scholarly journals The Rete Testis: Development and Role in Testis Function

2021 ◽  
Vol 52 (6) ◽  
pp. 370-378
Author(s):  
A. Yu. Kulibin ◽  
E. A. Malolina
Keyword(s):  
Stem Cells ◽  
Sex Determination ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Rete Testis ◽  
The Other ◽  
Seminiferous Tubules ◽  
Testis Development ◽  
Stage Of Development ◽  
Efferent Ducts

Abstract The rete testis connects seminiferous tubules in which germ cells develop to the efferent ducts and the epididymis, where gametes mature and gain mobility. Several recent studies have thoroughly explored the morphogenesis of this structure in mice during embryonic and postnatal periods. A part of the rete testis has been shown to derive from the precursors of gonad somatic cells before sex determination. The other part forms from embryonal Sertoli cells of testis cords adjacent to the mesonephros. The transformation of Sertoli cells into rete testis cells is apparently not limited to the embryonic stage of development and continues during postnatal testis development. Recently, it was found that the rete testis participates in the formation and maintenance of specialized Sertoli cells in terminal segments of seminiferous tubules, transitional zones. Current views suggest that the transitional zones of the seminiferous tubules may represent a niche for spermatogonial stem cells, the site of the prolonged proliferation of Sertoli cells in the pubertal and postpubertal periods of testis development, and also could be a generator of spermatogenic waves. To sum up, the rete testis transports gametes from the testis to the epididymis, maintains pressure within seminiferous tubules, regulates the composition of the testicular fluid, and impacts the spermatogenic process itself.

Development of Testis Cords and the Formation of Efferent Ducts in Xenopus laevis: Differences and Similarities with Other Vertebrates

2021 ◽  
pp. 1-14
Author(s):  
Yuanyuan Li ◽  
Jinbo Li ◽  
Man Cai ◽  
Zhanfen Qin
Keyword(s):  
Cell Proliferation ◽  
Xenopus Laevis ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Testis Development ◽  
Larval Stages ◽  
Efferent Ducts ◽  
Steroidogenic Cells ◽  
Testis Cord ◽  
Anterior Posterior

The knowledge of testis development in amphibians relative to amniotes remains limited. Here, we used Xenopus laevis to investigate the process of testis cord development. Morphological observations revealed the presence of segmental gonomeres consisting of medullary knots in male gonads at stages 52–53, with no distinct gonomeres in female gonads. Further observations showed that cell proliferation occurs at specific sites along the anterior-posterior axis of the future testis at stage 50, which contributes to the formation of medullary knots. At stage 53, adjacent gonomeres become close to each other, resulting in fusion; then (pre-)Sertoli cells aggregate and form primitive testis cords, which ultimately become testis cords when germ cells are present inside. The process of testis cord formation in X. laevis appears to be more complex than in amniotes. Strikingly, steroidogenic cells appear earlier than (pre-)Sertoli cells in differentiating testes of X. laevis, which differs from earlier differentiation of (pre-)Sertoli cells in amniotes. Importantly, we found that the mesonephros is connected to the testis gonomere at a specific site at early larval stages and that these connections become efferent ducts after metamorphosis, which challenges the previous concept that the mesonephric side and the gonadal side initially develop in isolation and then connect to each other in amphibians and amniotes.

Histochemical localization of enzymes of various metabolic pathways in the testes of buffaloes, goats and rams

1984 ◽  
Vol 102 (2) ◽  
pp. 269-274 ◽  
Author(s):  
G. S. Bilaspuri ◽  
S. S. Guraya
Keyword(s):  
Germ Cells ◽  
Sertoli Cells ◽  
Metabolic Pathways ◽  
Maximum Activity ◽  
The Other ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Cell Type ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Enzyme Species

SummaryIsocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), glutamate dehydrogenase (GDH), β-hydroxybutyrate dehydrogenase (β-OH-BDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) were histochemically located in the testes of buffaloes, goats and rams. The enzyme activities varied with the enzyme, species and cell type. The activities in the seminiferous tubules were correlated with the stages of seminiferous epithelial cycle (SEC). During this cycle, the activities in the Sertoli cells, spermatogonia and spermatocytes remained unaltered in contrast to those in the spermatids. The activities of SDH, ICDH and MDH were relatively greater in buffalo, while goat and ram resembled each other quite closely. ICDH and MDH preferred NADP to NAD. In the three species, the activities of ICDH, SDH and MDH generally followed an increasing order. G-6-PDH was greater in the interstitial tissue of buffalo than in goat and ram; the maximum activity of this enzyme in each species was found in the spermatogonia. In comparison with G-6-PDH, GDH was less evident in the interstitial tissue of buffalo and goat; Sertoli cells and spermatogonia also showed relatively less MDH activity whereas the other germ cells may have relatively less, similar or more, GDH activity depending on the species. β-OHBDH activity was similar in the interstitial tissue of the three species, but in the seminiferous tubule, the activity was less in goat. But for GDH and β-OH-BDH which could show different results, the activities of other enzymes generally decreased from spermatogonia through spermatocytes to spermatids but increased during spermiogenesis. In spermatozoa, the enzymes were observed only in the mid-piece. The possible physiological significance of the results is discussed in relation to different metabolic pathways.

The development of the testis of the Merino ram, with special reference to the orgin of the adult stem cells

1962 ◽  
Vol 13 (3) ◽  
pp. 487 ◽  
Author(s):  
CS Sapsford
Keyword(s):  
Stem Cells ◽  
Basement Membrane ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Adult Stem Cells ◽  
Germ Line ◽  
Primordial Germ Cells ◽  
Seminiferous Tubules ◽  
Stages Of Development ◽  
Striking Change

In the ram, as in other mammals, the sex cords are made up of two types of cell: indifferent cells (derivatives of the coelomic epithelium) and primordial germ cells. In the cords, each type pursues a separate and independent line of development to become respectively the Sertoli cells and the stem cells (type A spermatogonia) of the adult testis. The principal changes taking place in the primordial germ cells (gonocytes) are a reduction in the size and number of the Feulgen-positive particles in the nuclei, the appearance and subsequent fusion of the nucleoli, and, finally, an increase in the size of the nuclei. While these changes are taking place, the cytoplasm increases in volume and inclusions become more numerous. Cells which have undergone all these transformations have been called prospermatogonia. The cells of the germ line are at first more centrally placed in the sex cords than the indifferent cells. Just before spermatogenesis begins, they migrate to the basement membrane of the seminiferous tubules. All germ cells in tubules in which spermatogenesis has been initiated are seen as prospermatogonia. These cells become flattened against the basement membrane, and their nuclei become more oval in shape. They thus become identical with the stem cells of the adult. Little change is evident in the nuclei of the indifferent cells until puberty. Feulgen-positive material is found in the form of coarse granules at earlier stages of development. At puberty, these granules become dispersed to give a much more homogeneous nucleus. Concurrently, nuclei increase in size, and single or double true nucleoli can be identified. During development, increases in cytoplasmic volume take place. Although cell boundaries between indifferent cells cannot be seen in fixed material, phase contrast observations of fresh material have demonstrated that some forms exist as mononucleate units. It could not be determined whether the same was true in the case of Sertoli cells. No striking change in the relative numbers of glandular interstitial cells could be observed at different stages of development.

scholarly journals The rete testis harbors Sertoli-like cells capable of expressing DMRT1

Reproduction ◽  
2019 ◽  
Vol 158 (5) ◽  
pp. 399-413 ◽  
Author(s):  
Ekaterina A Malolina ◽  
Andrey Yu Kulibin
Keyword(s):  
Germ Cells ◽  
Sertoli Cells ◽  
Adult Mouse ◽  
Rete Testis ◽  
Seminiferous Tubules ◽  
Rna Seq ◽  
Supporting Cells ◽  
Testicular Cells ◽  
Qpcr Analysis ◽  
Different Levels

Sertoli cells (SCs) are supporting cells in the mammalian testis that proliferate throughout fetal and postnatal development but exit the cell cycle and differentiate at puberty. In our previous study, we isolated a population of highly proliferative Sertoli-like cells (SLCs) from the region of the adult mouse testis containing the rete testis and adjacent seminiferous tubules. Here RNA-seq of the adult SLC culture as well as qPCR analysis and immunofluorescence of the adult and immature (6 dpp) SLC cultures were performed that allowed us to identify SLC-specific genes, including Pax8, Cdh1, and Krt8. Using these, we found that SLCs are mostly localized in the rete testis epithelium; however, some contribution of transitional zones of seminiferous tubules could not be excluded. The main feature of SLCs indicating their relationship to SCs is DMRT1 expression. More than 40% of both adult and immature SLCs expressed DMRT1 at different levels in culture. Only rare DMRT1+ cells were detected in the adult rete testis, whereas more than 40% of cells were positively stained for DMRT1 in the immature rete testis. One more SC protein, AMH, was found in some rete cells of the immature testis. It was also demonstrated that SLCs expressed such SC genes as Nr5a1, Dhh, Gdnf, and Kitl and interacted with germ cells in 3D co-culture with immature testicular cells. All these similarities between SLCs and rete cells on one the hand and SCs on the other, suggest that rete cells could share a common origin with SCs.

324 TESTIS-SPECIFIC EXPRESSION OF Oct4-EGFP TRANSGENE IN PIG

2015 ◽  
Vol 27 (1) ◽  
pp. 251
Author(s):  
M. Nowak-Imialek ◽  
N. Lachmann ◽  
D. Herrmann ◽  
F. Jacob ◽  
H. Niemann
Keyword(s):  
Stem Cells ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Leydig Cells ◽  
Egfp Expression ◽  
Seminiferous Tubules ◽  
Marker Genes ◽  
Specific Expression ◽  
Oct4 Expression ◽  
Egfp Reporter

Oct4 is a transcription factor essential for establishment and maintenance of pluripotency in mammalian stem cells. Oct4 expression was found in early embryos and germ cells throughout fetal development. In male mice, Oct4 expression is found in mitotically arrested prospermatogonia until birth. After onset of spermatogenesis, expression is maintained in type A spermatogonia, but is downregulated in type B spermatogonia and in spermatocytes (Pesce et al. 1998 Mech. Dev). Previously, we successfully generated Oct4-EGFP reporter pigs carrying the entire 18-kb genomic sequence of the murine Oct4 gene fused to the enhanced green fluorescent protein (EGFP) cDNA (Nowak-Imialek et al. 2011 Stem Cells Dev.). This animal model is unique because it allows in vivo and in vitro visualisation of Oct4-positive cells. Germ line specific Oct4-EGFP expression was analysed in testis isolated from young (<1 week) and adult (>7 months) pigs. Squash preparation of testicular tissue isolated from adult transgenic boars revealed high amounts of EGFP-positive cells compared to young piglets. We confirmed Oct4 and EGFP expression in the testis from young and adult transgenic animals using Northern blot analysis. Specific expression of Oct4 and EGFP in testis could be observed in blots as a single band of 1.5 kb. As a loading control, the blot was rehybridized with a β-actin probe. Mammalian testes contain different cell types, including germ cells, Sertoli cells, Leydig cells, and peritubular cells. To define the cellular origin of EGFP-expressing cells, we isolated these cells from adult transgenic testis using fluorescence-activated cell sorting (FACS)-based techniques. Analysis of isolated EGFP positive cells with qRT-PCR demonstrated the presence of marker genes specific for undifferentiated (Oct4, UTF1, FGFR3, PGP 9.5, THY-1, SALL4, and GFRα1) and differentiated (BOLL and PRM2) germ cells. Markers specific for Sertoli cells (vimentin) and Leydig cells (LHCGR) were not observed. To verify the localization of EGFP-positive cells in seminiferous tubules, we performed immunohistochemical detection of GFP in adult pig testis. Unlike the Oct4-EGFP reporter mouse model, GFP protein was not found in spermatogonia attached to the basement membrane of seminiferous tubules, but instead were found in differentiated germ cells, including spermatocytes and spermatids. These results show that the Oct4-EGFP expression in testis differs between mouse and porcine Oct4-EGFP transgenic models. To verify that the EGFP expression driven by the mouse Oct4 promoter in porcine testis reflects the endogenous Oct4 expression profile, Western blot and histochemical analyses are currently underway.

288 THE EXPRESSION PATTERN OF ACETYLATED ALPHA-TUBULIN IS CONSERVED IN PORCINE AND MURINE SPERMATOGONIAL STEM CELLS

2008 ◽  
Vol 20 (1) ◽  
pp. 223
Author(s):  
J. Luo ◽  
S. Megee ◽  
I. Dobrinski
Keyword(s):  
Stem Cells ◽  
Basement Membrane ◽  
Expression Pattern ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Spermatogonial Stem Cells ◽  
Seminiferous Tubules ◽  
Histone Deacetylase 6 ◽  
Pgp 9.5

During mammalian spermatogenesis, spermatogonial stem cells (SSCs) reside in the stem cell niche on the basement membrane where they undergo self-renewing divisions. Differentiating daughter cells are located progressively more toward the tubular lumen where they ultimately form spermatozoa. The mechanisms responsible for maintenance of SSCs at the basement membrane are unclear. Microtubules consisting of α/β-tubulin heterodimers are associated with many cellular functions. Reversible acetylation of α-tubulin at Lys40 has been implicated in regulating microtubule stability and function. Acetylation of α-tubulin is abundant in stable microtubules but absent from dynamic cellular structures. Deacetylation of α-tubulin is controlled by histone deacetylase 6 which is predominantly expressed in mouse testis. Here, we tested the hypothesis that differential acetylation of α-tubulin might be involved in maintenance of SSCs. Immunohistochemistry for acetylated α-tubulin (Ac-α-Tu) and the spermatogonia specific proteins PGP 9.5, DAZL, and PLZF were used to characterize the expression pattern of Ac-α-Tu in porcine and murine germ cells at different stages of testis development. In immature boar testes, Ac-α-Tu was present exclusively in gonocytes but not in other testicular cells at 1 week of age, and in a subset of spermatogonia at 10 weeks of age. At this age, spermatogonia are migrating to the basement membrane of the seminiferous tubules, and Ac-α-Tu appeared to be polarized toward the basement membrane. In immature mouse testes, Ac-α-Tu was present in germ cells and Sertoli cells at 6 days of age, whereas at 2 weeks of age, Ac-α-Tu expression was stronger in spermatogonia co-expressing PGP 9.5 and in spermatocytes than in Sertoli cells or PGP 9.5-negative spermatogonia. In adult boar and mouse testes, Ac-α-Tu was detected in a few single or paired spermatogonia expressing PGP 9.5 localized on the basement membrane as well as in spermatocytes, spermatids, and spermatozoa. Spermatogonia with high levels of Ac-α-Tu expressed PLZF but did not express DAZL, suggesting that only undifferentiated spermatogonia maintain a high level of Ac-α-Tu. When seminiferous tubules from 1-week-old and adult boar testes were maintained in vitro for 1–2 days, high levels of Ac-α-Tu were detected in single or paired round spermatogonia with a large nucleus, compared to low levels in elongated paired and aligned spermatogonia. The unique expression pattern of Ac-α-Tu in undifferentiated germ cells during postnatal development appears to be conserved in mammalian testes. Since Ac-α-Tu is a component of long-lived stable microtubules and reducing acetylation of α-tubulin enhances cell motility, these results suggest that stabilization of microtubules might contribute to the maintenance of spermatogonial stem cells. This work was supported by 1R01 RR 17359-05.

scholarly journals PSII-36 The application of busulfan to inhibit the spermatogenesis in quail testis

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 373-373
Author(s):  
Tatyana Kotova ◽  
Anastasia N Vetokh ◽  
Ludmila A Volkova ◽  
Natalia Volkova ◽  
Natalia A Zinovieva
Keyword(s):  
Stem Cells ◽  
Body Weight ◽  
Germ Cells ◽  
Genetic Modification ◽  
Sertoli Cells ◽  
Seminiferous Tubules ◽  
Multiple Injection ◽  
Spermatogenic Cells ◽  
Methodological Approaches ◽  
Spermatogonia Cells

Abstract The use of testicular stem cells (spermatogonia) is of most interest for obtaining individuals with predetermined traits and genome genetic modification and for conservation of poultry gene pool. A significant population of mature donor germ cells (sperm) is formed upon successful spermatogonia cells transplantation into the testes of male recipients. Obtained sperm can be used to produce offspring with the desired traits. A key step in this technology is the removal of own spermatogenic cells (inhibition of spermatogenesis) in male recipients. The aim of research was to develop and optimize methodological approaches to inhibit the spermatogenesis in quail using busulfan. This drug was injected directly into the testes parenchyma of mature males by multiple injection at the concentration from 20 to 100 mg per 1kg of body weight (n = 25). Histological preparations of testes from the experimental quails were obtained to study composition of spermatogenic cells in the seminiferous tubules after busulfan administration. The male peers who were not injected with busulfan were used as a control. Experimental quails showed a decrease in the number of spermatogenic cells in the seminiferous tubules 32, 75, 111, 119 and 118 times compared with the control when using busulfan in concentrations 20, 40, 60, 80 and 100 mg/kg of weight, respectively (P &lt; 0.001). The cells composition in the seminiferous tubules from experimental quails was represented mainly by Sertoli cells and spermatogonia. After busulfan introduction at the concentrations 20, 40, 60, 80 and 100 mg/kg, the percentage of spermatogonia was 55±5 %, 24±4 %, 6±2 %, 5±2 % and 4±1 %, respectively. The use of busulfan at the concentration of 80–100 mg/kg led to high mortality of quails. Thus, it was found that the optimal busulfan concentration for elimination of quail spermatogenic cells was 60 mg/kg. Supported by RFBR within Project №18-29-07079.

scholarly journals Stem Cell Therapy for Male Infertility: A Review

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Nathan Isaac Dibal ◽  
Musa Samaila Chiroma ◽  
Martha Orendu Attah
Keyword(s):  
Stem Cells ◽  
Germ Cells ◽  
Continuous Production ◽  
Genetic Material ◽  
Spermatogonial Stem Cells ◽  
Rete Testis ◽  
Reproductive Age ◽  
Seminiferous Tubules ◽  
Male Factor ◽  
Induced Pluripotent

Infertility affects 15% of couples in reproductive age world-wide and male factor is solely responsible in about 50% of the cases and contributory in 30-40% of cases. Spermatogonial stem cells (SSCs) are small self-renewing cells found in the basal compartment of seminiferous tubules where they form the foundation of spermatogenesis and are required for the continuous production of sperm. Transplantation of spermatogonial stem cells results in a donor derived sperm production and fertility in rodent and non-rodent species like Goat. Transplantation of cryopreserved spermatogonial stem cells could help oncology patients undergoing radiotherapy or chemotherapy by prior isolation of the SSCs and transplantation after treatment. Induced pluripotent stem cells also have the ability to differentiate into late stage germ cells. The efficacy and safety of SSCs transplantation showed that offspring produced did not show any morphological differences or alteration of genetic material but is most effective through assisted reproduction and better on young/immature Animals. The transfer of germ cells through micro-injection of seminiferous tubules and cannulation of efferent ducts is most effective on rodent testis while injection into the rete testis guided by ultrasound was reported to be the best technique in higher Animals (Bulls and Apes). Researches are still ongoing to get a safe and successful method of SSCs transplantation with no or less side effects on humans.Keywords: Cryopreserved, Pluripotent, self-renewing, Spermatogonia, and Spermatogenesis

Male Reproductive Function

2011 ◽  
Author(s):  
William J. Kovacs
Keyword(s):  
Tight Junctions ◽  
Sertoli Cell ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Leydig Cells ◽  
Reproductive Function ◽  
Rete Testis ◽  
Seminiferous Tubules ◽  
Male Reproductive Function ◽  
Peritubular Tissue

The testes are the source of both germ cells and hormones essential for male reproductive function. The production of both sperm and steroid hormones is under complex feedback control by the hypothalamic-pituitary system. The testis consists of a network of tubules for the production and transport of sperm to the excretory ducts and a system of interstitial cells (called Leydig cells) that express the enzymes required for the synthesis of androgens. The spermatogenic or seminiferous tubules are lined by a columnar epithelium composed of the germ cells themselves as well as supporting Sertoli cells surrounded by peritubular tissue made up of collagen, elastic fibers, and myofibrillar cells. Tight junctions between Sertoli cells at a site between the spermatogonia and the primary spermatocyte form a diffusion barrier that divides the testis into two functional compartments, basal and adluminal. The basal compartment consists of the Leydig cells surrounding the tubule, the peritubular tissue, and the outer layer of the tubule containing the spermatogonia. The adluminal compartment consists of the inner two-thirds of the tubules containing primary spermatocytes and germ cells in more advanced stages of development. The base of the Sertoli cell is adjacent to the basement membrane of the spermatogenic tubule, with the inner portion of the cell engulfing the developing germ cells so that spermatogenesis actually takes place within a network of Sertoli cell cytoplasm. The mechanism by which spermatogonia pass through the tight junctions between Sertoli cells to begin spermatogenesis is unknown. The close proximity of the Leydig cell to the Sertoli cell with its embedded germ cells is thought to be critical for normal male reproductive function. The seminiferous tubules empty into a network of ducts termed the rete testis. Sperm are then transported into a single duct, the epididymis. Anatomically, the epididymis can be divided into the caput, the corpus, and the cauda regions. The caput epididymidis consists of 8 to 12 ductuli efferentes, which have a larger lumen tapering to a narrower diameter at the junction of the ductus epididymidis.

Sex chimaerism, fertility and sex determination in the mouse

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 311-325 ◽  
Author(s):  
C.E. Patek ◽  
J.B. Kerr ◽  
R.G. Gosden ◽  
K.W. Jones ◽  
K. Hardy ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sertoli Cells ◽  
Leydig Cells ◽  
Sex Chromosome ◽  
Tunica Albuginea ◽  
In Situ Hybridisation ◽  
Ovarian Surface Epithelium ◽  
Surface Epithelium ◽  
Seminiferous Tubules ◽  
Coelomic Epithelium

Adult intraspecific mouse chimaeras, derived by introducing male embryonal stem cells into unsexed host blastocysts, were examined to determine whether gonadal sex was correlated with the sex chromosome composition of particular cell lineages. The fertility of XX in equilibrium XY and XY in equilibrium XY male chimaeras was also compared. The distribution of XX and XY cells in 34 XX in equilibrium XY ovaries, testes and ovotestes was determined by in situ hybridisation using a Y-chromosome-specific probe. Both XX and XY cells were found in all gonadal somatic tissues but Sertoli cells were predominantly XY and granulosa cells predominantly XX. The sex chromosome composition of the tunica albuginea and testicular surface epithelium could not, in general, be fully resolved, owing to diminished hybridisation efficiency in these tissues, but the ovarian surface epithelium (which like the testicular surface epithelium derives from the coelomic epithelium) was predominantly XX. These findings show that the claim that Sertoli cells were exclusively XY, on which some previous models of gonadal sex determination were based, was incorrect, and indicate instead that in the mechanism of Sertoli cell determination there is a step in which XX cells can be recruited. However, it remains to be established whether the sex chromosome constitution of the coelomic epithelium lineage plays a causal role in gonadal sex determination. Male chimaeras with XX in equilibrium XY testes were either sterile or less fertile than chimaeras with testes composed entirely of XY cells. This impaired fertility was associated with the loss of XY germ cells in atrophic seminiferous tubules. Since this progressive lesion was correlated with a high proportion of XX Leydig cells, we suggest that XX Leydig cells are functionally defective, and unable to support spermatogenesis.

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