Recent studies show that long exposure to high altitude and hypoxia can seriously affect men's reproductive health by reducing their sperm concentration, which decreases with the increase of altitude. High altitude and hypoxia are strongly associated with spermatogenic reduction, sperm DNA damage, sperm apoptosis, and decreased level of sex hormones. This article reviews the mechanisms of high altitude and hypoxia affecting sperm concentration.
Altitude ; Humans ; Hypoxia ; Male ; Sperm Count ; Spermatogenesis ; Spermatozoa ; physiology

Inhibin B is a glycoprotein secreted by testis, consisting of two disulfide-linked subunits, an alpha-subunit and a beta B-subunit. Serum inhibin B levels are significantly negatively correlated with the serum FSH levels in males, exerting a negative feedback on FSH secretion. In males the circulating levels of inhibin B increase shortly after birth and peak at 4-12 months of age, then decrease to low levels from 3-9 year. From the onset of puberty, the levels of inhibin B gradually increase. By pubertal stage II, the adult levels of inhibin B have been reached. At stage III of puberty, a negative correlation between inhibin B and FSH levels is present and persists from stage III of puberty onward. At 20-30 year of age, the levels of inhibin B reach another peak, then gradually decline with increasing age. The men with hypospermatogenesis and spermatogenesis arrest have significantly lower levels of inhibin B than those with normal spermatogenesis. The men with Sertoli-cell-only syndrome (SCO) have extremely low levels of inhibin B. There is a closely correlation between the presence of SCO and the level of serum inhibin B. A significantly positive correlation is also observed between testis volume and inhibin B level, as well as between sperm count and inhibin B level. The inhibin B is a direct product of the seminiferous tubules, reflecting the total testicular tissue. The measurable inhibin B production in adult requires the presence of germ cells. Inhibin B is regarded as a serum marker of spermatogenesis. The determination of serum inhibin B in males can be used to assess the spermatogenesis of infertile men, to diagnose the cryptorchidism and precocious puberty, to predict the outcome of testicular sperm extraction in men with non-obstructive azoospermia, and to evaluate the damage to spermatogenesis in men after radiotherapy or chemiotherapy.
Biomarkers ; blood ; Humans ; Inhibins ; blood ; Male ; Spermatogenesis ; physiology

Spermatogenesis, a continuous course of cell proliferation and differentiation, depends on reproductive hormones. FSH and LH-induced T are the main hormones regulating spermatogensis. Intratesticular T is one of the key factors in maintaining spermatogenesis, while FSH is just as important for origination and maintenance of normal spermatogenesis. Sertoli cells are the pivot of hormonal regulation. Interestingly, these reproductive hormones also regulate sperm cell apoptosis spermatogenesis. Further studies on the hormonal regulation of spermatogenesis provide a base for the development of safe and recoverable contraceptives for males.
Androgens ; physiology ; Apoptosis ; Contraception ; Follicle Stimulating Hormone ; physiology ; Humans ; Luteinizing Hormone ; physiology ; Male ; Spermatogenesis

Progesterone, as a female hormone, plays an important role in the physiological function and pregnancy maintenance in women. Recent studies show that progesterone and its receptor are also involved in male reproduction, and its receptor mRNA exists in male sexual glands. It is believed that progesterone, binding to its receptor, can regulate spermatogenesis and improve the fertilization of sperm, while the sperm from those with oligospermia, asthenozoospermia, teratospermia or unexplained infertility exhibit a low fertility due to the deficient expression of the progesterone receptor and insensitive reaction to progesterone. This review focuses on the progress in the studies of progesterone and its receptor in male reproduction.
Fertility ; Humans ; Male ; Progesterone ; physiology ; Receptors, Progesterone ; physiology ; Spermatogenesis ; Spermatozoa ; physiology ; Testis ; metabolism

Inhibin B, a dimeric glycoprotein, is directly secreted by the testis and responses to a diversity of exogenic hormones. Serum inhibin B levels will be influenced by different factors, such as age, testis volume, the time of puberty, the time of sample collection, varied groups of people and so on. Inhibin B is directly relevant to spermatogenesis of the testis and can be viewed as a valuable marker to assess male fertility. The determination of serum inhibin B has an applicable value in diagnosing the etiology of male infertility, assessing the damage to spermatogenesis in men after radiotherapy or chemiotherapy, and evaluating therapeutic effect on cryptorchidism and varicocele. Moreover, as far as assisted reproductive technology is concerned, the investigation of serum inhibin B has a predictive value in testicular sperm extraction.
Fertility ; physiology ; Humans ; Inhibins ; analysis ; physiology ; Male ; Reproductive Techniques, Assisted ; Spermatogenesis ; physiology

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

AIMTo study polyethylenimine (PEI)-mediated in vivo gene transfection into testis cells and preliminary functional research of spermatogenic cell-specific gene NYD-SP12 using this method.

METHODSPEI/DNA complexes were introduced into the seminiferous tubules of mouse testes using intratesticular injection. Transfection efficiency and speciality were analyzed on the third day of transfection with fluorescent microscopy and hematoxylin staining. The long-lasting expression of the GFP-NYD-SP12 fusion protein and its subcellular localization in spermatogenic cells at different stages were analyzed with fluorescent microscopy and propidium iodide staining.

RESULTSWith the mediation of PEI, the GFP-NYD-SP12 fusion gene was efficiently transferred and expressed in the germ cells (especially in primary spermatocytes). Transfection into Sertoli cells was not observed. The subcellular localization of the GFP-NYD-SP2 fusion protein showed dynamic shifts in spermatogenic cells at different stages during spermatogenesis.

CONCLUSIONPEI can efficiently mediate gene transfer into spermatocytes. Thus, it might be useful for the functional research of spermatogenic-cell specific genes such as the NYD-SP12 gene. In our study, the NYD-SP12 protein was visualized and was involved in the formation of acrosome during spermatogenesis. Our research will continue into the detailed function of NYD-SP12 in spermatocytes.

Animals ; Green Fluorescent Proteins ; Homeodomain Proteins ; genetics ; physiology ; Humans ; Male ; Mice ; Polyethyleneimine ; Spermatogenesis ; physiology ; Transfection ; methods

The two-dimensional model of cell culture is an important method in the study of testicular development and spermatogenesis but can not effectively mimic and regulate the testicular microenvironment and the whole process of spermatogenesis due to the lack of relevant cell factors and the disruption of a three-dimensional spatial structure. In the past 20 years, the development and optimization of the in vitro model such as testis organotypic culture and in vivo model such as testis transplantation achieved a transformation from two- to three-dimension. The maintenance and optimization of the testicular niche structure could mimic the testicular microenvironment and cell types including Leydig, Sertoli and germ cells, which showed similar biological behaviors to those in vivo. Besides, the cell suspension or tissue fragment floats in the gas-liquid interface so that the development of somatic and germ cells is well maintained in vitro whilst the feedback linkage between grafted testis tissue and hypothalamus-pituitary of the host rebuilt in the in vitro model provides an endocrinological basis for spermatogenesis, which serves as an effective methodology to better understand the organogenesis and development of the testis as well as testicular function regulation, advancing the concept of treatment of male infertility. Al- though each of the methods may have its limitations, the progress in the processing, freezing, thawing, and transplantation of cells and tissues will surely promote their clinical application and present their value in translational medicine.
Cell Culture Techniques ; Germ Cells ; physiology ; Humans ; Infertility, Male ; therapy ; Male ; Spermatogenesis ; physiology ; Testis ; growth & development

Ropporin has been identified as a spermatogenic cell-specific protein and may be involved in sperm maturation, motility, capacitation, hyperactivation and acrosome reaction. However, latest studies have shown that Ropporin is expressed weakly in normal non-testis tissues and highly in hematologic malignancies. Its highly conservative expression in mammalians demonstrates its importance to life. This paper updates the characterization, expression and its distribution, and biological function of Ropporin, and the advances in the clinical researches of the protein.
Animals ; Humans ; Male ; Membrane Proteins ; physiology ; Spermatogenesis ; rho GTP-Binding Proteins ; physiology

The review summarized the recent progress on macrophages of male reproductive tract and the action of macrophages on male reproductive physiology and pathology. The close correlation and effect between testicular macrophages and Leydig cells, Sertoli cells, germ cells, hypothalamic-pituitary-gonadal axis were introduced, respectively. At the same time, it pointed out the changes of macrophages' morphology and function in immune orchitis, and their regulation on the development of orchitis. So the complex immune regulation network in testes and testicular macrophages playing an important role on spermatogenesis and the stableness of spermatogenetic microenvironment in testes were further illuminated, which can provide theoretical basis for clinic therapy.
Genitalia, Male ; cytology ; immunology ; physiology ; Humans ; Macrophages ; cytology ; immunology ; Male ; Orchitis ; immunology ; pathology ; Spermatogenesis ; physiology