Loss Of Spermatogonia Research Articles

Cellular Modifications in Spermatogenesis during Seasonal Testicular Regression: An Update Review in Mammals.

Simple SummaryThe most common form of reproduction in mammals is seasonal reproduction. This ensures that offspring are born at the most suitable time for survival, due to the abundance of food and the optimal temperatures for early postnatal development. In males, one way to achieve this is to decrease or lose fertility over a given period. This loss is associated with a greater or lesser degree of spermatogenesis modification that affects both germ and Sertoli cells. This paper reviews the different cellular mechanisms that have been postulated in recent years to explain how the activity of the seminiferous epithelium decreases during the non-reproductive period.Testicular regression occurs during the non-breeding season in many mammals. This affects spermatogenesis, resulting in decreased or arrested activity. Both lead to a decrease or cessation in sperm production. In recent years, the cellular mechanisms that lead to infertility in males in non-reproductive periods have been studied in very different species of mammals. At the start of the present century, the main mechanism involved was considered as an increase in the apoptotic activity of germ cells during the regression period. The loss of spermatogonia and spermatocytes causes not only a decrease in spermatogenesis, but an arrest of the seminiferous epithelium activity at the end of regression. Recently, in some mammal species, it was found that apoptosis is the usual mechanism involved in epithelium activity arrest, although it is firstly atrophied by massive desquamation of the germ cells that are released from their binding with the Sertoli cells, and which are shed into the lumen of the seminiferous tubule. In other species, it has been shown that not only germ cell apoptosis, but also Sertoli cell apoptosis, including decreased proliferative activity, spermatophagy or autophagy, are involved in testicular regression. Furthermore, the most recent studies indicate that there are multiple patterns of seminiferous epithelium regression in seasonally breeding animals, which may not only be used by different species, but also by the same ones to reproduce in the best conditions, ensuring their survival. In conclusion, at this time, it is not possible to consider the existence of a paradigmatic cellular mechanism in the involution of the seminiferous epithelium applicable to all male mammals with seasonal reproduction, rather the existence of several mechanisms which participate to a greater or lesser extent in each of the species that have been studied to date.

Dietary fluted pumpkin seeds induce reversible oligospermia and androgen insufficiency in adult rats

ABSTRACTSome components of the human diets are believed to be promising male contraceptive agents. The present study examined the antispermatogenic efficacy, reversibility and toxicity of fluted pumpkin seed-supplemented diet (DFPS) in adult male Wistar rats. Adult rats were given DFPS at 2.5, 5 and 10% for 60 days followed by 60 days post-treatment period. The control animals received normal standard rat diet not supplemented with fluted pumpkin seeds. The sperm quality variables, testosterone and follicle-stimulating hormone (FSH), oxidative status of the testis, steroidogenic enzymes and gamma-glutamyl transferase (γ-GT) activities and the histology of the testis were determined to evaluate the anti-fertility activity of fluted pumpkin seeds. Treatment of animals with DFPS at 5% and 10% resulted in decreased serum and intra-testicular testosterone and FSH concentrations. This effect was associated with decreased activity of 17β-hydroxysteroid dehydrogenase (17β-HSD), increased testicular oxidative stress and poor sperm quality in the 10% diet group. After 60 days DFPS post-treatment, intra-testicular 17β-HSD and γ-GT activities, FSH and testosterone levels recovered to control values. Furthermore, poor sperm motility, count, morphology and viability as well as severe loss of spermatogonia and other matured epithelial germ cells and Sertoli cells observed especially in the 10% DFPS-treated animals reverted to nearly control values 60 days after withdrawal of treatment. Dietary fluted pumpkin seeds may selectively act on the epithelial germ cells, possibly mediated via Sertoli cells, leading to oligospermia, oxidative damage and androgen insufficiency. The reversibility of these effects to near normal levels after withdrawal of treatment justifies further consideration of DFPS as it may be an effective and readily reversible agent that meets the required criteria of a male contraceptive agent.Abbreviations: GC-MS: gas-chromatography mass spectrophotometry; MPO: myeloperoxidase; NO: nitric oxide; DFPS: dietary fluted pumpkin seeds; DFPS (REV): DFPS post-treatment; MDA: malondialdehyde; SOD: superoxide dismutase; CAT: catalase; GSH: glutathione; 3β-HSD: 3β-hydroxysteroid dehydrogenase; 17β-HSD: 17β-hydroxysteroid dehydrogenase; NAD: nicotinamide adenine dinucleotide (oxidized); NADH: nicotinamide adenine dinucleotide (reduced); ITT: intra-testicular testosterone; FSH: follicle-stimulating hormone; FPS: fluted pumpkin seeds; NIST: National Institute Standard and Technology; Av: absolute volume; Ac: cross-sectional area; ST: seminiferous tubules; γ-GT: gamma glutamyl transferase.

Transplantation of Spermatogonial Stem Cells Suspension into Rete Testis of Azoospermia Mouse Model.

The loss of spermatogonia following chemo-or radiotherapy leading to temporary or permanent infertility of the patient is a well known and unwanted side effect of many oncological therapies. In this study, germ cells were isolated from 4 days old mouse testis cells. Busulfan treatment was used to the eliminate proliferating cells in the testis of recipient mice. The donor cells suspended in DMEM, were introduced into the rete testis of recipient mice via microinjection method. To distinguish the progeny of the transplanted donor stem cells from endogenous germ cells, BrdU-labeled cells were used. In addition, real time PCR was performed to determine expression levels of ngn3 and LIN28 (spermatogonia stem cells markers)before and after transplantation. Western blot analysis was further performed to detect an increase in - ngn3 expression after transplantation. Transplantations of stem cells into rete testis of the recipients was done. Our results clearly showed a significant increase in spermatozoa number in epididymal luman Spermatogonial stem cells (SSCs) did not show alkaline phosphatase activities while ngn3 and LIN28 were clearly expressed. Ngn3 and LIN28 expression were reduced after busulfan treatment compared to untreatmented mice. However, the expression of ngn3 and LIN28 increased after transplantation . BrdU-labeled testis cells were successfully transplanted into rete testis of recipient mice. These cells remained in rete testis of all recipient mice up to two months after transplantation. The present study clearly confirme that a regeneration after cytotoxic treatment was based on morphological criteria. We demonstrated the increase in stem cell numbers during regeneration and after transplantation. Transplantation of spermatogonial stem cells suspension by the injection of cells via the rete testis of recipient azoospermia model considerably enhances the efficiency of this procedure.

1375 FUNCTIONAL ANALYSIS OF SPERMATOGONIAL STEM CELLS IN CRYPTORCHIDISM USING EEF1A1 AND TPT1 GENE EXPRESSION AS INDEXES OF CELL DIFFERENTIATION

You have accessJournal of UrologyPediatrics: Andrology - Cryptorchidism & Varicoceles1 Apr 20121375 FUNCTIONAL ANALYSIS OF SPERMATOGONIAL STEM CELLS IN CRYPTORCHIDISM USING EEF1A1 AND TPT1 GENE EXPRESSION AS INDEXES OF CELL DIFFERENTIATION Kentaro Mizuno, Yoshiyuki Kojima, Hideyuki Kamisawa, Satoshi Kurokawa, Makoto Imura, Yoshinobu Moritoki, Hidenori Nishio, Yasuhiro Shibata, Akihiro Nakane, Toshiki Kato, Tetsuji Maruyama, Yutaro Hayashi, and Kenjiro Kohri Kentaro MizunoKentaro Mizuno Nagoya, Japan More articles by this author , Yoshiyuki KojimaYoshiyuki Kojima Nagoya, Japan More articles by this author , Hideyuki KamisawaHideyuki Kamisawa Nagoya, Japan More articles by this author , Satoshi KurokawaSatoshi Kurokawa Nagoya, Japan More articles by this author , Makoto ImuraMakoto Imura Nagoya, Japan More articles by this author , Yoshinobu MoritokiYoshinobu Moritoki Nagoya, Japan More articles by this author , Hidenori NishioHidenori Nishio Nagoya, Japan More articles by this author , Yasuhiro ShibataYasuhiro Shibata Nagoya, Japan More articles by this author , Akihiro NakaneAkihiro Nakane Nagoya, Japan More articles by this author , Toshiki KatoToshiki Kato Nagoya, Japan More articles by this author , Tetsuji MaruyamaTetsuji Maruyama Nagoya, Japan More articles by this author , Yutaro HayashiYutaro Hayashi Nagoya, Japan More articles by this author , and Kenjiro KohriKenjiro Kohri Nagoya, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.1759AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES It has been suggested that future fertility is affected by the number or function of spermatogonia derived from spermatogonial stem cells in cryptorchid testes. We have previously found that EEF1A1 and TPT1 genes are differentially expressed in human cryptorchid testes and believe that these genes reflect the stage of spermatogonia development. In this context, we have previously evaluated the expression of these genes in boys aged 1–5 years, but expression in other age groups remains unclear. To elucidate the chronological differentiation in spermatogonia, we assessed cryptorchid testes by histological and molecular biological examination. METHODS We used specimens derived from testicular biopsy during orchiopexy for cryptorchidism (88 cases, 109 testes) from October 2001 to April 2011. The patients were divided into 2 groups:(1) early orchiopexy (before 1 year of age) and (2) late orchiopexy (after 6 years of age). Histological assessment using light microscopy and molecular biological assessment using the expression levels of EEF1A1 and TPT1 genes by real-time RT-PCR were performed. Relative expression values of these genes were calculated and compared with those from age-matched descended testes. RESULTS The number of spermatogonia per tubule was significantly higher in the early orchiopexy group (p < 0.005). Relative expression values of the EEF1A1 gene were not significantly different between groups, whereas those of the TPT1 gene in the late orchiopexy group were significantly lower than those of age-matched descended testes (p < 0.005). CONCLUSIONS It has been suggested that leaving cryptorchid testes until school age induces testicular fibrillization and loss of spermatogonia. Combined with our previous results, it can be seen that the EEF1A1 gene is highly expressed until 6 years of age and is subsequently equally expressed in cryptorchid testes and descended testes. In contrast, expression of the TPT1 gene was lower in cryptorchid testes than descended testes after 6 years of age. The TPT1 gene was expressed in spermatogonia and was associated with an undifferentiated state of these cells, suggesting that spermatogonia could not maintain stemness in cryptorchid testes. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e558-e559 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kentaro Mizuno Nagoya, Japan More articles by this author Yoshiyuki Kojima Nagoya, Japan More articles by this author Hideyuki Kamisawa Nagoya, Japan More articles by this author Satoshi Kurokawa Nagoya, Japan More articles by this author Makoto Imura Nagoya, Japan More articles by this author Yoshinobu Moritoki Nagoya, Japan More articles by this author Hidenori Nishio Nagoya, Japan More articles by this author Yasuhiro Shibata Nagoya, Japan More articles by this author Akihiro Nakane Nagoya, Japan More articles by this author Toshiki Kato Nagoya, Japan More articles by this author Tetsuji Maruyama Nagoya, Japan More articles by this author Yutaro Hayashi Nagoya, Japan More articles by this author Kenjiro Kohri Nagoya, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Deleterious effects of cypermethrin on semen characteristics and testes of dwarf goats ( Capra hircus)

This study was carried out on 30 male dwarf goats to determine the effects of cypermethrin (CY) on semen characteristics and at tissue level in testes. Animals were divided randomly into five equal groups and each group was dipped with 0%, 0.1%, 0.4%, 0.8% or 1.6% CY, on days 0 and 15. The semen was collected at day 0, then fortnightly till 75 days and evaluated for physical characteristics, sperm morphology and concentration. None of the parameters studied showed any statistical difference on days 0 and 15 of sample collection. From day 30, effect of CY on semen characteristics started to appear and was more pronounced from days 45 to 75. Significantly ( P<0.01) decreased ejaculatory volume, motility percentage, mass activity, and concentration of spermatozoa were observed in treated groups as compared to control. With the treatment of CY, pH of semen became more alkaline. Semen color changed from creamy (control) to milky white to straw color in treated bucks. Percentage of abnormal spermatozoa (tailless, bent tails, coiled tailed) was much higher in treated animals than in control. Dead spermatozoa increased significantly ( P<0.01) in the treatment groups from days 30 to 75 as compared to the control group. All these changes were dose dependent, being less with low CY dose and more even extensive with high CY dose. Slight to moderate improvement in the above parameters was observed at day 75 nearly in all treated groups. Grossly decreased weight of testis and cyanotic epididymides were observed in bucks treated with 1.6% CY. Histopathologically, degenerative changes and loss of spermatogonia, spermatocyte, Sertoli cells, spermatids, and spermatozoa in seminiferous tubules were also dose dependent. It was concluded that CY caused dose-dependent effects on all parameters studied. High doses of CY (0.8% and 1.6% solution) affected the parameters on semen characteristics, though this effect seems to be transient as improvement in these parameters was observed at day 75; however, CY in goats should be used with great care to avoid over-dosage.

Ataxia with loss of Purkinje cells in a mouse model for Refsum disease

Refsum disease is caused by a deficiency of phytanoyl-CoA hydroxylase (PHYH), the first enzyme of the peroxisomal alpha-oxidation system, resulting in the accumulation of the branched-chain fatty acid phytanic acid. The main clinical symptoms are polyneuropathy, cerebellar ataxia, and retinitis pigmentosa. To study the pathogenesis of Refsum disease, we generated and characterized a Phyh knockout mouse. We studied the pathological effects of phytanic acid accumulation in Phyh(-/-) mice fed a diet supplemented with phytol, the precursor of phytanic acid. Phytanic acid accumulation caused a reduction in body weight, hepatic steatosis, and testicular atrophy with loss of spermatogonia. Phenotype assessment using the SHIRPA protocol and subsequent automated gait analysis using the CatWalk system revealed unsteady gait with strongly reduced paw print area for both fore- and hindpaws and reduced base of support for the hindpaws. Histochemical analyses in the CNS showed astrocytosis and up-regulation of calcium-binding proteins. In addition, a loss of Purkinje cells in the cerebellum was observed. No demyelination was present in the CNS. Motor nerve conduction velocity measurements revealed a peripheral neuropathy. Our results show that, in the mouse, high phytanic acid levels cause a peripheral neuropathy and ataxia with loss of Purkinje cells. These findings provide important insights in the pathophysiology of Refsum disease.

Loss of spermatogonia and wide-spread DNA methylation defects in newborn male mice deficient in DNMT3L

BackgroundFormation of haploid spermatozoa capable of fertilization requires proper programming of epigenetic information. Exactly how DNMT3L (DNA methyltransferase 3-Like), a postulated regulator of DNA methyltransferase activity, contributes to DNA methylation pattern acquisition during gametogenesis remains unclear. Here we report on the role of DNMT3L in male germ cell development.ResultsA developmental study covering the first 12 days following birth was conducted on a Dnmt3L mutant mouse model; lower germ cell numbers and delayed entry into meiosis were observed in Dnmt3L-/- males, pointing to a mitotic defect. A temporal expression study showed that expression of Dnmt3L is highest in prenatal gonocytes but is also detected and developmentally regulated during spermatogenesis. Using a restriction enzyme qPCR assay (qAMP), DNA methylation analyses were conducted on postnatal primitive type A spermatogonia lacking DNMT3L. Methylation levels along 61 sites across chromosomes 4 and X decreased significantly by approximately 50% compared to the levels observed in Dnmt3L+/+ germ cells, suggesting that many loci throughout the genome are marked for methylation by DNMT3L. More so, hypomethylation was more pronounced in regions of lower GC content than in regions of higher GC content.ConclusionTaken together, these data suggest that DNMT3L plays a more global role in genomic methylation patterning than previously believed.

Germ cell transplantation as a tool for fertility preservation of oncological patients

Spermatogonia are the diploid cells in the testis, representing a small self-sustaining pool of male germ line stem cells as well as a larger pool of differentiating germ cells which enter the process of spermatogenesis. After going through prophase of meiosis as spermatocytes these cells finally leave the testis as sperm. Spermatogonia share many characteristics with other stem cells but also carry some specific physiological features. Many details about the kinetics of spermatogonial divisions, about the hormonal regulation of their expansion and differentiation and about their clinically relevant involvement as a cause for male infertility are poorly understood. However, the loss of spermatogonia following chemo- or radiotherapy leading to temporary or permanent infertility of the patient is a well known and unwanted site effect of many oncological therapies. Isolation and extracorporal storage of spermatogonia prior to the treatment and transplantation into the testis after recovery from the disease presents a promising future tool for fertility preservation in male patients undergoing oncological therapy.

Germ cell-Sertoli cell interactions: regulation by germ cells of the stage-specific expression of CP-2/cathepsin L mRNA by Sertoli cells.

CP-2/cathepsin L mRNA is expressed primarily by rat Sertoli cells within stage VI-VIII seminiferous tubules. To test whether germ cells regulated this expression, we examined if separating Sertoli cells from specific germ cells affected expression of this transcript in Sertoli cells. First, Sertoli cells were isolated from adult (90-day-old) and immature (25-day-old) rats and levels of this transcript measured immediately or after 1, 3 and 5 days in culture. Results demonstrated that immediately upon isolation, CP-2/cathepsin L mRNA levels were significantly higher in mature cells. However, after 1 day in culture, the levels of this transcript increased in immature cells and remained high in mature cells. We therefore conclude that in vivo, a subset of germ cells inhibit the expression of CP-2/cathepsin L mRNA by immature Sertoli cells. Second, to examine the effect of specific germ cells on CP-2/cathepsin L mRNA expression, we exposed the testes of mature rats to 3 Gy of gamma-radiation and analyzed stage-specific expression of this transcript at varying times during maturation depletion and subsequent germ cell restoration. Loss of spermatogonia or spermatocytes was without effect. However, when pachytene spermatocytes through step 14 spermatids were depleted, expression at stages VI-VIII was reduced by half and expression at stages IX-I was increased 14-fold. These changes resulted in the loss of stage-specific expression of CP-2/cathepsin L mRNA by Sertoli cells. Finally, stage VI-VIII tubules, depleted primarily in step 15-19 spermatids, had levels of CP-2/cathepsin L mRNA that were 60% of control. However, stage-specific expression of this transcript was detected in these tubules. In contrast to what we noted with CP-2/cathepsin L mRNA, loss and restoration of germ cells had no effect on Sertoli cell levels of SGP-2 mRNA, indicating that testicular irradiation had no overall effect on Sertoli cell function. Taken together, these data suggest that the stage-specific expression of the CP-2/cathepsin L gene results from the sequential stimulation and inhibition of Sertoli cells by germ cells, that pachytene spermatocytes through step 14 spermatids are required for this stage-specific expression and that step 18 and 19 spermatids amplify this expression at stages VI-VIII.

Germ cell control of testin production is inverse to that of other Sertoli cell products.

Recent studies have shown that germ cells can regulate testins, two newly identified Sertoli cell proteins that are associated with junctional complexes. To investigate this possibility, several parameters of Sertoli cell function were investigated over 2-120 days post exposure of the rat testes to x-rays (3 Grays). The irradiation-induced loss of spermatogonia resulted in a maturation-depletion process progressively affecting all germ cell classes. Testis weight began to decrease when the most numerous germ cell type (spermatids) began to decline. A complete or near complete recovery of spermatogenesis and of the testis weight had occurred by day 120 post irradiation. There was no significant change in FSH, epididymal androgen-binding protein, and tubule fluid levels during the first weeks after irradiation, when the seminiferious epithelium was depleted of spermatogonia and germ cells up to early spermatids. In contrast, when the number of the more mature forms of spermatids declined (between day 21 and 54), FSH rose and androgen-binding protein as well as fluid production declined. The subsequent recovery of these parameters was also highly correlated with the number of late spermatids. By contrast, testicular testin contents reacted to the depletion of germ cells with a biphasic increase; a doubling occurred when spermatogonia, spermatocytes, and early spermatids were absent (days 4-28), and a 7-fold rise occurred by day 37 when the number of late spermatids had decreased by 50%. By day 54, when the sperm counts had reached a nadir, testin contents had returned to levels corresponding to about four times the control levels; they progressively recovered thereafter. These observations support the postulate that germ cells negatively regulate testins. This possibility was investigated with in vitro experiments showing that addition of germ cell-conditioned medium to Sertoli cell monolayers inhibited testin secretion in a dose-dependent manner. In conclusion this study; 1) highlights the complex interplay between the various germ cell classes in the control of the Sertoli cell function in the adult testis; 2) establishes that germ cell effects may be opposite on different Sertoli cell products; 3) demonstrates that several classes of germ cells negatively control testicular testin contents; and 4) emphasizes the particular role of late spermatids in Sertoli cell regulation.

Comparative study of spermatogonial survival after x-ray exposure, high LET (HZE) irradiation or spaceflight.

Spermatogonial cell loss has been observed in rats flown on Space Lab 3, Cosmos 1887, Cosmos 2044 and in mice following irradiation with X-ray or with high energy (HZE) particle beams. Spermatogonial loss is determined by cell counting in maturation stage 6 seminiferous [correction of seminferous] tubules. With the exception of Iron, laboratory irradiation experiments (with mice) revealed a similar pattern of spermatogonial loss proportional to the radiation dose at levels less than 0.1 Gy. Helium and Argon irradiation resulted in a 5% loss of spermatogonia after only 0.01 Gy exposure. However, significant spermatogonial loss (45%) occured at this radiation level with Iron particle beams. The loss of spermatogonia during each space flight was less than 10% when compared to control (non-flight) animals. This loss, although small, was significant. Although radiation may be a contributing factor in the loss of spermatogonia during space flight, exposure levels, as determined by dosimetry, were not significant to account for the total cell loss observed.

Timing of therapy of cryptorchidism

Dysfunctions of the endocrine glands are among the most prominent causes of cryptorchidism. Whereas all gonads show spermatogonia during the first to sixth months of life, loss of spermatogonia is seen in 25% of children with unilateral cryptorchidism already in the second year of life. A randomised study revealed decreased in gonadotropin reserves which was more marked after unsuccessful treatment than after successful therapy. In 119 treated children, the quota of descended testicles was between 47 and 55%. Ultrastructurally, LH-RH exercises an action on Leydig's cells. Treatment should be initiated already in the first year of life. LH-RH is recommended as the first conservative treatment. If this is not successful, additional administration of chorionic gonadotropin (HCG) can achieve descent in an additionally high percentage of cases.