluminal compartment (8 testes), mixed atrophy (4 testes), or lesions of the basal and adluminal compartments (2 testes). The 6 testes with marked germinal hypoplasia evolved to testes with mixed atrophy. The 20 testes with severe germinal hypoplasia evolved to testes with mixed atrophy (17 testes), Sertoli-cell-only tubules (2 testes), or lesions in the basal compartment (1 testis). In the 9 patients with a histologic pattern of obstruction bilaterally (6 men) or unilaterally (3 men), the expected number of spermatozoa according to the correlation curve was much higher than the actual number in the spermiogram. This means that the testes of many azoospermic men produce spermatozoa, and this finding corroborates the importance of testicular biopsy in infertility studies.