Proliferative and Apoptotic Pathways in the Testis of Quail Coturnix coturnix during the Seasonal Reproductive Cycle

Elevated temperature affects the expression of signaling molecules in quail testes meiosis I prophase, but spermatogenesis remains normal

Spermatogenesis in eukaryotes is a process that occurs within a very narrow temperature threshold, typically not exceeding 36 °C. SPO11 was isolated from the temperature-sensitive mutant receptor of Saccharomyces cerevisiae and is thought to be the only protein that functions during meiosis. This suggested that SPO11 may be the key protein that influenced the temperature of spermatogenesis not exceeding 36 °C. Elevated temperatures typically damage the spermatogenic cells. Birds have a core body temperature of 41-42 °C, and their testis are located inside their bodies, providing an alternative perspective to investigate the potential impact of temperature threshold on spermatogenesis. The objective of this study was to ascertain whether elevated ambient temperatures affect spermatogenesis in birds and whether SPO11 is the key gene affecting the temperature threshold for spermatogenesis. STRA8, SCP3, SPO11, γ-H2AX, and RAD51 were all crucial components in the process of meiotic initiation, synapsis, DNA double-strand break (DSB) induction, homologous chromosome crossover recombination, and repair of DSB. In this study, 39-day-old Japanese quail were subjected to heat stress (HS) at 38 °C for 8 h per day for 3 (3d HS) and 13 (13d HS) consecutive days and analyzed the expression of meiotic signaling molecules (STRA8, SCP3, SPO11, γ-H2AX, and RAD51) using molecular biology techniques, including Immunohistochemistry (IHC), Western Blot (WB), and Real-time Quantitative Polymerase Chain Reaction (qRT-PCR). We found that spermatogenesis was normal in both groups exposed to HS. Meiotic signaling molecules were expressed normally in the 3d HS group. All detected signaling molecules were normally expressed in the 13d HS group, except for SPO11, which showed a significant increase in expression, indicating that SPO11 was temperature-sensitive. We examined the localized expression of each meiotic signaling molecule in quail testis, explored the temperature sensitivity of SPO11, and determined that quail testis can undergo normal spermatogenesis at ambient temperatures exceeding 36 °C. This study concluded that SPO11 is not the key protein influencing spermatogenesis in birds. These findings enhance our understanding of avian spermatogenesis.

Glyphosate Exposure Induces Cytotoxicity, Mitochondrial Dysfunction and Activation of ERα and ERβ Estrogen Receptors in Human Prostate PNT1A Cells

Glyphosate, the active ingredient of several broad-spectrum herbicides, is widely used throughout the world, although many adverse effects are known. Among these, it has been recognized as an endocrine disruptor. This work aimed to test the effects and potential endocrine disrupting action of glyphosate on PNT1A human prostate cells, an immortalized non-tumor epithelial cell line, possessing both ERα and ERβ estrogen receptors. The results showed that glyphosate induces cytotoxicity, mitochondrial dysfunction, and rapid activation of ERα and ERβ via nuclear translocation. Molecular analysis indicated a possible involvement of apoptosis in glyphosate-induced cytotoxicology. The apoptotic process could be attributed to alterations in mitochondrial metabolism; therefore, the main parameters of mitochondrial functionality were investigated using the Seahorse analyzer. Impaired mitochondrial function was observed in glyphosate-treated cells, with reductions in ATP production, spare respiratory capacity, and proton leakage, along with increased efficiency of mitochondrial coupling. Finally, the results of immunofluorescence analysis demonstrated that glyphosate acts as an estrogen disruptor determining the nuclear translocation of both ERs. Nuclear translocation occurred independent of dose, faster than the specific hormone, and persisted throughout treatment. In conclusion, the results collected show that in non-tumor prostate cells glyphosate can cause cell death and acts as a xenoestrogen, activating estrogen receptors. The consequent alteration of hormonal functions can have negative effects on the reproductive health of exposed animals, compromising their fertility.

Cocaine Effects on Reproductive Behavior and Fertility: An Overview

Cocaine is one of the most widely used drugs that, due to its molecular properties, causes various behavioral alterations, including sexual behavior. In vivo and in vitro studies conducted mainly in mammals have shown various disorders of sexual activity and morpho-functional dysfunctions of the gonads in both sexes. Although the modalities are still unclear, cocaine has been shown to alter the cell cycle, induce apoptosis, and alter sperm motility. In females, this drug alters the formation of the meiotic spindle as well as may obstruct the ovulation mechanism of mature oocytes. The data provided in this review, in addition to reviewing the current literature on the main effects of cocaine on spermatogenesis and oogenesis mainly in mammals, will hopefully provide a basic overview that may help and support further future studies on the molecular interaction of cocaine and its metabolites with germ cells.

Alterations in gonadotropin, prolactin, androgen and estrogen receptor and steroidogenesis-associated gene expression in gander testes in relation to the annual period

Physiological mechanisms of seasonal changes in testicular function in birds are not fully elucidated. The balance between androgens and estrogens and testis sensitivity for gonadotropin and gonadal steroids are still unclear. The aim of the study was to examine: (1) the changes in circulating and intra-testicular steroid hormone levels and their relationship; (2) the mRNA expression of testicular gonadotropin, prolactin (PRL), progesterone (P4), androgen, and estrogen receptors, and (3) key steroidogenesis processes-related genes with immunofluorescent localization of aromatase in gander testes during the annual period. Testes from ganders (n = 25) in the first reproduction season were obtained at five breeding stages, i.e., prebreeding (PrB), peak of reproduction (PR), postbreeding (PoB), nonbreeding (NB), and onset of reproduction (OR). Males were kept under breeding conditions. It was found that plasma P4 levels decreased at the PoB and NB stages, whereas intra-testicular P4 was the highest in the NB stage. Intra-testicular estradiol (E2) levels were higher at the PoB and NB stages than the other stages, whereas testosterone (T) levels showed a nearly opposite pattern. The plasma estradiol-to-testosterone ratios were higher at the PrB, PoB and NB stages compared to other stages. The transcript abundances for luteinizing hormone receptor (LHR), PRL receptor (PRLR), estrogen receptor alpha (ERα), and estrogen receptor beta (ERβ) also change in testicular tissue during the annual period. Moreover, StAR mRNA expression was upregulated at the PoB and NB stages, and CYP11A1 transcript level was the highest at the PoB stage. Stage-dependent changes in the CYP19A1 mRNA and aromatase protein levels with higher abundances of transcript at PoB and NB stages and protein at the NB stage were observed. Localization and immunofluorescent signal intensity for aromatase also differed in relation to the examined stages. It may be suggested that differential E2 levels, as well as aromatase expression and localization across annual stages are responsible for the seasonal activation/inactivation stages of testis spermatogenesis in domestic ganders. These data strongly suggest a role of aromatase in the control of gander steroidogenesis as changes in this enzyme level are associated with alternation in gonadal steroid hormones. In addition, joint action with others hormones, like PRL and LH, seems to be important in the final effect of seasonal reproduction potential.

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

Simple Summary

The 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.

Abstract

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.

Molecular and Histological Effects of Glyphosate on Testicular Tissue of the Lizard Podarcis siculus

The expansion of agriculture produces a steady increase in habitat fragmentation and degradation due to the increased use of pesticides and herbicides. Habitat loss and alteration associated with crop production play an important role in reptile decline, among which lizards are particularly endangered. In this study, we evaluated testicular structure, steroidogenesis, and estrogen receptor expression/localization after three weeks of oral exposure to glyphosate at 0.05 and 0.5 μg/kg body weight every other day in the field lizard Podarcis siculus. Our results show that glyphosate affected testicular morphology, reduced spermatogenesis, altered gap junctions and changed the localization of estrogen receptors in germ cells, increasing their expression; the effects were mostly dose-dependent. The result also demonstrates that glyphosate, at least at these concentrations, did not influence steroidogenesis. Overall, the data indicate that this herbicide can disturb the morphophysiology of the male lizard's reproductive system, with obviously detrimental effects on their reproductive fitness. The effects of glyphosate must be considered biologically relevant and could endanger the reproductive capacity not only of lizards but also of other vertebrates, including humans; a more controlled and less intensive use of glyphosate in areas devoted to crop production would therefore be advisable.