Spermatogenesis Research Papers - Academia.edu (original) (raw)

Purpose: We explored the efficacy of selenium and/or or N-acetyl-cysteine for improving semen parameters in infertile men, and the associations among semen quality and the concentrations of selenium and N-acetyl-cysteine in seminal... more

Purpose: We explored the efficacy of selenium and/or or N-acetyl-cysteine for improving semen parameters in infertile men, and the associations among semen quality and the concentrations of selenium and N-acetyl-cysteine in seminal plasma. Materials and Methods: The study included 468 infertile men with idiopathic oligo-asthenoteratospermia who were randomized to receive 200 g selenium orally daily (selenium group of 116), 600 mg N-acetyl-cysteine orally daily (N-acetyl-cysteine group of 118), 200 g selenium plus 600 mg N-acetyl-cysteine orally daily (selenium plus N-acetyl-cysteine group of 116) or similar regimen of placebo (control group of 118) for 26 weeks, followed by a 30-week treatment-free period. These patients provided blood samples for the measurement of serum testosterone, estradiol, follicle-stimulating hormone, luteinizing hormone, prolac-tin, inhibin B, selenium and N-acetyl-cysteine. Semen samples were also obtained for routine semen analysis, and the measurement of seminal plasma selenium and N-acetyl-cysteine. Results: In response to selenium and N-acetyl-cysteine treatment serum follicle-stimulating hormone decreased but serum testosterone and inhibin B increased. All semen parameters significantly improved with selenium and N-acetyl-cys-teine treatment. Administering selenium plus N-acetyl-cysteine resulted in additive beneficial effects. A significant positive correlation existed between the seminal plasma concentrations of selenium and N-acetyl-cysteine, and semen parameters. A strong correlation was observed between the sum of the selenium and N-acetyl-cysteine concentrations, and mean sperm concentration (r ϭ 0.67, p ϭ 0.01), sperm motility (r ϭ 0.64, p ϭ 0.01) and percent normal morphology (r ϭ 0.66, p ϭ 0.01). Conclusions: These results indicate that supplemental selenium and N-acetyl-cysteine improve semen quality. We advocate their use for male infertility treatment. Abbreviations and Acronyms E2 ϭ estradiol FSH ϭ follicle-stimulating hormone GSH ϭ glutathione LH ϭ luteinizing hormone NAC ϭ N-acetyl-cysteine PRL ϭ prolactin RIA ϭ radioimmunoassay assay ROS ϭ reactive oxygen species TEAE ϭ treatment emergent adverse event

This is a report of a 6-year follow-up of a male patient's semen parameters during heavy chronic alcohol intoxication and after withdrawal. A slowly progressive negative impact of alcohol could be observed: isolated moderate... more

This is a report of a 6-year follow-up of a male patient's semen parameters during heavy chronic alcohol intoxication and after withdrawal. A slowly progressive negative impact of alcohol could be observed: isolated moderate teratozoospermia was firstly noted followed by oligoasthenoteratospermia. Then a severe worsening resulted in cryptozoospermia and ultimately in azoospermia. At this moment, the histological analysis of a testicular biopsy revealed a maturation arrest of the germinal cells at the pachytene stage with no mature sperm cells. Alcohol withdrawal was then obtained, allowing a very fast and drastic improvement of semen characteristics; strictly normal semen parameters were observed after no more than 3 months. Taking into consideration these data, patients should be questioned about their alcohol intake before assisted reproductive technology and should be informed about this adverse effect. Moreover, this case report emphasizes how quickly benefits can be obtaine...

In the present work, the effect of exposure to cigarette smoke on male fertility in rats, as characterized by changes in the relative weight of sex organs, epididymal sperm count, activity of marker enzymes and DNA damage was evaluated.... more

In the present work, the effect of exposure to cigarette smoke on male fertility in rats, as characterized by changes in the relative weight of sex organs, epididymal sperm count, activity of marker enzymes and DNA damage was evaluated. Exposure of rats to cigarette smoke caused a gradual decrease in total body weight gain and relative weight of the epididymis and seminal vesicles by 30 and 40% respectively. Epididymal sperm count was reduced significantly by 25% (P 0.05) after 2 weeks and by 41% (P 0.001) after 4 weeks of exposure. Exposure to cigarette smoke had reduced the activity of sorbitol dehydogenase by 18% (P < or = 0.05) and increased the activity of lactate dehydrogenase by 28% (P < or = 0.05). The changes in both key enzymes were significant, which reflected the inhibitory effect of cigarette smoke on spermatogenesis and sperm maturation. The toxic effect of exposure could be explained partially due to induction of DNA damage and oxidative stress as shown by the s...

The safety of different doses of Kan Jang™ – a fixed combination of Andrographis paniculata special extract (SHA-10) and Acanthopanax senticosus – compared to two extensively used medicinal plants, Valeriana officinalis and Panax ginseng... more

The safety of different doses of Kan Jang™ – a fixed combination of Andrographis paniculata special extract (SHA-10) and Acanthopanax senticosus – compared to two extensively used medicinal plants, Valeriana officinalis and Panax ginseng in the form of standardized extracts, has been examined. A phase I clinical study was designed to evaluate the effect on semen quality of healthy males in terms of spermatogenesis and quality of semen. The results of the study revealed no significant negative effect of Kan Jang on male semen quality and fertility, but rather a positive trend with respect to the number of spermatozoids in the whole ejaculate, the percentage of active (normokinetic) forms of spermatozoids, and fertility indexes, together with a decrease in the percentage of inactive (diskinetic) forms of spermatozoids. In the group receiving ginseng, no significant negative effects on the fertility parameters were revealed and there was a clear decrease in the percentage of diskinetic forms of spermatozoids. Subjects receiving valerian showed a temporary increase in the percentage of normokinetic spermatozoids and a decrease in diskinetic forms, but these changes had no effect on fertility indices. The results indicate that Kan Jang, ginseng and valerian are safe with respect to effects on human male sterility when administered at dose levels corresponding to approximately 3 times the human daily dose.

The study investigated the effect of Parateq on gonad morphology and changes in gonadosomatic index of post fingerlings of Tilapia guineensis exposed to sublethal Parateq concentrations for 12 weeks. Initial short- term static toxicity... more

The study investigated the effect of Parateq on gonad morphology and changes in gonadosomatic index of post fingerlings of Tilapia guineensis exposed to sublethal Parateq concentrations for 12 weeks. Initial short- term static toxicity tests were run to determine 96 hr LC50 of Parateq in T. guineensis which was 5.47%. The Parateq concentrations used were 0.32%, 0.63%, 1.25 % and 2.5% vol/vol parateq/ water. The histological changes noted in the gonads of the exposed fish were inhibition of maturation in oocytes or delay in spermatogenesis which resulted in lack of spawning. In contrary, the four stages of spermatogenesis or oocytogenesis were present in the control and spawning occurred. The increasing degeneration of maturing eggs resulted in complete absence of matured egg in the female gonads of fish exposed to the highest concentration (2.5%) of the drilling fluid. The gonadal somatic index values were recorded in a decreasing order toward the higher tested concentrations. The g...

To manage male infertility caused by hormonal imbalance, infections and other predicaments, multifarious treatment strategies are emerging worldwide. Contemporary treatments, such as assisted reproductive techniques, are costly with low... more

To manage male infertility caused by hormonal imbalance, infections and other predicaments, multifarious treatment strategies are emerging worldwide. Contemporary treatments, such as assisted reproductive techniques, are costly with low success rates of only 10-30%; however, herbal remedies are gaining more attention as an alternative or supplementary therapeutic modality for male infertility. The beneficial effects induced by oral intake of the roots of a small evergreen shrub, Withania sominifera (Ashwagandha) on semen quality of infertile men have previously been studied. Oral intake of Ashwagandha roots has been found to inhibit lipid peroxidation, improve sperm count and motility, and regulate reproductive hormone levels. The molecular mechanisms of these effects, however, are yet to be unveiled.

To control the population explosion in the world, new methods of contraception involving men is an attractive alternative. Since ancient times, plants and plant based products have been used as a valuable and safe natural source of... more

To control the population explosion in the world, new methods of contraception involving men is an attractive alternative. Since ancient times, plants and plant based products have been used as a valuable and safe natural source of medicines for treating various ailments. India possesses a vast reserve of medicinal plants which have been used extensively in the treatment of various diseases. The reversibility of antifertility effects of plants and its active components, play a major role in development of male contraceptive agents. The present review attempts to discuss medicinal effects of plant derived products on male reproductive system.

The Sertoli cell received its family name in a paper published by von Ebner [1] in which he described the cells as “the cells of Sertoli.” It is amazing that the early scientists were able to deduce the cell’s basic structure so well,... more

The Sertoli cell received its family name in a paper published by von Ebner [1] in which he described the cells as “the cells of Sertoli.” It is amazing that the early scientists were able to deduce the cell’s basic structure so well, especially when consideration is given to the poor resolution of microscopes in the 1800s (see Chapter 1) and the lack of proper fixation, embedding, sectioning, and staining. In fact, Sertoli’s original observations were so intuitive that few scientists at that time bothered to study the cell in great depth, because most everyone accepted his descriptions and went on to other more important topics of the day.
Most scientists waited for the improved resolution provided by the electron microscope before returning to the study of the Sertoli cell. From 1865, when Sertoli published his famous observations, until 1950, approximately 85 manuscripts were published with Sertoli cell or other descriptive names for this cell in the title or as key words. Then in 1953 the first paper to observe the testis with the transmission electron microscope was published [2]. However, it was most likely the work of Don Fawcett at Harvard in the 1950s [3, 4] that firmly established the importance of study- ing Sertoli cell morphology, because from 1951 until 1973, the year that Lonnie Russell published his first manuscript on testicular morphology [5], the number of publications dealing with the Sertoli cell jumped to approximately 440. From 1973 to 1990, about 4000 Sertoli cell papers were published, which is an indica- tion of the recognition of the importance of Sertoli cells in testicular function. Such growth in Sertoli cell inter- est is a direct result of the tremendous impact that morphological studies, especially those of Dr. Russell, have had on the reproductive sciences.

The blood-testis barrier (BTB) is known for its ability to create an immune privilege site in the seminiferous epithelium, but less is known of the blood-epididymal barrier (BEB). It is already established that the fully functional BTB... more

The blood-testis barrier (BTB) is known for its ability to create an immune privilege site in the seminiferous epithelium, but less is known of the blood-epididymal barrier (BEB). It is already established that the fully functional BTB and BEB are much more complex and consist of anatomical/physical (tight junctions, basolateral and apical membranes), physiological and immunological components, which are all necessary to make a functioning barrier in the testis and epididymis. However, comparative data for metazoans suggest that an effective Sertoli cell barrier is not entirely necessary for the development of germ cells during spermatogenesis or that our knowledge about the barrier structure/function in metazoans is still immature. This chapter compares the unique barrier formed by the Sertoli cells of the testis to that formed by the apical junctional complexes of the epididymal epithelium.

It is concluded that in the birds which have been studied there is a well-defined, regular cycle of the seminiferous epithelium, and that spermatogenesis involves synchronization of the activities of germ cells within and between... more

It is concluded that in the birds which have been studied there is a well-defined, regular cycle of the seminiferous epithelium, and that spermatogenesis involves synchronization of the activities of germ cells within and between successive generations to produce cellular associations of the seminiferous epithelium which are essentially similar to those described in mammals. However, the area of a cellular association is smaller in birds than in most (and probably all) mammals so that numerous cellular associations are present in a cross-section of a seminiferous tubule. As in primates, in which a cellular association also covers a small area of seminiferous tubule, the wave of spermatogenesis in the Japanese quail follows a spiral path along and around a seminiferous tubule with consecutive stages of the cycle always occurring as adjacent stages along the tubule. The literature indicates that there are fewer mitotic divisions during spermatogonial proliferation in birds than has be...

Numerous and extensive reviews have been written about basic morphology of the mammalian Sertoli cell [1 9]. The purpose of this chapter is not to repeat all that has been covered in the past, but rather to ask how do we deal with the... more

Numerous and extensive reviews have been written about basic morphology of the mammalian Sertoli cell [1 9]. The purpose of this chapter is not to repeat all that has been covered in the past, but rather to ask how do we deal with the plethora of new data being generated using morphological techniques previously unavailable in the study of this cell [10]. The first book, titled The Sertoli Cell, was filled with photomicrographs illustrating Sertoli cell morphology [11], which was an appropri- ate tribute to Enrico Sertoli, the first scientist to publish drawings of the cell, later to be given his family name [12 14]. It took nearly an additional 100 years before electron microscopy revealed the intricate complexities of the Sertoli cell within the seminiferous epithelium [15]. The second book, Sertoli Cell Biology, included a review of the morphological variations in cellular organelles [9]; however, much of the book was devoted to Sertoli cell physiology and molecular biology [16]. So, with regard to Sertoli cell anatomy, what has changed during the past 10 years?
Basic Sertoli cell anatomy began with crude drawings published in 1865 [9,13], showing cellular extensions, described as “. . .branched out that touch two cells. . .” and holding germ cells in “...the canaliculi, or free, and still shut away in the mother cells.” Thus, the concept of “cellule madri” or “mother cell” was born and subsequent publications have shown the finer details, with descriptions of the Sertoli cell as “...not unlike trees...” with their cytoplasmic arms surrounding germ cells like long branches [17].

Spermatogonial stem cells (SSCs) are a subset of undifferentiated spermatogonia responsible for ongoing spermatogenesis in mammalian testes. SSCs arise from morphologically homogeneous prospermatogonia, but growing evidence suggests that... more

Spermatogonial stem cells (SSCs) are a subset of undifferentiated spermatogonia responsible for ongoing spermatogenesis in mammalian testes. SSCs arise from morphologically homogeneous prospermatogonia, but growing evidence suggests that only a subset of prospermatogonia develops into the foundational SSC pool. This predicts that subtypes of undifferentiated spermatogonia with discrete mRNA and protein signatures should be distinguishable in neonatal testes. We used single-cell qRT-PCR to examine mRNA levels of 172 genes in individual spermatogonia from 6-day postnatal (P6) mouse testes. Cells enriched from P6 testes using the StaPut or THY1+ magnetic cell sorting methods exhibited considerable heterogeneity in the abundance of specific germ cell and stem cell mRNAs, segregating into one somatic and three distinct spermatogonial clusters. However, P6 Id4-eGFP+ transgenic spermatogonia, which are known to be enriched for SSCs, were more homogeneous in their mRNA levels, exhibiting un...

Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and... more

Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG) axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn could help in the management of male infertility.

Gonad development requires a coordinated soma-germline interaction that ensures renewal and differentiation of germline and somatic stem cells to ultimately produce mature gametes. The Drosophila tumour suppressor gene discs large (dlg)... more

Gonad development requires a coordinated soma-germline interaction that ensures renewal and differentiation of germline and somatic stem cells to ultimately produce mature gametes. The Drosophila tumour suppressor gene discs large (dlg) encodes a septate junction protein functioning during epithelial polarization, asymmetric neuroblast division, and formation of neuromuscular junctions. Here, we report the role of dlg in testis development and its critical function in somatic cyst cells (SCCs). In these cells dlg is primarily required for their survival and expansion, and contributes to spermatocyte cyst differentiation. Cell death primarily occurred in SCCs at the end of spermatogonial amplification at a time when Dlg becomes restricted in wild-type (wt) testes to the distal somatic cells capping the growing spermatocyte cysts. RNAi depletion of dlg transcripts in early SCCs fully prevented testis development, whereas depletion in late SCCs resulted in a breakdown of spermatocyte cyst structure and germ cell individualization. Specific dlg expression in SCCs resulted in developmental rescue of dlg mutant testes, whereas its expression in germ cells exerted no such effect. dlg overexpression in wt testes led to spermatocyte cyst expansion at the expense of spermatogonial cysts. Our data demonstrate that dlg is essentially required in SCCs for their survival, expansion, and differentiation, and for the encapsulation of the germline cells.