Search

The testis serves as the reproductive gland in male mammals, primarily tasked with the production of sperm and synthesis of androgens. A complex signaling network consisting of various cell types, including germ cells, Sertoli cells, and Leydig cells, supports the structure and maintains the function of the testis. Apart from the hypothalamic-pituitary-gonadal axis, various sex hormones and cytokines are also implicated in the regulation of testicular function. The fibroblast growth factor (FGF) represents a crucial class of active cytokines that stimulate cell proliferation, induce tissue differentiation, and govern organ development. This review summarizes the molecular mechanisms of FGF regulating testicular development and spermatogenesis and maintaining male fertility.

Nanos2, a member of the Nanos2 gene family, is a specific gene in male germ cells and encodes an evolutionarily conserved RNA binding protein expressed in male primordial germ cells (PGCs) during the embryonic period as well as in the spermatogonial stem cells (SSCs) of the testis. In the embryonic period, Nanos2 promotes the development of male PGCs and inhibits them from meiosis. In the process of spermatogenesis, Nanos2 suppresses the differentiation of SSCs in the testis and maintains the stability of the SSC pool. The knockout of Nanos2 may cause the disappearance of germ cells and sterility in male mice while its overexpression in the testis may lead to accumulation of SSCs in seminiferous tubules. Besides, Nanos2 is involved in the degradation of specific RNAs and possibly associated with some diseases of the male reproductive system. This review focuses on the recent progress in the studies of Nanos2 in the male reproductive system.

Objective: To investigate the effect of aerobic exercise on the spermatogenic function of male rats and screen out differentially expressed proteins related to spermatonesis-regulation by proteomic analysis., Methods: We randomly divided 24 SD male rats into groups A (non-exercise control), B (exercise), and C (weight-bearing exercise), those in the latter two groups made to swim for 60 minutes a day and those in group C bearing a load 3% of the body weight, both 6 times a week for 9 weeks. At 24 hours after the last exercise, we obtained the sperm count, measured the levels of such serum reproductive hormones as testosterone (T), luteotrophic hormone (LH), follicle-stimulating hormone (FSH), and gonadotrophin-releasing hormone (GnRH), and employed isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analysis of the testicular tissue., Results: Compared with group A, group C showed significant increases in sperm concentration (［2.12 ± 0.43］ vs ［3.54 ± 0.52］ ×10⁶/ml, P <0.01) and the levels of serum LH (［35.99 ± 2.90］ vs ［38.96 ± 1.34］ IU/L, P <0.01) and T (［19.99 ± 0.25］ vs ［21.36 ± 0.53］ nmol/L, P <0.01), but no statistically significant differences in GnRH (［623.95 ± 41.44］ vs ［641.82 ± 42.78］ ng/L, P >0.05) and FSH (［20.49 ± 2.44］ vs ［22.29 ± 2.31］ IU/L, P >0.05). No significant changes were observed in sperm concentration or reproductive hormone levels in group B as compared with A. Group B exhibited obviously more mature sperm and cell layers in the seminiferous epithelium than group A. A total of 47 differentially expressed proteins were identified, of which 37 were up-regulated and the other 10 down-regulated. In addition, another 5 significantly differentially expressed proteins closely related to reproductive function were identified, including up-regulated Anx A1, GPX3, Rimbp3, and Dpy19l2 and down-regulated CYP17. Enrichment analysis showed that the differentially expressed proteins were mainly involved in extracellular matrix-receptor interaction, protein digestion and absorption, and focal adhesion pathways., Conclusions: Proper-intensity exercise can improve the spermatogenic function of rats. Aerobic exercise promotes spermatogenesis mainly by up-regulating the expressions of the proteins related to the production and differentiation of spermatozoa.

Objective: To investigate the presence of interactions between DNAJB13 and HK1., Methods: The open reading frame of Dnajb13 gene was amplified from mouse testis cDNA by PCR. The PCR products were then inserted into pGEX-4T-1 vector after double digestion and identified by sequencing. The recombinant plasmids were transformated into competent DH5a cells, and the fusion protein was expressed with IPTG induction. SDS-PAGE Coomassie brilliant blue staining and Western blot analysis were used to detect the fusion protein expression. The protein precipitated by GST-DNAJB13 in GST pull down assay was detected by Western blotting., Results: The recombinant plasmid pGEX-4T-1-Dnajb13 was successfully constructed and verified. E.coli transformed with the recombinant plasmid expressed abundant fusion protein. GST pull down assay showed interactions between DNAJB13 and HK1., Conclusion: DNAJB13 interacts with HK1 in mouse testis and probably participates in spermatogenesis and the regulation of sperm motility.

The ubiquitin-proteasome system (UPS) is a proteasome system widely present in the human body, which is composed of ubiquitin (Ub), ubiquitin activating enzymes (E1), ubiquitin conjugating enzymes (E2), ubiquitin protein ligases (E3), 26S proteasome, and deubiquitinating enzymes (DUBs) and involved in cell cycle regulation, immune response, signal transduction, DNA repair as well as protein degradation. Sperm DNA is vulnerable to interference or damage in the progression of chromosome association and homologous recombination. Recent studies show that UPS participates in DNA repair in spermatogenesis by modulating DNA repair enzymes via ubiquitination, assisting in the identification of DNA damage sites, raising damage repair-related proteins, initiating the DNA repair pathway, maintaining chromosome stability, and ensuring the normal process of spermatogenesis.

RNA binding proteins (RBPs) regulate the function of cells by interacting with nascent transcripts and therefore are receiving increasing attention from researchers for their roles in tissue development and homeostasis. The polypyrimidine tract binding (PTB) protein family of RBPs are important posttranscriptional regulators of gene expression. Further investigations on the post-transcriptional regulation mechanisms and isoforms of PTB proteins in the spermatogenesis show that PTB protein 1 (Ptbp1) is a predominant isoform in mitotic cells (spermatogonia), while Ptbp2 predominates in meiotic spermatocytes and postmeiotic spermatids and binds to the specific 3' untranslated region (3' UTR) of the phosphoglycerate kinase 2 (Pgk-2) mRNA, which helps to stabilize Pgk-2 mRNA in male mouse germ cells. In case of Ptbp2 inactivation in the testis, the differentiation of germ cells arrests in the stage of round spermatids, with proliferation of multinucleated cells in the seminiferous tubule, increased apoptosis of spermatocytes, atrophy of seminiferous tubules, and lack of elongating spermatids, which consequently affects male fertility. This article presents an overview on the structure of the PTB protein and its role in regulating mammalian spermatogenesis.

Objective: To investigate whether chemokine like factor (CKLF)-like myelin and lymphocyte and related proteins for vesicle trafficking and membrane link (MARVEL) transmembrane domain-containing protein 2 (CMTM2) is involved in spermatogenesis in varicocele induced subfertility rats and to discuss the possible mechanisms., Methods: Forty male SD rats (body weight: 220-330 g, age: 6-7 weeks) were randomly divided into 4 groups: varicocele for 4 weeks, varicocele for 12 weeks, sham operation for 4 weeks and sham operation for 12 weeks, with 10 rats in each group. These rats were introduced by partially ligating left kidney veins for the experimental groups, and the sham surgery groups as controls were executed with exactly the same surgery as in the experimental groups except for the ligation. The rats in control and experimental groups for 4 and 12 weeks were killed after laparotomy at the end of 4 and 12 weeks, respectively, the left testes and epididymis were taken out for counting the sperm, observing the seminiferous tubule change and immunochemistry for CMTM2. The changes included sperm density and motility, the outer diameter and inner diameter change and the changes of epithelium and the CMTM2 expression in immunochemistry., Results: Compared with the control groups, the sperm density [(63.9±7.1)×10 6 /mL vs.(74.3±5.0)×10 6 /mL] and motility [(58.7%±7.9%) vs.(66.1%±4.3%)] were reduced slightly in group of varicoele for 4 weeks, respectively (t=1.432, 1.563; P=0.076, 0.059, respectively). Varicocele significantly caused a decrease in sperm concentration [(40.5±7.2) ×10 6 /mL vs.(71.1±4.5)×10 6 /mL] and motility [(35.2%±8.5%)vs. (63.4%±4.1%)] at 12 weeks, compared with the related sham groups (t=3.754, 3.933; P=0.004, 0.002, respectively). Additionally, testis CMTM2 exhibited the same disparity, that is, the CMTM2 protein expression in varicocele group was significantly reduced, with the ratio of sham group to varicocele group at the end of 12 weeks 2.3±0.4 (t=1.978; P=0.039). In the evaluation of seminiferous tubules diameter, the external [(198.2±10.2) μm vs. (255.8±12.7) μm, t=2.125, P=0.003] and epithelium diameter [(54.1±1.5) μm vs. (75.5±4.1) μm, t=2.246, P=0.021] were decreased compared with the sham-related groups and previous varicocele groups. In all the varicocele groups, all types of sperm motility decreased compared with the related sham-operated group (P<0.05)., Conclusion: This study suggests varicocele has a detrimental effect on CMTM2 levels and decreases spermatogonia cell number, seminiferous tubules diameter, and sperm indices. CMTM2 is associated with sperm changes in rats with varicocele, and further studies are needed to study the mechanism.

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.

The hepatocyte growth factor ( HGF) is a multifunctional growth factor, which produces multiple biological effects by binding to the c-Met acceptor. This article reviews the biological properties of HGF, particularly those correlated with male reproduction, including its abilities to promote testis embryonic development, spermatogenesis, and testosterone synthesis of Leydig cells. HGF may provide a new insight into the treatment of male hypogonadism and infertility.

Sulfogalactosylglycerolipid (SGG) is the main glycolipid in male mammalian germ cells, which is selectively and highly expressed in mammalian testes and helps form the lipid bilayer of cell membrane. In the process of spermatogenesis, SGG is involved in the meiosis of spermiocytes. Either deficiency or accumulation of SGG will lead to male infertility. SGG homeostasis in the testis is the premise of normal spermatogenesis. In the process of sperm-zona binding, SGG becomes a component of lipid raft and provides a platform for signal transduction. The SGG binding protein plays a role in sperm-egg recognition and membrane fusion. SGG has a great research value and application prospect in male reproduction.

Objective: To study the effects of zeranol on spermiogenesis function of mice and its possible mechanism., Methods: 40 healthy mature male mice were randomly divided into four groups: negative group and zeranol exposure groups (25, 50, 100 mg/kg). Male mice were respectively administered with zeranol at the doses of 25, 50, and 100 mg/kg for 35 days and killed. The weights of spermary, epididymis and spermatocyst were measured. The sperm counting, motility and the percent of abnormal sperms were observed. Pathological changes of testicle tissue were also observed., Results: In comparison with control group, the visceral coefficient of spermatocysts and sperm counting of zeranol exposure groups were all decreased ( P < 0.05). Sperm motility were significantly decreased in the median and high exposure groups (P < 0.05). Pathological alterations of testes were also observed. Seminiferous epithelium was reduced in exposure groups, loose and anomalistic organization. Sperm counts were also reduced in the lumina of seminiferous tubules with glair., Conclusion: Zeranol have toxicity effect on spermigenesis function of male mice.

The special process and special structure which bring organelle during the spermiogenesis of Japanese eel, Anguilla japonica were observed by scanning electron microscope and transmission electron microscope. The process which spermatoblast became sperm including four special stages, the early stage, the middle stage, the later stage and the spermic stage, then came into being a normal mature sperm. In the early stage, cell nucleus became long form gradually by the oval form. In one side of the cell nucleus, there was a big and special globoid structure dyeing lower, account for 1/3 of cell nucleus cubage. It contains a little of deep dyeing grain form and the lines form material, the outside is wrapped by plasmalemma separated with the cell nucleus, the outside of that structure and cell nucleus still lay a plasmalemma. The spermiogenesis of early stage did not form independent centriolar complex and mitochondria. In the middle stage, the cell nucleus presented a long form with the globoid structure on the top of the nucleus, and the down side had no globoid structure where the flagellum primordium appears. The globoid structure changed with the spermiogenesis. The inner part of the globoid differentiated a centriolar complex and mitochondria step by step. The lysosomes distributed in the medium segment of the cell nucleus obviously. In the late stage, the cell nucleus was similar with the shape of eyebrow or crescent. The centriolar complex released from the globoid structure, then became an independent structure. There were mitochondria which had not become the independent structure still in the globoid structure. Under the karyon, there was flagellum primordium where sent a rather long flagellum. The flagellum formed a typical "9+0" microtubular structure at that time. The spermatozoa in this phase has movable ability. In the spermic stage, the cell nucleus was round in shape. The centriolar complex was inside implantation fossa. Mitochondria were under karyon. And under the mitochondria was the central space of the sleeve. The flagellum formed a typical "9+2" microtubular structure at that time. The spermatozoa of Japanese eel, A. japonica became complete mature spermatozoa must pass through four phases for abnormality.

Spermatogenesis in Caenorhabditis elegans, mainly consisting of meiosis and spermiogenesis (or sperm activation), is a complicated cell differentiation process. The germ cells develop into matured motile spermatozoa after the expression of specific genes during meiosis and protein posttranslational modification during spermiogenesis. The spermatozoa compete with each other, communicate with and finally fertilize the oocytes such that new individuals are generated. A group of mutants related to spermatogenesis, sperm motility and fertilization are obtained through the sterile screen. Some specific genes in spermatogenesis and fertilization have been cloned and their functions have been studied. C. elegans is an attractive model to dissect the complexities of spermatogenesis and fertilization. The advances in the study of C. elegans may give insights to important targets for the study of male infertility and contraceptives in humans.

Sperm membrane proteins play a key role in spermatogenesis, sperm maturation and sperm-oocyte interaction. A deeper research would shed new light on the molecular mechanisms of spermatogenesis, sperm maturation and fertilization. In recent years, with the extensive application of a variety of current molecular biological methods and bioinformatics to reproductive medicine, some sperm membrane proteins found previously have been cloned and sequenced. Furthermore, new sperm membrane proteins, being found continuously, will make a solid foundation for the development of contraceptive vaccine as well as for the investigation into the mechanism of fertilization at levels of gene and protein. This article reviews the current progress in the researches on sperm membrane proteins.

Aim: To express SRG4, a novel mouse spermatogenesis gene in E.coli and purify its fusion protein., Methods: RT-PCR was used to amplify the 586 bp fragment that was located in SRG4 C-end and included a Sad1&#95;UNC like domain. The PCR products were cloned into pUCm-T vectors and sequenced. Then the cDNA fragment was subcloned into PQE-30, a prokaryotic expression vector with 6xHis tag. PQE-30-SRG4 was sequenced and transformed into E.coli M15. The expression of histidine-tagged fusion protein was induced by IPTG. The histidine-tagged fusion protein was identified by Western blot and purified by Ni-NTA Agarose., Results: The recombinant plasmid PQE-30-SRG4 was constructed successfully and was expressed in E.coli M15. The expression of the fusion protein reached the top at 4-5 h after it was induced by IPTG. The fusion protein SRG4 with 6xHis tag was confirmed by Western blot and was purified by Ni-NTA Agarose., Conclusion: The recombinant plasmid PQE-30-SRG4 can be expressed in E.coli M15. The purified fusion protein including a Sad1&#95;UNC like domain can be used for studying the biological function of SRG4 in spermatogenesis.

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.

The available information indicates that estrogen receptor(ER) play a physiological role in the regulation of spermatogenesis in vertebrates. However, the cellular distribution of ER in the testis is poorly understood in invertebrates. The aim of this study was to determine the presence and cellular distribution of ER in the spermatogenesis of termite (Reticulitermes aculabialis). Immunocytochemical analysis showed ER was present in the nucleus of the primary spermatocytes, and the expression of ER was relatively stronger in the primary spermatocytes of the swarming termites. Previous studies have demonstrated the procerebrum of the swarming male termites could strongly secrete FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone) which stimulated estrogen secreting. In conclusion, we demonstrated here for the first time that ER might be an important factor in the regulation of the spermatogenesis of termites, and play an important role for starting and maintaining the meiosis cell division of spermatocytes.

Objective: To evaluate the role of spermatic nerves in the regulation of spermatogenesis., Methods: Fifty-four mature SD male rats (350-375 g) were randomized into a sham operation group (SO) and three experiment groups, and the latter underwent bilateral surgical removal of the superior spermatic nerve (SSN) or/and the inferior spermatic nerve (ISN). The animals were killed 1 month and 2 months after the operation. HE stain was used to observe spermatogenesis. Transmission electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) were employed to detect apoptosis., Results: Impaired spermatogenesis was observed 2 months after the operation, with only Sertoli cells and a few spermatogonia remaining in the regressed tubules in all the treatment groups. The abnormal tubules in the SSN, ISN and SSN + ISN denervated testes accounted for (13.25 +/- 2.03)%, (11.0 +/- 4.36)% and (34.17 +/- 3.78)% respectively. Chromosome condensation and fragmentation in the germ cells were observed under the electron transmission microscope in all the denervated testes. TUNEL showed the spermatogonia and Leydig cells to be apoptotic in all the denervated testes and the incidence of the apoptotic cells in the SSN + ISN denervated testes was significantly higher than in the SSN or ISN denervated ones., Conclusion: Spermatic nerves play an important role in spermatogenesis.

Objective: To establish the testis transplantation model in rats and to study the mechanism of graft injury., Methods: The testis orthotopic transplantation model was established using three-cuff method. The animals were divided into 6 groups. Serum levels of testosterone (T), luteining hormone (LH) and follicle-stimulating hormone (FSH) were determined by radioimmunoassay (RIA). Morphology and ultrastructure were examined by light and electron microscopy. Expression of Glial cell line-derived neurotrophic factor (GDNF) mRNA was studied by reverse-transcription polymerase chain reaction (RT-PCR) technique., Result: On the 7th day postoperatively, the allotransplanted testes showed perivascular massive infiltration of lymphocytes and polymorphonuclear neutrophil (PMN) and reduced number of the sertoli cells under light microscopy. It also showed the broken blood-testis barrier, the atrophy of the sertoli cells and spermatogenic cells arranged in disorder under electron microscopy. The decline of serum T level and the increase of serum LH and FSH levels were similar to those found in bilateral castrates. The levels of GDNFmRNA expression were lower than those in normal controls. On 14th day postoperatively, the spermatogenesis of allotransplanted testes was still not recovered and the expression of GDNFmRNA declined further., Conclusion: The atrophy and reduced number of the sertoli cells and the breakage of the close connection probably are the main causes of dysfunction of spermatogenesis. The decline of GDNFmRNA expression is in accordance with the dysfunction of the sertoli cells and the spermatogenesis.

Objective: To study the changes of testicular spermatogenic function after kidney transplantation., Methods: Thirty male patients with uremia underwent kidney transplantation. Semen analyses were made and sperm ultrastructural changes were studied before and after the operation., Results: Sperm viability, motility and movement velocity were significantly higher in the postoperative group than in the preoperative group [(70.08 +/- 2.86 vs (36.04 +/- 8.01)], [(76.15 +/- 3.75)% vs (39.27 +/- 4.14)%], [(16.80 +/- 1.11) microm/s vs (8.43 +/- 2.01)] micro/s, respectively (P < 0.01). Sertoli cell, acrosome and mitochondria structures inclined to normal after kidney transplantation., Conclusion: Kidney transplantation can significantly improve spermatogenic function in patients with uremia.

Objective: To screen the stage-specific expression proteins during rats spermatogenesis, and to investigate the beta-actin expression and localization in the tissues of rat testicular., Methods: Highly enriched type A spermatogonia, pachytene spermatocytes and round spermatids were isolated by STAPUT method (sedimentation velocity at unit gravity, with 2% - 4% BSA gradient in DMEM/F12 medium) respectively to get the total proteins. The difference of protein expression between the three kinds of cells was analyzed by two-dimensional electrophoresis. Then the distribution of beta-actin in rat testicular tissues was investigated using specific anti-beta-actin antibodies by immunohistochemical method., Results: beta-actin was identified as a stage-specific expression protein by two-dimensional electrophoresis. beta-actin protein was more strongly expressed in type A spermatogonia and pachytene spermatocytes, but not in round spermatids. The immunohistochemical results showed that beta-actin was mainly located in the cytoplasm of type A spermatogonia and pachytene spermatocytes and in the nuclei of nearly mature spermatids., Conclusion: beta-actin protein is a stage-specific expressed protein and may play an important role in spermatogenesis.

It was said that 11% of all men showed their infertility. The genetic origins of male infertility may be classified into three main groups: chromosome abnormalities, microdeletions and gene mutations. Growing literature has shown that spermatogenesis failure or reproductive failure (pregnancy wastages) occurred in male carriers of chromosomal distortion/aberration. But the mechanisms remain largely unsolved. Synaptonemal complex (SC) of human spermatocytes from such carriers offers new information. This review aims to summarize recent development of SC analysis for male infertile diagnosis and sum up our results obtained recently. The relationship between male infertility/sterility and SC abnormity was discussed and reviewed as following five aspects. (1) The association of XY-bivalent and the rearranged autosomes interfere with or affect, by their contact, X chromosome normal functions. (2) Male infertility is related to the incomplete pairing in break regions of rearranged autosomes. (3) SC fragmentation, lateral elements (LEs) swelling and pairing disorder result in spermatogenic failure. (4) This heterosynapsis at early stage of meiosis in rearranged autosomes, results in unbalanced germs and pregnancy wastages. (5) Gene mutations of SC proteins result in male infertility.

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.

Objective: To establish an in vitro model for the development of mouse spermatogenic cells into sperm by using the immunodefective mouse as the incubator., Methods: Tissue grafting was performed using testis from 1-2 days old Kun-ming mice as donor tissue and immunodefective mice as recipients; the expression of TESK1 mRNA in grafts was determined by RT-PCR and the spermatogenesis further observed with histological analysis of grafts., Results: Molecular biological and histological analyses showed that grafts post-grafting not only expressed TESK1 mRNA as in normal mouse testis, but also exhibited similarities in the structure of seminiferous tubules and component of spermatogenic cells, including sperms., Conclusion: Spermatogenic cells heterotopically grafted in vitro could continuously grow and complete spermatogenesis and finally develop into sperm.

Objective: To evaluate the changes of the semen quality in uremia patients before renal transplantation., Methods: The semen of 24 patients with uremia and 12 normal volunteers was analyzed., Results: The semen volume, sperm motility, survival rate, density and morphological normality percentage were (2.5 +/- 0.4) ml, (13.4 +/- 3.9)%, (25.4 +/- 5.6)%, (20.6 +/- 4.5) x 10(6)/ml and (16.8 +/- 2.1)%, respectively, significantly lower than those of the normal group (P < 0.01)., Conclusion: Semen qualities were lowered significantly and spermatogenesis severely affected in patients with uremia.

Objective: To explore the effect of scrotum reconstruction with a skin flap on spermatogenesis., Methods: Two patients who underwent scrotum reconstruction with the skin flap were followed up for four years. Their sperm quality, sex function, sexual hormone, and testis biopsy were examined. To exclude the influential factors of testis and spermatic cord contusing, an experiment study was designed and performed in rabbits. The scrotal skin of the rabbits was stripped off and the scrotum was reconstructed with a hypogastric skin flap., Results: The clinical follow-up indicated that in the early postoperative period, the reconstruction did not impede spermatogenesis, but the arrest of spermatogenesis happened with time. The experimental results showed that the sperm count of the rabbits decreased obviously and the rabbits became sterile two months after scrotum reconstruction., Conclusion: The thick skin flap is not recommended for scrotum reconstruction.

Objective: To evaluate the role of superior spermatic nerve in the regulation of spermatogenesis., Methods: Mature SD rats (350-375 g) received bilateral surgical removal of the superior spermatic nerve(SSN). The animals were killed 1 and 2 months after operation and were studied in comparison with the SD rats of the sham operation group. H. E. staining was employed in observing spermatogenesis, and transmission electron microscopy and terminal deoxynuleotidyl tansferase-mediated dUTP nick end-labeling (TUNEL) were used to detect apoptosis., Results: No pathological changes were observed 1 month after operation. Two months after SSN denervation, spermatogenesis arrest was seen in the seminiferous tubules in which only Sertoli cells or Sertoli cells and a few spermatogonia remained. Chromosome condensation and breakage in germ cells were observed under transmission electron microscope in denervated testes. TUNEL showed that SSN denervation induced apoptosis of spermatogonia and Leydig cells significantly., Conclusion: The superior spermatic nerve seems to be involved in the regulation of spermatogenesis. Further study is worth doing to clarify the possible mechanism of action.

Spermatogonial transplantation (ST) is a novel technique which mechanism is similar to other transplantations. The donor testicular cells transferred into recipient testes by the microinjection can initiate spermatogenesis and produce sperm in the recipient testis. The homograft has got success. The xenograft in which (man, horse, bull or rat, can be the donor; immunodeficiency mouse can be the recipient) and cryopreserved germ cells can not clonize in the recipient testes. The reason may be immunoreaction. ST technique will be propitious to these fields, 1. to investigate fundamental aspects of spermatogenesis; 2. to regenerate spermatogenesis in infertile individuals; 3. to develop transgenic animals.

Transforming growth factor beta (TGF beta) superfamily can regulate the development of primordial germ cell (PGC) and gonocyte. TGF beta, bone morphogenetic protein (BMP), activin, inhibin, and anti-Müllerian hormone (AMH), all of which belong to the TGF beta superfamily, can play important roles in male germ cell development. Their downstream signaling molecules, Smads proteins are involved in the signal transduction pathway. In addition, TGF beta and AMH contribute to the apoptosis during development. Understanding this effect will help to elucidate the molecular mechanism of the early development of male reproductive system and the pathogenesis of testicular cancer.

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.

The centrosomal protein, Cenexin, is a molecular marker of mature centriole. To elucidate the variability and function of mature centriole in spermatogenesis, the high titer polyclonal antibody against rat cenexin was obtained by immunizing mice with recombinant cenexin which was made up in this study. The expression of cenexin in rat spermatogenesis was carried out by semi-quantitative RT-PCR, immunofluorescence and Western Blot. The results demonstrated that the level of Cenexin mRNA was higher in spermatogonia and spermatocytes, then decreased in following stages, while Cenexin protein was located on one centriole from spermatogonia to spermatids, showing mature centriole existed in these stages. Cenexin protein was localized to the basal body of the flagellum in elongated spermatids and the stained signal disappeared in the most of epidydimal sperms. These results suggested that the expression pattern of cenexin in rat spermatogenesis might be related to the initiation of the flagella formation.

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.

The CRES (cystatin-related epididymal spermatogenic) protein defines a new subgroup in the family 2 cystatins of the cystatin superfamily of cysteine protease inhibitors. However, unlike the ubiquitous expression of cystatin C, the Cres gene is preferentialy expressed in postmeiotic germ cells, the proximal caput epididymidis, and anterior pituitary gonadotrophs. Furthermore, CRES protein lacks two of the three consensus sites necessary for the cystatin inhibition of C1 cysteine proteases. Therefore, CRES may perform unique and tissue-specific functions in the reproductive and neuroendocrine systems. In the present review, we describe our studies on: 1. the Cres gene promoter and the transcriptional regulatory protein and their associated DNA binding sites that may be important for tissue-specific expression; and 2. the biochemical function of CRES protein. In brief, Northern blot, gel shift analyses, and transient transfection assays demonstrated that the C/EBP beta (CCAAT/enhancer binding protein) transcription factor is the predominant C/EBP family member expressed in the epididymis and gonadotroph cells and is necessary for high levels of Cres expression in these two tissues. In other studies, analyses of transgenic mice expressing a CAT reporter gene driven by 1.6 kb of Cres promoter revealed CAT mRNA and protein only in the germ cells. These studies suggest that the 1.6 kb of Cres 5' flanking sequence contains the required DNA elements for expression in the testis, but lacks the elements to correctly target expression of the reporter gene in the epididymis. Alternatively, repressor elements may be present. Finally, in vitro protease assays were performed to determine if CRES functions as a protease inhibitor. In contrast to cystain C, CRES did not inhibit the C1 cysteine protease papain but rather inhibited at nanomolar concentrations the serine protease PC2, a prohormone processing enzyme. Therefore, CRES is a new cross-class inhibitor that may regulate PC2 of PC2-like proteases and suggests a role for CRES in the regulation of prohormone and proprotein processing.

The morphological variation of nucleus during spermatogenesis in Macrobrachium nipponense and its status during the reproductive evolution of Caridean shrimp were investigated using transmission electron microscopy(TEM) technique. During the whole process of spermatogenesis, the nuclear morphology of spermatogenic cell varied from spherical or ellipsoidal to shallow-dish-like shape, and the nuclear membrane existed only in the rear part of mature sperm varied from intact to unintegrated one. The chromatin gradually varied from loosen to coacervative one, and then, developed differentially into two types of nucleus in the mature sperm, i.e., vesicular nucleus and filamental nucleus, which became an important characteristics of Macrobrachium nipponense. These nuclear morphological variations could be regarded as an important classifying property among Decapoda, on which, studies could contribute much to the analysis of the status of this species in the reproductive evolution of Caridean shrimp.

Both spontaneous and induced germ cell apoptosis occur during the process of germ cell differentiation in testis, which is an important mechanism to remove surplus and abnormal germ cells. It has been known that germ cell apoptosis is under the control of endocrine, cell social association and gene. To elucidate the molecular mechanisms by which germ cell apoptosis is regulated and the elements of the death machinery will provide a basis for effective management of male infertility as well as more targeted approaches to male contraception.

Objective: To investigate the variation of rat androgen binding protein (ABP) mRNA in sertoli cell of rat testis during spermatogenesis., Methods: In situ hybridization was performed with digoxin-labeled rat ABP cDNA probe on frozen testis tissue sections from SD rats. The expression of ABP mRNA was quantified by using laser density scanning system., Results: It was shown that ABP mRNA levels were low from stage I to stage VI, increased to the peak level at the stages VII-VIII, and then declined rapidly at stages IX-XI. Thereafter, ABP mRNA levels increased again at stages XII-XIV, and then decreased to the lowest level at stages I-VI., Conclusions: ABP mRNA level was stage-dependent during the spermatogenic cycle.

Objective: To study the effect of testosterone on spermatogenesis., Methods: Testosterone concentrations were measured in testicular interstitial fluid (IF), and serum sample from the testicular artery, testicular veins on the surface of the testis, and the peripheral venous, inferior vena cave and proximal spermatic veins in adult SD rats. The left and bilateral veins at the proximal end of the spermatic cord were ligated respectively. Testosterone concentrations and weight of the testis were measured, and the changes of the testicular morphology were studied 3 days and 21 days after ligation respectively., Results: The testosterone concentrations were highest in IF. The serum testosterone concentrations were highest in the testicular veins on the surface of the testis. The serum testosterone concentrations in the proximal spermatic veins, the testicular artery, the peripheral venous and inferior vena cave were (42.503 +/- 12.749), (42.503 +/- 12.749), (5.598 +/- 3.649), (2.533 +/- 1.719) and (2.418 +/- 1.495) mg/L respectively. Three days after the proximal spermatic veins were ligated bilaterally, the weights of the testis and the serum testosterone concentrations declined markedly. The epithelium of the seminiferous tubules degenerated slightly and part of the structure was indistinct. Three days after the left proximal spermatic veins were ligated, the weights of the left testis, the testosterone concentrations in the left IF and in the serum of the left testicular artery declined distinctly except the serum testosterone concentration of the peripheral venous, inferior vena cave and those of the right testis. The epithelium of the seminiferous tubules in the left testis degenerated slightly and part of the structure was indistinct. It was restored 21 days after ligation., Conclusions: A "small circulation" (testis-the testicular veins-the spermatic veins-the spermatic artery-the testicular artery-testis) may exist. The results indicate that after ligation of the proximal spermatic veins, the reduction of the testosterone concentrations and changes of testicular morphology is temporary and may be recovered.