Spermatogenesis is a complex process regulated by endocrine and testicular paracrine/autocrine factors. Gonadotropins are involved in the regulation of several testicular paracrine factors, mainly of the IL-1 family and testicular hormones. Testicular cytokines and growth factors (such as IL-1, IL-6, TNF, IFN-gamma, LIF and SCF) were shown to affect both the germ cell proliferation and the Leydig and Sertoli cells functions and secretion. Cytokines and growth factors are produced by immune cells and in the interstitial and seminiferous tubular compartments by various testicular cells, including Sertoli, Leydig, peritubular cells, spermatogonia, differentiated spermatogonia and even spermatozoa. Corresponding cytokine and growth factor receptors were demonstrated on some of the testicular cells. These cytokines also control the secretion of the gonadotropins and testosterone in the testis. Under pathological conditions the levels of pro-inflammatory cytokines are increased and negatively affected spermatogenesis. Thus, the expression levels and the mechanisms involved in the regulation of testicular paracrine/autocrine factors should be considered in future therapeutic strategies for male infertility.
Animals ; Cytokines ; physiology ; Growth Substances ; physiology ; Homeostasis ; Humans ; Leydig Cells ; cytology ; Male ; Sertoli Cells ; cytology ; Spermatogenesis ; physiology ; Testis ; physiology

Plasminogen activator(PA) and plasminogen activator inhibitor(PAI) are involved in many physiological or pathological events. The Sertoli cells, the important elements within the seminiferous epithelium, are thought to play a key role in spermatogenesis. The Sertoli cells secrete PA and PAI. The levels of them are modulated by hormonal and cell-mediated influences. They play a fundamental role in the maintenance of spermatogenesis, sperm motility and fertilization.
Humans ; Male ; Plasminogen Activators ; metabolism ; physiology ; Plasminogen Inactivators ; metabolism ; physiology ; Sertoli Cells ; metabolism ; physiology ; Testis ; cytology

There has been no study aimed at directly determiningof the periods of Sertoli cell proliferation in birds evendomestic fowl. The aims of this study were to observe thecessation of post-hatching mitotic proliferation of Sertolicells in domestic fowl, and to determine the volumedensity of Sertoli and germ cells during this period. Atotal of 50 Leghorn chicks were used in this study. Thetestes sections of the animals were immunostained withBrdU to observe the proliferation of cells from one to 10weeks of age. The volume density of the Sertoli and germcells were determined using the standard point countingmethod. The volume density of the germ cell nuclei wasinitially less than that of the Sertoli cells but the volumedensity converged by week 6, and remained relativelyconstant until the commencement of meiosis. Clearlabeling of Sertoli and germ cells was observed from week1 to week 7. The only those cells still labeled after 8 weekswere germ cells, indicating that Sertoli cell proliferationhad ceased. Therefore, it is recommended that anyresearch into the testes of domestic fowl should considerthe cessation of Sertoli cell proliferation by approximately8 weeks.
Animals ; Bromodeoxyuridine/metabolism ; Cell Differentiation/physiology ; Cell Growth Processes/physiology ; Chickens/*physiology ; Histocytochemistry/veterinary ; Male ; Mitosis/physiology ; Sertoli Cells/*cytology/metabolism ; Spermatocytes/cytology ; Testis/*cytology/metabolism

Proto-oncogene, the fundamental component of cellular genome, is rarely or finitely expressed in normal conditions, and can regulate cellular proliferation, differentiation and information conduction. Many proto-oncogenes show the temporal and specific expression during spermatogenesis. The expression of some proto-oncogenes reinforces in the growth and development of Sertoli cells and Leydig cells. To explore the relationship between proto-oncogene and testicular function and that between proto-oncogene and regulative factors of testicular function helps to comprehend the regulation of the testicular function at the molecular level.
Animals ; Gene Expression Regulation, Developmental ; Humans ; Leydig Cells ; cytology ; Male ; Proto-Oncogenes ; physiology ; Sertoli Cells ; cytology ; Spermatogenesis ; genetics ; Testis ; physiology

Sptrx-1, 2 and 3 are a series of thioredoxins specifically expressed in the testis/sperm. They play a significant role structurally and functionally in the process of spermiogenesis. The genesis and mutation of sptrx-1, 2 and 3 are correlated to male reproduction. Taking sptrx-1, 2 and 3 as the target of study and treatment will open up a new field in the clinical study of male reproduction.
Humans ; Male ; Mutation ; Spermatogenesis ; genetics ; physiology ; Spermatozoa ; chemistry ; cytology ; metabolism ; Testis ; chemistry ; cytology ; metabolism ; Thioredoxins ; biosynthesis ; genetics ; physiology

Actin can be found in all kinds of eukaryotic cells, maintaining their shapes and motilities, while its dynamics in sperm cells is understood less than their nonmuscle somatic cell counterparts. Spermatogenesis is a complicated process, resulting in the production of mature sperm from primordial germ cell. Significant structural and biochemical changes take place in the seminiferous epithelium of the adult testis during spermatogenesis. It was proved that all mammalian sperm contain actin, and that F-actin may play an important role during spermatogenesis, especially in nuclear shaping. Recently a new model for sperm head elongation based on the acrosome-acroplaxome-manchette complex has been proposed. In Drosophila, F-actin assembly is supposed to be very crucial during individualization. In this mini-review, we provide an overview of the structure, function, and regulation characteristics of actin cytoskeleton, and a summary of the current status of research of actin-based structure and movement is also provided, with emphasis on the role of actins in sperm head shaping during spermiogenesis and the cell junction dynamics in the testis. Research of the Sertoli ectoplasmic specialization is in the spotlight, which is a testis-specific actin-based junction very important for the movement of germ cells across the epithelium. Study of the molecular architecture and the regulating mechanism of the Sertoli ectoplasmic specialization has become an intriguing field. All this may lead to a new strategy for male infertility and, at the same time, a novel idea may result in devising much safer contraception with high efficiency. It is hoped that the advances listed in this review would give developmental and morphological researchers a favorable investigating outline and could help to enlarge the view of new strategies and models for actin dynamics during spermatogenesis.
Acrosome ; physiology ; Actins ; chemistry ; physiology ; Animals ; In Vitro Techniques ; Intercellular Junctions ; physiology ; Male ; Sertoli Cells ; physiology ; ultrastructure ; Sperm Motility ; physiology ; Spermatogenesis ; physiology ; Testis ; cytology ; physiology

This article introduces the structure and function of the Sertoli cell cytoskeleton of the testis and the research progress in this aspect, focusing on the description of the function of vimentin, with some illustrations on the impact of physical and chemical factors on cytoskeleton, especially the structural changes of vimentin cell microfilament under simulated microgravity and space true microgravity. It for the first time proposes that the Sertoli cell cytoskeleton can be detected in semen, with a view to involving more researchers in further studies in this field.
Actin Cytoskeleton ; metabolism ; physiology ; Animals ; Apoptosis ; physiology ; Cytoskeleton ; metabolism ; physiology ; Humans ; Male ; Mice ; Rats ; Semen ; cytology ; metabolism ; Sertoli Cells ; cytology ; metabolism ; Testis ; cytology ; metabolism ; Vimentin ; metabolism

AIMTo isolate and transplant germ cells from adult mouse testes for transplantation.

METHODSIn order to distinguish transplanted cells from endogenous cells of recipients, donor transgenic mice expressing green fluorescent protein (GFP) were used. Germ cells were collected from the donors at 10-12 weeks of age and spermatogonia were concentrated by percoll fractionation and transplanted into recipient seminiferous tubules that had been previously treated with busulfan at 5 weeks of age to remove the endogenous spermatogenic cells.

RESULTSTwenty weeks after the transplantation, a wide spread GFP signal was observed in the recipient seminiferous tubules. The presence of spermatogenesis and spermatozoa was confirmed in sections of 12 out of 14 testes transplanted (86 %). However, when germ cells were transplanted without concentration the success rate was zero (0/9).

CONCLUSIONGerm cells from adult mouse testes can be successfully transplanted into recipient seminiferous tubules if the cell population is rich in spermatogonia and the percoll fractionation is useful in obtaining such a cell population.

Animals ; Cell Fractionation ; Green Fluorescent Proteins ; Luminescent Proteins ; genetics ; Male ; Mice ; Mice, Inbred C57BL ; Seminiferous Tubules ; cytology ; physiology ; Spermatogenesis ; physiology ; Spermatogonia ; physiology ; transplantation ; Testis ; cytology

We previously reported the successful establishment of embryonic stem cell (ESC)-like multipotent spermatogonial stem cells (mSSCs) from neonatal mouse testis. Here, we examined the ability of mSSCs to differentiate into vascular endothelial cells and smooth muscle cells, and compared to that of mouse ESCs. We used real-time reverse transcriptase polymerase chain reaction and immunohistochemistry to examine gene expression profiles of mSSCs and ESCs during in vitro vascular differentiation. Both mSSCs and ESCs exhibited substantial increase in the expression of mesodermal markers, such as Brachyury, Flk1, Mesp1, Nkx2.5, and Islet1, and a decrease in the expression of pluripotency markers, such as Oct3/4 and Nanog during the early stage of differentiation. The mRNA levels of vascular endothelial (VE)-cadherin and CD31 gradually increased in both differentiated mSSCs and ESCs. VE-cadherin- or CD31-positive cells formed sprouting branch-like structures, as observed during embryonic vascular development. At the same time, vascular smooth muscle cell-specific markers, such as myocardin and alpha-smooth muscle actin (SMA), were also highly expressed in differentiated mSSCs and ESCs. Immunocytochemical analysis revealed that the differentiated cells expressed both alpha-SMA and SM22-alpha proteins, and exhibited the intracellular fibril structure typical of smooth muscle cells. Overall, our findings showed that mSSCs have similar vascular differentiation abilities to those of ESCs, suggesting that mSSCs may be an alternative source of autologous pluripotent stem cells for vascular regeneration.
Animals ; Animals, Newborn ; Biological Markers/metabolism ; Cell Differentiation/physiology ; Embryonic Stem Cells/cytology/physiology ; Endothelial Cells/*cytology/physiology ; Gene Expression ; Gene Expression Profiling ; Humans ; Immunohistochemistry ; Male ; Mice ; Muscle, Smooth, Vascular/*cytology/physiology ; Myocytes, Smooth Muscle/*cytology/physiology ; Pluripotent Stem Cells/*cytology/physiology ; Real-Time Polymerase Chain Reaction ; Spermatogonia/*cytology/physiology ; Testis/*cytology/physiology

OBJECTIVETo explore the methods of isolation, cultivation, purification, identification of the fetal mice testis Leydig cell and to observe its biological characteristics in vitro.

METHODSLeydig cells were isolated by 0.03% collagenase (type I) from fetal mice testis and cultured in DMEM/F12 medium. The identity and purity of Leydig cell were assessed by 3beta-hydroxysteroid dehydrogenase delta4-delta5 isomerase (3beta-HSD). Cell viability was measured by trypan blue. Testosterone level in the medium of cultured Leydig cells was measured in various culture phases and cell density by radioimmunoassay.

RESULTSThe purity of Leydig cell was (45.10 +/- 1.66)% before culture, and (81.17 +/- 2. 32)% 72 h after culture. The level of testosterone secreted by Leydig cells could be detected in the medium and its level was associated with the density and time of cultured Leydig cells. The secretion capacity of testosterone by single Leydig cell decreased gradually during the culturing period.

CONCLUSIONThe fetal Leydig cells isolated from fetal mice testis have high purity. It can be cultured and kept the secretion ability of testosterone for a few days in vitro. This system can provide a valuable model for further study on the cellular function of the Leydig cells of fetal mice.

Animals ; Cell Separation ; Cells, Cultured ; Leydig Cells ; cytology ; physiology ; Male ; Mice ; Mice, Inbred Strains ; Testis ; embryology ; Testosterone ; secretion