Unilateral cryptorchidism induces morphological changes of testes and hyperplasia of Sertoli cells in a dog

Anti-Müllerian hormone in feline cryptorchidism: Serum levels, tissue expression, and implications for testicular health

Anti-Müllerian hormone (AMH) has become a pivotal subject in the study of testicular descent, maturation, integrity, and male fertility. Recent studies explored its roles and implications across various domestic species. A prominent approach involved the understanding of the modulation of AMH in reproductive disorders, including cryptorchidism. While substantial findings have been reported in dogs, ruminants, swine, and horses, data on AMH in feline cryptorchidism remains limited. Here, we aimed to bridge this gap by comparing AMH serum levels among cryptorchid, healthy intact, and castrated tomcats, employing an enzyme-linked immunosorbent assay (ELISA) kit for quantification. In addition, AMH expression in retained and descended testes was evaluated through immunohistochemistry, with positive staining quantified via pixel analysis in two distinct regions of interest: the seminiferous tubule and the interstitial space. Furthermore, tissue samples were subjected to histological evaluation and morphometric analysis, which included the calculation of seminiferous tubule areas (STA) and assessment of Johnsen scores. Thus, the relationship between AMH expression, altered testicular histology, and impaired spermatogenesis could be examined. The expression of AMH in retained and descended testes, was investigated, and the relationship between AMH expression, altered testicular histology, and impaired spermatogenesis was examined. Mean serum AMH levels differed significantly (P < 0.001) across the different groups being 15.35 ± 4.66 ng/mL (mean ± SD) in healthy intact tomcats (n = 15), 25.55 ± 2.86 ng/mL (mean ± SD) in cryptorchids (n = 10) and below 0.015 ng/mL in castrated cats (n = 10). STAs and Johnsen scores were significantly reduced in retained testes when compared to descended gonads (P < 0.01). Furthermore, serum AMH was negatively correlated with both the STA (ρ = -0.725, P < 0.001) and the Johnsen scores (ρ = -0.699, P < 0.001), suggesting its potential value for tissue integrity and spermatogenesis evaluation. In addition, positive immunostaining was significantly higher in retained testes (P < 0.05), especially in the interstitial space (P < 0.01), suggesting an involvement of the Leydig cells. Additionally, the increased interstitial expression was linked to the degree of tissue degeneration and the impaired spermatogenesis being negatively corelated with both Johnsen scores (ρ = -0.309, P < 0.01) and STA (ρ = -0.208, P < 0.05). Our findings underscore the potential of AMH in assessing testicular health and reveal possible interspecific differences, stressing the need for further investigation in cats.

Exploring Testicular Descent: Recent Findings and Future Prospects in Canine Cryptorchidism

BACKGROUND

Canine cryptorchidism, manifested by an abnormal testicular position, poses significant health risks and reproductive challenges in affected males. Despite a high prevalence, estimated at up to 10% in the canine population, a comprehensive understanding of its pathogenesis remains elusive. Studies in human cryptorchids and knockout mice have identified key factors involved in testicular descent, including INSL3, RXFP2, and AR. To date, only three DNA variants, found in the RXFP2, HMGA2, and KAT6A genes, have been associated with canine cryptorchidism.

SUMMARY

This review briefly summarizes current knowledge on testicular descent and the factors that regulate this process, based on cryptorchidism in humans and mice. It also highlights recent findings related to canine cryptorchidism, focusing on the INSL3, HMGA2, and KAT6A genes. The most significant results are discussed, with an emphasis on the role of the epididymis in testicular descent. This report presents insights that may facilitate further research aiming to broaden our understanding of canine cryptorchidism pathogenesis.

KEY MESSAGES

DNA polymorphism in the KAT6A gene, associated with changes in global H3K9 acetylation, as well as the DNA methylation pattern in the INSL3 gene, suggest that further research should strongly focus on epigenetic modifications. In addition, the development of the epididymo-testicular junction and the link between cryptorchidism prevalence and dog size should be further investigated.

Anti-Müllerian hormone as a diagnostic marker for testicular degeneration in dogs: insights from cryptorchid models

Introduction

The increasing prevalence of infertility in male dogs in clinical practice mirrors current trends seen in human medicine. Acquired infertility is notably more common in dogs compared to congenital causes, with conditions such as testicular degeneration leading to irreversible loss of fertility. Current diagnostic methods for testicular degeneration, such as histopathological and cytological examinations, rely on testicular biopsy or fine needle aspiration, making them less feasible for routine use. Anti-Müllerian hormone (AMH), produced by Sertoli cells, has emerged as a potential alternative biomarker for testicular health, which can be measured in serum. This study evaluates AMH as a potential marker for testicular degeneration, using cryptorchid dogs as models for impaired fertility and altered testicular histology.

Methods

The relationship between serum AMH levels and AMH tissue expression with impaired spermatogenesis and altered histology was investigated. Serum AMH levels were determined in intact, cryptorchid, and castrated individuals using an immuno-enzymatic ELISA kit and compared between subgroups based on testicular location. Tissue AMH immuno-expression was differentially quantified in two regions of interest (ROIs), the interstitial space and the seminiferous tubule, in both descended and retained gonads. Furthermore, testicles were analyzed using histomorphometric analysis in seminiferous tubules, while spermatogenesis was evaluated using the Johnsen score.

Results

Serum AMH levels were positively correlated with AMH expression assessed in both interstitial space (ρ = 0.494, p ≤ 0.01) and seminiferous tubules (ρ = 0.610, p ≤ 0.001). Conversely, serum AMH levels showed a negative correlation with the seminiferous tubule area (ρ = -0.435, p ≤ 0.05). Smaller seminiferous tubule areas were linked to increased AMH reactivity in both seminiferous tubules (ρ = -0.774, p ≤ 0.001) and interstitial space (ρ = -0.725, p ≤ 0.001). Additionally, lower Johnsen scores were associated with higher serum AMH levels (ρ = -0.537, p ≤ 0.01) and elevated AMH expression in both seminiferous tubules (ρ = -0.756, p ≤ 0.001) and interstitial space (ρ = -0.679, p ≤ 0.001).

Discussion

Our results suggest that higher serum levels and tissue expression of AMH are linked to smaller seminiferous tubules and poorer Johnsen scores, reflecting degenerative changes and Sertoli cell dysfunction in retained testicles. Given the similarities in the mechanisms that increase AMH levels in both cryptorchid and non-cryptorchid testicles affected by testicular degeneration, this study recommends using AMH as a marker for diagnosing testicular degeneration in dogs.

Cryptorchidism and testicular cancer in the dog: unresolved questions and challenges in translating insights from human studies†

Cryptorchidism, the failure of one or both testes to descend into the scrotum, and testicular cancer show a strong correlation in both dogs and humans. Yet, long-standing medical debates persist about whether the location of undescended testes directly causes testicular cancer in humans or if both conditions stem from a common origin. Although testicular cancer is a prevalent disease in dogs, even less is known about its cause and correlation with testicular descent in this species. This review investigates the relation between these two disorders in dogs, drawing insights from human studies, and examines key biomarkers identified thus far. In addition, it explores potential causal links, including the impact of temperature on maturing testicular cells and a potential shared genetic origin. Notably, this literature review reveals significant differences between men and dogs in reproductive development, histological and molecular features of testicular tumors, and the prevalence of specific tumor types, such as Sertoli cell tumors in cryptorchid dogs and germ cell tumors in humans. These disparities caution against using dogs as models for human testicular cancer research and underscore the limitations when drawing comparisons between species. The paper concludes by suggesting specific research initiatives to enhance our understanding of the complex interplay between cryptorchidism and testicular cancer in dogs.

G Protein-Coupled Estrogen Receptor (GPER) and ERs Are Modulated in the Testis-Epididymal Complex in the Normal and Cryptorchid Dog

There is growing evidence by the literature that the unbalance between androgens and estrogens is a relevant condition associated with a common canine reproductive disorder known as cryptorchidism. The role of estrogens in regulating testicular cell function and reproductive events is supposedly due to the wide expression of two nuclear estrogen receptors (ERs), ER-alpha and ER-beta and a trans-membrane G protein-coupled estrogen receptor (GPER) in the testis. In this study, immunohistochemistry, Western blotting and qRT-PCR were used to assess the distribution and expression of GPER in the testis-epididymal complex in the normal and cryptorchid dog. ER-alpha and ER-beta were also evaluated to better characterize the relative abundances of all three receptors. In addition, in these tissues, the expression level of two proteins as SOD1 and Nrf2 normally associated with oxidative stress was investigated to evaluate a possible relationship with ERs. Our data revealed changes in the distribution and expression of the GPER between the normal and cryptorchid dog. In particular, dogs affected by cryptorchidism showed an upregulation of GPER at level of the examined reproductive tract. Also considering the obtained result of a modulation of SOD1 and Nrf2 expression, we could hypothesize the involvement of GPER in the cryptorchid condition. Further studies are, however, necessary to characterize the role of GPER and its specific signaling mechanisms.

Potential role of inducible nitric oxide synthase (iNOS) activity in testicular dysfunction following co-administration of alcohol and combination antiretroviral therapy (cART) in diabetic rats: an immunohistochemistry study

Diabetes, alcohol abuse, and combination antiretroviral therapy (cART) use have been reported to cause multi-organ complications via induction of oxidative stress and inflammation. Moreover, these are the most common factors implicated in male reproductive dysfunctions. This study evaluated testicular oxidative stress, inflammation, apoptosis, and germ cell proliferation in diabetic rats receiving alcohol or cART and their combination. Thirty adult male Sprague Dawley rats were divided into five groups, each consisting of six rats; control, diabetic only (DM), diabetic treated with alcohol (DM + A), diabetic treated with cART (DM + cART), and diabetic treated with both alcohol and cART (DM + A + cART). After 90 days of treatment, the rats were terminated, and the testes were extracted and processed for immunohistochemistry analysis for oxidative stress, inflammatory cytokines, apoptosis, and cell proliferation marker. In comparison to the control, oxidative stress markers, inducible nitric oxide synthase (iNOS), malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHDG) increased significantly in all treated groups. Expression of testicular proinflammatory cytokines, interleukin-1β, and tumor necrosis factor-α was upregulated in all treated groups, but interleukin-6 was upregulated in DM, DM + cART, and DM + A + cART treated groups and was downregulated in the DM + A treated group. All treated animal groups showed an upregulation of apoptotic marker (caspase 3) and a downregulation of proliferation marker (Ki-67). However, Ki-67 staining intensity significantly increased in treated animals compared to the control. These findings suggest that diabetes, alcohol abuse, cART use, and their combination via iNOS activity upregulation can induce inflammation and oxidative stress in testicular tissue, stimulating germ cell apoptosis and proliferation inhibition leading to failure of spermatogenesis.

Crucial Roles of the Mesenchymal Androgen Receptor in Wolffian Duct Development

Wolffian duct (WD) maintenance and differentiation is predominantly driven by the androgen action, which is mediated by the androgen receptor (AR). It is well established that the mesenchyme indicates the fate and differentiation of epithelial cells. However, in vivo developmental requirement of mesenchymal AR in WD development is still undefined. By designing a mesenchyme-specific Ar knockout (ARcKO), we discovered that the loss of mesenchymal Ar led to the bilateral or unilateral degeneration of caudal WDs and cystic formation at the cranial WDs. Ex vivo culture of ARcKO WDs invariably resulted in bilateral defects, suggesting that some factor(s) originating from surrounding tissues in vivo might promote WD survival and growth even in the absence of mesenchymal Ar. Mechanistically, we found cell proliferation was significantly reduced in both epithelial and mesenchymal compartments; but cell apoptosis was not affected. Transcriptomic analysis by RNA sequencing of E14.5 mesonephroi revealed 131 differentially expressed genes. Multiple downregulated genes (Top2a, Wnt9b, Lama2, and Lamc2) were associated with morphological and cellular changes in ARcKO male embryos (ie, reduced cell proliferation and decreased number of epithelial cells). Mesenchymal differentiation into smooth muscle cells that are critical for morphogenesis was also impaired in ARcKO male embryos. Taken together, our results demonstrate the crucial roles of the mesenchymal AR in WD maintenance and morphogenesis in mice.

Anti-Müllerian hormone levels in serum and testes of male dogs: relations with neuter status and bilateral abdominal cryptorchidism

Anti-Müllerian hormone (AMH) analysis has contributed to new information in the reproductive endocrinology of domestic animals, due to clinically available diagnostic tools. An accurate and rapid diagnostic method to distinguish between neutered and bilateral abdominal cryptorchid dogs is needed in veterinary practice. Therefore, this study uses an enzyme-linked immunosorbent assay to evaluate the clinical relevance of AMH analysis in peripheral blood as a diagnostic tool for dogs with suspected bilateral abdominal cryptorchidism. The possible alteration of the AMH localization in testicular tissue caused by this pathologic condition was also investigated using immunohistochemistry. Male dogs were divided into three groups of healthy intact (n = 14), healthy castrated (n = 14), and bilateral abdominal cryptorchid (n = 14) dogs. The results demonstrated a higher level of serum AMH in the cryptorchid group compared to the intact group (P < 0.01), while serum AMH levels of all castrated dogs were below the limit of detection (<0.05 ng/mL). Moreover, the percentage of positive AMH immunostaining of the intact group was less than that of the cryptorchid group (P < 0.01). A significantly positive correlation was found between serum AMH concentration and localization in testicular tissues (r = 0.93, P < 0.01). Our findings suggest that AMH levels in the peripheral blood could be used as an alternative and rapid screening method for detecting dogs with abdominal cryptorchidism.

Loss of WNT4 in the gubernaculum causes unilateral cryptorchidism and fertility defects

Undescended testis (UDT) affects 6% of male births. Despite surgical correction, some men with unilateral UDT may experience infertility with the contralateral descended testis (CDT) showing no A-dark spermatogonia. To improve our understanding of the etiology of infertility in UDT, we generated a novel murine model of left unilateral UDT. Gubernaculum-specific Wnt4 knockout (KO) mice (Wnt4-cKO) were generated using retinoic acid receptor β2-cre mice and were found to have a smaller left-unilateral UDT. Wnt4-cKO mice with abdominal UDT had an increase in serum follicle-stimulating hormone and luteinizing hormone and an absence of germ cells in the undescended testicle. Wnt4-cKO mice with inguinal UDT had normal hormonal profiles, and 50% of these mice had no sperm in the left epididymis. Wnt4-cKO mice had fertility defects and produced 52% fewer litters and 78% fewer pups than control mice. Wnt4-cKO testes demonstrated increased expression of estrogen receptor α and SOX9, upregulation of female gonadal genes, and a decrease in male gonadal genes in both CDT and UDT. Several WNT4 variants were identified in boys with UDT. The presence of UDT and fertility defects in Wnt4-cKO mice highlights the crucial role of WNT4 in testicular development.

Immunohistochemical insights into a hidden pathology: Canine cryptorchidism

Cryptorchidism is a common disorder in the canine population with some aspects still unclear. Although the bilateral condition is known to lead to fertility problems and predisposition to testicular cancer, the neoplastic risk for scrotal testis in unilateral cryptorchid dog is controversial. Therefore, the therapeutic approach to the canine unilateral cryptorchid is arbitrary so far. This study aimed to investigate precancerous testicular lesions, such as immaturity and atrophy, and compare them in scrotal and undescended testes using an in-depth diagnostic analysis based on immunophenotypic patterns. With this purpose, 26 adult male dogs of different ages and breeds, affected by unilateral or bilateral cryptorchidism were enrolled. After surgical removal, testes were examined immunohistochemically to assess their positivity for specific markers of the canine foetal/neonatal period, that is vimentin (VIM), cytokeratin (CK), desmin (DES), inhibin-α (INH), and anti-Müllerian hormone (AMH) in Sertoli cells, and placental alkaline phosphatase (PLAP) in germ cells. Except for the ubiquitous VIM, all the markers were more expressed in neoplastic gonads compared to healthy ones (P < 0.05). Similarly, testes detected with Sertoli cell-only tubules as well as with Sertoli cells hyperplasia showed higher expression than gonads without such alterations for CK, DES, AMH and PLAP, and for CK and DES, respectively (P < 0.05). The same trend was observed in undescended respect to scrotal testes even though their positivity was significant only for DES, INH and AMH (P < 0.05). Immunohistochemical positivity found in scrotal testes of unilateral cryptorchid dogs, even in absence of detectable anatomical abnormalities, was suggestive of precancerous lesions. Despite the limited sample size, this study could help to clarify the predisposition to neoplastic development in normally descended testes. These markers expression in adult life could allow identifying the early stages of the testicular carcinogenesis process besides suggesting a precautionary bilateral surgical approach in unilateral cryptorchid dogs.

Effect of Cryptorchidism on the Histomorphometry, Proliferation, Apoptosis, and Autophagy in Boar Testes

Simple Summary

Body temperature has detrimental effects on sperm quality in mammalian species, including pigs. However, the molecular mechanism of this is not yet well understood. Cryptorchidism is when one or both testes fail to descend into the scrotum, which leads the testes to be exposed to the body temperature. The aims of present study were to investigate the effect of body temperature on the histomorphometry, apoptosis and the expression of the proliferation-associated protein PCNA and the autophagy-associated protein LC3 in spontaneous unilateral cryptorchid boar testes. Our findings showed that cryptorchidism had no evident influence on the number of Sertoli cells in boars. In cryptorchid testes, spermatogonia markedly decreased and the seminiferous tubule contained only a few spermatogonia, but did not contain post-meiotic germ cells. The altered seminiferous epithelium of the cryptorchid testis showed a low proliferation of its spermatogonia, with apoptosis and autophagy like that of scrotal testis, which probably entailed a gradual degeneration of the epithelium and the impossibility of its recovery. Although the number of Sertoli cells did not change, it was likely that their functionality was altered and that this affected the proliferation capacity of spermatogonia, causing the arrest of spermatogenesis.

Abstract

Spontaneous unilateral cryptorchid boars have one testis in the abdomen or inguinal canal, causing its temperature to be at or near the body temperature, which impairs spermatogenesis, although the histomorphometry and molecular mechanisms underlying this process remain unclear. The aim of the present study was to determine the histomorphometry, proliferation, apoptosis, and autophagy alterations in spermatogonia and Sertoli cells in unilateral cryptorchid, scrotal (contrascrotal), and preweaning piglet (preweaning) testes. Histomorphometrical analysis of cryptorchid testes showed that the seminiferous tubules contained only Sertoli cells and a few spermatogonia, but did not contain post-meiotic germ cells. The number of spermatogonia markedly decreased, and the number of Sertoli cells did not change remarkably in cryptorchid testes. TUNEL assay results showed that apoptosis signals were predominantly observed in spermatogonia. In cryptorchid and contrascrotal testes, proliferating cell nuclear antigen (PCNA) and LC3 were located in spermatogonia. The number of PCNA-positive, TUNEL-positive, and LC3-positive germ cells was low, and the protein and mRNA levels of PCNA and LC3 were significantly decreased in cryptorchid testes. Taken together, the number of Sertoli cells did not change remarkably, whereas the number of germ cells decreased in the cryptorchid testes, compared with that in the contrascrotal testes. Insufficient proliferation, excessive apoptosis, and autophagy were involved in the regulation of the decrease in spermatogonia in cryptorchid boar testes.

Senescence and adiponectin signaling - Studies in canine testis

BACKGROUND

The meaning of senescence for tissue physiological and pathological conditions is poorly known. Based on initial reports especially proteins and mechanisms that regulate this process are necessary to be determinate.

METHODS

The main aim of the study was to investigate the presence of senescent cells in canine testicular tissue (mixed breed testes; n = 60) in relation to adiponectin signaling. In detail, new information on the senescence cell number, as well as senescence and adiponectin signaling mechanisms in cryptorchid and germ cell tumor testes were provided with the use of immunohistochemical and colorimetric analyses.

RESULTS

Comparison of immunohistochemical results, in cryptorchid and tumor testes revealed increased number of senescent cells (p16 and γH2AX markers). Increased expression of adiponectin and adiponectin receptor 1, as well as extracellular signal-activated kinase (ERK1/2) in pathological testes were detected. In addition, decreased cholesterol and increased testosterone levels in tumor testis were found.

CONCLUSION

The present study is the first to demonstrate the presence as well as the differences that exist in senecent cell number in mixed breed dog testes with cryptorchidism and germ cell tumor. Altered expression of adiponectin signaling and ERK1/2 signaling pathways together with altered cholesterol and testosterone levels reflect important senescence role in disturbed functions of canine testis. Moreover, the application of studied here senescence regulating molecules for detection and prevention against pathologies of the male gonad should be furtherly considered.

Autophagy is increased in cryptorchid testis resulting in abnormal spermatozoa

Autophagy is involved in spermatogenesis by regulating germ cell maturation. This catabolic process increases with hyperthermic conditions to prevent the accumulation of damaged organelles. Cryptorchidism is associated with impairment of germ cell maturation revealed by the presence of immature forms of sperm cells in ejaculates. The aim of the present study was to evaluate the status of autophagy in sperm cells from cryptorchid patients. Semen samples of cryptorchid patients and normozoospermic controls were analyzed by immunocytochemistry and electron microscopy. Autophagy proteins, autophagy-related protein 9 (ATG9) and microtubule-associated protein, 1A/1B-light chain 3 (LC3) were localized by immunocytochemistry on the acrosome and on the equatorial segment of sperm cells. LC3 was also detected in the midpiece of cryptorchid sperm tail. Autophagy substrate p62 protein was present in the acrosome and in the postequatorial segment of sperm in control samples, but not in the cryptorchid ones. Transmission electron microscopy revealed double-membrane-limited autophagosomes in postequatorial part of spermatozoa head and midpiece in cryptorchid samples. Partly degraded mitochondria were frequently discerned in autophagic vacuoles. In conclusion, autophagy is increased in sperm cells from patients with cryptorchid history comparatively to control. Our work provides insights into the role of autophagy in the maturation and survival of human male gametes in pathological conditions. Thus, regulating autophagy could represent a potential way to improve sperm quality in cryptorchid men.

Urocortinergic system in the epididymis of the normal and cryptorchid dogs

Cryptorchidism is associated with changes in the gonads and the spermatic duct system, which may cause infertility problems. Urocortin (UCN) is a corticotrophin-releasing hormone (CRH)-related peptide, which affects several functions of male genital organs. The aim of the present study was to investigate the expression of UCN and its receptors CRHR1 and CRHR2 using immunohistochemistry, western blotting and real-time reverse transcription polymerase chain reaction in tissues collected from the epididymis of normal and cryptorchid dogs. The lumen of the cryptic epididymal duct was found to be relatively smaller than that of the normal one, and interstitial tissue was abundant in the cryptic epididymis. In addition, only a few spermatids were observed in the lumen of the epididymal duct. Results showed that UCN, CRHR2 and CRHR1 were expressed in tissues collected from normal and cryptic epididymal ducts. Urocortin- and CRHR2-immunoreactivities (IRs) were detected in the principal cells of the caput, corpus and cauda of the normal and cryptic epididymides. CRHR1-IR was detected in vascular smooth muscles and fibromuscular cells surrounding epididymal tubules of the normal and cryptorchid dogs. Expression levels of UCN and CRHR2 mRNA were higher in cryptic epididymal ducts than that in normal epididymal ducts. These results suggest that UCN and its receptors might play a role in regulating the maturation and storage of spermatozoa. These findings indicated that the expression of these proteins could be modulated by the cryptorchidism condition.

Immunohistochemical localization of glucose transporter 1 and 3 in the scrotal and abdominal testes of a dog

Glucose is essential for testicular function; the uptake of carbohydrate-derived glucose by cells is mediated by glucose transporters (GLUTs). In the present study, we investigated the activity of GLUT1 and GLUT3, the two main isoforms of GLUTs found in testes, in the left scrotal and right abdominal testes of a German Shepherd dog. Immunohistochemical analysis showed that GLUT1 immunoreactivity was absent in the scrotal and abdominal testes. In contrast, weak to moderate GLUT3 immunoreactivity was observed in mature spermatocytes as well as spermatids in the scrotal testis. In the abdominal testis, relatively strong GLUT3 immunoreactivity was detected in Leydig cells only and was absent in mature spermatocytes and spermatids. GLUT3 immunoreactivity was significantly decreased in the tubular region of abdominal testis and significantly increased in the extra-tubular (interstitial) region of abdominal testis compared to observations in the each region of scrotal testis, respectively. These results suggest that GLUT3 is the major glucose transporter in the testes and that abdominal testes may increase the uptake of glucose into interstitial areas, leading to an increased risk of developing cancer.

MiRNA-133b promotes the proliferation of human Sertoli cells through targeting GLI3

Sertoli cells play critical roles in regulating spermatogenesis and they can be reprogrammed to the cells of other lineages, highlighting that they have significant applications in reproductive and regenerative medicine. The fate determinations of Sertoli cells are regulated precisely by epigenetic factors. However, the expression, roles, and targets of microRNA (miRNA) in human Sertoli cells remain unknown. Here we have for the first time revealed that 174 miRNAs were distinctly expressed in human Sertoli cells between Sertoli-cell-only syndrome (SCOS) patients and obstructive azoospermia (OA) patients with normal spermatogenesis using miRNA microarrays and real time PCR, suggesting that these miRNAs may be associated with the pathogenesis of SCOS. MiR-133b is upregulated in Sertoli cells of SCOS patients compared to OA patients. Proliferation assays with miRNA mimics and inhibitors showed that miR-133b enhanced the proliferation of human Sertoli cells. Moreover, we demonstrated that GLI3 was a direct target of miR-133b and the expression of Cyclin B1 and Cyclin D1 was enhanced by miR-133b mimics but decreased by its inhibitors. Gene silencing of GLI3 using RNA inference stimulated the growth of human Sertoli cells. Collectively, miR-133b promoted the proliferation of human Sertoli cells by targeting GLI3. This study thus sheds novel insights into epigenetic regulation of human Sertoli cells and the etiology of azoospermia and offers new targets for treating male infertility

Differential expression of estrogen receptor α and progesterone receptor in the normal and cryptorchid testis of a dog

Descending of the testes is an important process for spermatogenesis and cryptorchidism is one of the most relevant genital defects in dogs. In a previous study, we observed abnormal morphology and proliferation of Sertoli cells in a cryptorchid testis. In the present study, we investigated the expression of estrogen and progesterone receptors in the normal and cryptorchid testis of a dog. Elective orchidectomy was performed on the dog's abdominal right testis (undescended, cryptorchid) and scrotal left testis (descended, normal). In the normal testis, estrogen receptor α immunoreactivity was detected in Leydig cells alone, while estrogen receptor α immunoreactivity in the cryptorchid testis was significantly prominent in the Sertoli cells as well. In addition, progesterone receptor immunoreactivity in the control testis was detected in the spermatids, but was not detected in the cryptorchid testis. This result suggests that unilateral cryptorchidism causes increases of estrogen receptor α expression in Sertoli cells.