Spermatocyte Stage Research Articles

Behavioral Assessment Reveals GnRH Immunocastration as a Better Alternative to Surgical Castration.

Castration is often employed in animal management for reproductive control. However, it is important to evaluate its impact on animal welfare. In this study, we developed rat models for both surgical (n = 6) and GnRH immunocastration (n = 6) to assess the effects of these castration methods on physiological and behavioral characteristics. The novel GnRH-based vaccine significantly increased serum GnRH antibody levels and drastically reduced testosterone, with the testes shrinking to one-fifth the size of those in the control group, thereby halting spermatogenesis at the secondary spermatocyte stage. Behavioral evaluations demonstrated that sexual behavior was significantly suppressed in both surgically and immunologically castrated groups compared to the control, confirming the effectiveness of both methods. However, psychological tests revealed significant signs of depression and social deficits in the surgically castrated group, whereas the behavior of the GnRH-immunocastrated group did not significantly differ from the control. Furthermore, no significant differences in learning and memory were observed among the three groups in the water maze test. Compared to surgical castration, GnRH immunocastration offers effective results and better animal welfare, providing a more humane alternative for livestock management.

Diverse somatic Transformer and sex chromosome karyotype pathways regulate gene expression in Drosophila gonad development.

The somatic sex determination gene transformer (tra) is required for the highly sexually dimorphic development of most somatic cells, including those of the gonads. In addition, somatic tra is required for the germline development even though it is not required for sex determination within germ cells. Germ cell autonomous gene expression is also necessary for their sex determination. To understand the interplay between these signals, we compared the phenotype and gene expression of larval wild-type gonads and the sex-transformed tra gonads. XX larval ovaries transformed into testes were dramatically smaller than wild-type, with significant reductions in germ cell number, likely due to altered geometry of the stem cell niche. Additionally, there was a defect in progression into spermatocyte stages. XY larval testes transformed into ovaries had excessive germ cells, possibly due to the earlier onset of cell division. We suggest that germ cells are neither fully female nor male following somatic sex transformation, with certain pathways characteristic of each sex expressed in tra mutants. We found multiple patterns of somatic and germline gene expression control exclusively due to tra, exclusively due to sex chromosome karyotype, but usually due to a combination of these factors showing tra and sex chromosome karyotype pathways regulate gene expression during Drosophila gonad development.

P-069 The expression patterns of ALOX15 and GPX4 in the seminiferous epithelium of men with non-obstructive azoospermia (NOA) due to primary testicular failure

Abstract Study question Does the expression of ALOX15 and GPX4 differ in NOA men with a history of cryptozoospermia from NOA who never had sperm in their ejaculate? Summary answer There was no significant difference between these 2 groups of patients. What is known already Oxidative stress (OS) has been investigated as a prime suspect for many unexplained pathologies, including primary testicular failure (PTF). The fact that male germ cells are rich in polyunsaturated fatty acids (PUFAs) but have a limited amount of cytoplasmic scavenging enzymes, is the reason behind their extreme vulnerability to OS. The accumulation of lipid peroxidation markers leads to the inactivation of glutathione peroxidase 4 (GPX4), the lipid repair enzyme, and the exacerbation of arachidonate 15-lipoxygenase (ALOX15), a lipoxygenase enzyme that promotes lipid degradation. This study investigates the activity of these antagonizing enzymes in the testicular tissue of NOA patients. Study design, size, duration This observational study was conducted in the period from May 2020, following the Ethics Committee of the University of Split School of Medicine approval, to October 2023. The testicular tissue from 57 patients diagnosed with NOA (according to WHO criteria) and referred to their first microTESE as a part of fertility treatment was collected and processed. Participants/materials, setting, methods Samples were prepared for histological evaluation and immunodetection (fixation; embedding in paraffin; H&E staining; and staining with anti-ALOX15 and anti-GPX4 antibodies). Two groups of NOA patients were observed: Crypto-NOA and NOA group. The main outcome measure was the number of ALOX15 positive germ cells per 1 mm² of the seminiferous tubule surface (N/ mm²) and the percentage (%) of GPX4 positive surface per surface of the tubule measured by the ImageJ program. Main results and the role of chance Spermatozoa were retrieved in 37 of 57 (64,91 %) men; samples of 4 patients had to be excluded due to poor fixation. There were 18 patients in the Crypto-NOA group, and 10 in the NOA group, while 5 patients were diagnosed with obstructive azoospermia (OA) and were used as controls. For comparison of the baseline data of Crypto-NOA and NOA patients, we used the Mann-Whitney test, and with statistical significance set at the level of P < 0.05, we found that there were significantly more patients with cryptorchism in the NOA group. As a tool for histological evaluation, we used the diagnostic code designed by McLachlan et al. and found similar spermatogenic phenotypes between Crypto NOA and NOA patients. The most represented phenotype was hypospermatogenesis with a moderate reduction in late spermatid number mixed with normal tubules (38,8 % in Crypto-NOA; 40% in NOA), following the phenotype where late spermatids are present in some tubules but mixed with tubules showing no progression past the spermatocyte stage. Using the Mann-Whitney test, we did not find a significant difference in the expression of ALOX15 and GPX4 in the seminiferous epithelium of Crypto-NOA and NOA patients. Limitations, reasons for caution The testicular tissue of NOA patients is characterized by focal or patchy spermatogenesis which led to the exclusion of several samples due to the fixation of tissue with a homogenous pattern of Sertoli cell-only or germ-cell arrest. Wider implications of the findings This study will provide additional information regarding the cause of impaired spermatogenesis and help to determine if the patient is a potential candidate for antioxidant therapy. Our next step is to associate the expression patterns of ALOX15 and GPX4 with the success rates of in vitro fertilization procedure outcomes. Trial registration number not applicable

Using Selenium-enriched Mutated Probiotics as Enhancer for Fertility Parameters in Mice.

Increasing fertility rates have become one of the factors that concern all people in the world. Therefore, the study aims to use two mutated strains of probiotics enriched with selenium (PSe40/60/1 and BSe50/20/1) to improve fertility. Thirty Swiss albino male mice were divided into three groups; control, LP + S was given Lactobacillus plantarum PSe40/60/1 plus selenium, and BL + S was given Bifidobacterium longum BSe50/20/1 plus selenium. Free testosterone, LH, and FSH were measured in serum by biochemical analysis. Testicular tissues were examined by histopathological analysis. The count and motility of sperm, and sperm abnormalities were determined by microscopic examination. The method of qRT-PCR was used to detect gene expression of Tspyl1, Hsd3b6, and Star genes. The biochemical results showed that serum content of free testosterone (FT) hormone had significantly increase in the BL + S and LP + S groups compared with control. Levels of LH and FSH hormones were the highest in the BL + S group. The treated groups showed all developmental stages of spermatogenesis, including spermatogenesis, spermatocytes, and seminiferous tubule spermatids, as well as intact Sertoli cells and Leydig cells without changes. When compared to the control group, sperm count and motility increased in the BL + S group, while sperm abnormalities decreased. The expression of Tspyl1 gene in testicular tissues decreased in the LP + S and BL + S groups, while the expression of Star and Hsd3b6 genes was higher in the BL + S group and lower in the LP + S group compared with the control group. Therefore, Bifidobacterium longum BSe50/20/1 enriched with selenium could be useful in enhancing male fertility.

MRNA-Seq of testis and liver tissues reveals a testis-specific gene and alternative splicing associated with hybrid male sterility in dzo.

Alternative splicing (AS) plays an important role in the co-transcription and post-transcriptional regulation of gene expression during mammalian spermatogenesis. The dzo is the male F1 offspring of an interspecific hybrid between a domestic bull (Bos taurus ♂) and a yak (Bos grunniens ♀) which exhibits male sterility. This study aimed to identify the testis-specific genes and AS associated with hybrid male sterility in dzo. The iDEP90 program and rMATS software were used to identify the differentially expressed genes (DEG) and differential alternative splicing genes (DSG) based on RNA-seq data from the liver (n = 9) and testis (n = 6) tissues of domestic cattle, yak, and dzo. Splicing factors (SF) were obtained from the AmiGO2 and the NCBI databases, and Pearson correlation analysis was performed on the differentially expressed SFs and DSGs. We focused on the testis-specific DEGs and DSGs between dzo and cattle and yak. Among the top 3,000 genes with the most significant variations between these 15 samples, a large number of genes showed testis-specific expression involved with spermatogenesis. Cluster analysis showed that the expression levels of these testis-specific genes were dysregulated during mitosis with a burst downregulation during the pachynema spermatocyte stage. The occurrence of AS events in the testis was about 2.5 fold greater than in the liver, with exon skipping being the major AS event (81.89% to 82.73%). A total of 74 DSGs were specifically expressed in the testis and were significantly enriched during meiosis I, synapsis, and in the piRNA biosynthesis pathways. Notably, STAG3 and DDX4 were of the exon skipping type, and DMC1 was a mutually exclusive exon. A total of 36 SFs were significantly different in dzo testis, compared with cattle and yak. DDX4, SUGP1, and EFTUD2 were potential SFs leading to abnormal AS of testis-specific genes in dzo. These results show that AS of testis-specific genes can affect synapsis and the piRNA biosynthetic processes in dzo, which may be important factors associated with hybrid male sterility in dzo.

Gonadal and cellular dynamics during protogynous sex change in the harlequin sandsmelt Parapercis pulchella.

Some teleost fishes change their sex, and some of these fishes have specific gonads known as "ovotestes," that is, gonads containing both ovarian and testicular tissues. In this study, we revealed the gonadal transformation process and cell dynamics during the female-to-male sex change in the harlequin sandsmelt, Parapercis pulchella (Pinguipetidae), in which females possess ovotestes. Histological observations revealed that although female ovotestes were composed of oocytes, a few cysts of male germ cells were observed among them. At the initial phase of sex change, male germ cells increased, and spermatogenesis proceeded. After that, oocytes decreased and finally disappeared, and the gonads became functional testes. Immunohistochemistry using antibodies against Pcna (proliferating cell nuclear antigen) as a cell proliferation marker revealed that spermatogonia were Pcna positive, whereas spermatocytes were negative, in female ovotestes. This suggests that spermatogenesis is arrested at the spermatocyte stage. In addition, some somatic cells surrounding oocytes, which were thought to be the female follicle cells, were Pcna positive during sex change, indicating that these cells proliferate during sex change and are reused in male testes after sex change. Also, immunostaining using antibodies against active cleaved-Caspase3a as an apoptosis marker demonstrated that oocytes degenerated through apoptotic cell death at the late transition stage. Together with previous findings in other fishes, these findings suggested that the histological processes in gonads during sex change, such as the order of developmental events, developmental fates of ovarian cavities, and ovotestis structures, are diversified among fish species. In contrast, cellular dynamics of female germ and somatic cells during sex change are common among protogynous species.

Seasonal variations of testis anatomy and of G-coupled oestrogen receptor 1 expression in Gerbillus gerbillus.

The gerbil, Gerbillus gerbillus, a nocturnal desert rodent of northern Africa, exhibits a seasonal reproductive cycle with marked anatomical and behavioural shifts between breeding season and resting season. The aim of this study is to investigate key elements involved in these seasonal changes, specifically in males: the histology of the testis as well as the expression of the G-protein-coupled oestrogen receptor 1 (GPER1) in the testis. During the breeding season, the seminiferous tubules were full of spermatozoa, and their epithelium contained germinal cells embedded in Sertoli cells. Amidst tubules, well-developed Leydig cells were observed around blood vessels, with peritubular myoid cells providing structural and dynamic support to the tubules. GPER1 was largely expressed throughout the testis. Notably, Leydig cells, spermatogonia and spermatocytes showed strong immunohistochemical signals. Sertoli cells, spermatozoa and peritubular myoid cells were moderately stained. During the resting season, spermatogenesis was blocked at the spermatocyte stage, spermatids and spermatozoa were absent and the interstitial space was reduced. The weight of the testis decreased significantly. At this stage, GPER1 was found in Leydig cells, spermatocytes and peritubular myoid cells. Sertoli cells and spermatogonia were not marked. Overall, the testis of the gerbil, Gerbillus gerbillus, has undergone noticeable histological, cellular and weight changes between seasons. In addition, the seasonal expression pattern of GPER1, with pronounced differences between resting season and breeding season, indicates that this receptor is involved in the regulation of the reproductive cycle.

VCP promotes tTAF-target gene expression and spermatocyte differentiation by downregulating mono-ubiquitylated H2A.

Valosin-containing protein (VCP) binds and extracts ubiquitylated cargo to regulate protein homeostasis. VCP has been studied primarily in aging and disease contexts, but it also affects germline development. However, the precise molecular functions of VCP in the germline, particularly in males, are poorly understood. Using the Drosophila male germline as a model system, we find that VCP translocates from the cytosol to the nucleus as germ cells transition into the meiotic spermatocyte stage. Importantly, nuclear translocation of VCP appears to be one crucial event stimulated by testis-specific TBP-associated factors (tTAFs) to drive spermatocyte differentiation. VCP promotes the expression of several tTAF-target genes, and VCP knockdown, like tTAF loss of function, causes cells to arrest in early meiotic stages. At a molecular level, VCP activity supports spermatocyte gene expression by downregulating a repressive histone modification, mono-ubiquitylated H2A (H2Aub), during meiosis. Remarkably, experimentally blocking H2Aub in VCP-RNAi testes is sufficient to overcome the meiotic-arrest phenotype and to promote development through the spermatocyte stage. Collectively, our data highlight VCP as a downstream effector of tTAFs that downregulates H2Aub to facilitate meiotic progression.

Fine ultrastructural features of germ cells and spermatozoa during spermatogenesis in the European grayling, Thymallus thymallus (Teleostei, Salmoniformes, Salmonidae).

This study aimed to examine the ultrastructure of spermatogenic stages and mature spermatozoa in the European grayling, Thymallus thymallus. The testes were examined microscopically with a transmission electron microscope to find out details of the structure and morphology of the grayling germ cells, spermatozoa and some somatic cells. The grayling testis has a tubular shape, with cysts or clusters of germ cells within seminiferous lobules. The spermatogenic cells, including spermatogonia, spermatocytes, and spermatids, can be found along seminiferous tubules. There are electron-dense bodies in germ cells from the primary spermatogonia to secondary spermatocyte stages. These undergo mitosis to reach the secondary spermatogonia stage, when they form primary and secondary spermatocytes. Spermatids undergo three different stages of differentiation during spermiogenesis, characterized by the level of chromatin condensation, elimination of cytoplasm, and the occurrence of the flagellum. The midpiece of spermatozoa is short and contains spherical or ovoid mitochondria. The sperm flagellum has an axoneme with nine doublets of peripheral microtubules and two central microtubules. The result of this study is valuable to be used as a standard reference for germ cell development, which is of great importance to get a clear insight into the process of grayling breeding practice.

Mosaic Ring Chromosome 13 Presented with Isolated Male Infertility: Case Report.

Ring chromosomes are the result of breakage and re-union of distal ends of chromosomal arms. They have a general frequency of 1 in 50,000 and 1 in 58,000 for chromosome 13. Ring chromosome 13 is usually presented as a syndromic situation stigmatized by particular features, including developmental delay, mental retardation and CNS, skeletal or organ anomalies. As an experimental study, here we report a 31 years old male with no major phenotypic manifestation who was evaluated for azoospermia, while his karyotype revealed presence of a mosaic ring chromosome 13. He had a history of bilateral varicocelectomy and no other major finding in his routine infertility work up was determined. Genetic counseling did not provide any clue for mental disability or dysmorphic features. Pathology examination of the testicular tissue revealed very scarce number of spermatid/spermatozoa within the tubules in conjunction with degrees of maturation arrest mostly in spermatocyte stage. In our knowledge, this is the first report of a ring chromosome 13, manifested by an isolated male infertility.

Bi-allelic MEI1 variants cause meiosis arrest and non-obstructive azoospermia.

Non-obstructive azoospermia (NOA) is characterized by the failure of sperm production due to testicular disorders and represents the most severe form of male infertility. Growing evidences have indicated that gene defects could be the potential cause of NOA via genome-wide sequencing approaches. Here, bi-allelic deleterious variants in meiosis inhibitor protein 1 (MEI1) were identified by whole-exome sequencing in four Chinese patients with NOA. Testicular pathologic analysis and immunohistochemical staining revealed that spermatogenesis is arrested at spermatocyte stage, with defective programmed DNA double-strand breaks (DSBs) homoeostasis and meiotic chromosome synapsis in patients carrying the variants. In addition, our results showed that one missense variant (c.G186C) reduced the expression of MEI1 and one frameshift variant (c.251delT) led to truncated proteins of MEI1 in in vitro. Furthermore, the missense variant (c.T1585A) was assumed to affect the interaction between MEI1 and its partners via bioinformatic analysis. Collectively, our findings provide direct genetic and functional evidences that bi-allelic variants in MEI1 could cause defective DSBs homoeostasis and meiotic chromosome synapsis, which subsequently lead to meiosis arrest and male infertility. Thus, our study deepens our knowledge of the role of MEI1 in male fertility and provides a novel insight to understand the genetic aetiology of NOA.

New perspectives on fertility in transwomen with regard to spermatogonial stem cells.

Germ cells of transwomen are affected by gender-affirming hormone therapy (GAHT). Fertility will be lost after surgical intervention; thereby, fertility preservation becomes an increasingly imortant topic. This study investigated if the absolute number of spermatogonia in transwomen is comparable at the time of gender-affirming surgery (GAS) to that in pre-pubertal boys. We carried out a retrospective study of testicular tissues from 25 selected subjects, which had undergone a comparable sex hormone therapy regimen using cyproterone acetate (10 or 12.5 mg) and estrogens. As controls, testicular biopsies of five cisgender adult men (aged 35-48 years) and five pre-/pubertal boys (5-14 years) were included. Testicular tissues were immunohistochemically stained for MAGE A4-positive cells, the most advanced germ cell type. The number of spermatogonia per area was assessed. Clinical values and serum hormone values for FSH, LH, testosterone, free testosterone, estradiol and prolactin were determined on the day of GAS for correlation analyses. Round spermatids were the most advanced germ cell type in 3 subjects, 5 had an arrest at spermatocyte stage, while 17 showed a spermatogonial arrest. On average, testicular tissues of transwomen contained 25.15 spermatogonia/mm3, a number that was significantly reduced compared to the two control groups (P < 0.01, adult 80.65 spermatogonia/mm3 and pre-/pubertal boys 78.55 spermatogonia/mm3). Linear regression analysis revealed that testes with higher weight and high LH contained more spermatogonia. Irrespective of treatment dose or duration, spermatogenesis was impaired. Spermatogonial numbers were significantly reduced in transwomen compared to the control groups. When transwomen go through treatment to confirm their gender, their germ cells are affected. They lose their fertility after surgery, so fertility preservation becomes an important topic. We carried out a study looking at tissue from testes of 25 people who had been through the same sex hormone therapy until surgery. Blood samples were also taken. As controls, samples were taken from the testes of cisgender boys and adult men. On average, the samples from the testes of transwomen contained a smaller number of early sperm cells compared to the two control groups. Regardless of the dose or length of hormone treatment, the fertility of transwomen was significantly reduced so that counseling about fertility preservation should be offered before hormone therapy.

Морфологический анализ семенников в оценке фертильности мышей после однократного острого γ-облучения разными дозами

Introduction. Radiation therapy for malignant neoplasms can have detrimental effects on male reproductive health. Little is known about the role of morphological changes in the testes when assessing the fertility after exposure to lethal and sublethal doses. The research aimed to investigate the impact of acute γ-irradiation at various doses on testicular morphology, spermatozoa, and fertility potential in mice through a comparative morphological analysis. Materials and methods. We subjected BALB/c mice to acute γ-irradiation at doses of 1 and 6 Gy using the IGUR device (Cs137, dose rate of 0.85 Gy/min). We studied the structural state of the testes and spermatozoa. Morphological examination was performed using optical microscopy of histological slides with digital microphotography (n=180). Fertility potential was assessed by mating irradiated males (n=200) with intact mature females (n=400). Results. During the course of the experiment, which lasted from 16 to 120 days, we observed significant morphological changes in the testes and spermatozoa of the experimental groups. On day 62, the number of seminiferous tubules exhibiting destruction at 1- and 6-Gy doses was the highest. This destruction was characterized by a 2- to 4-fold increase in the desquamation of germ cells, a 3- to 6-fold increase in the desquamation of the spermatogenic epithelium, and a 2- to 10-fold increase in the desolation of the seminiferous tubules, respectively. The maximum decrease in the number of spermatozoa was to 68 and 44% at doses of 1 and 6 Gy, respectively. The number of live spermatozoa decreased to 62% and 25%; sperm motility dropped by 21% and 100%. We detected an increase in the number of pathological forms of spermatozoa by 40% and 3 times at doses of 1 and 6 Gy, respectively. An increase in the total embryonic and induced post-implantation mortality in females fertilized by irradiated males was noted at all stages of spermatogenesis (p&lt;0.05). At a 6-Gy dose, we detected a temporary sterility at the stages of spermatids and spermatocytes. Conclusion. The degree and depth of morphological changes in the testes and spermatozoa are dose-dependent, the most pronounced changes being at a 6-Gy dose causing temporary sterility. A compensatory-restorative reaction from spermatogenesis was revealed. Keywords: γ-irradiation, spermatogenesis, spermatozoon, fertility

A biallelic loss of function variant in HORMAD1 within a large consanguineous Turkish family is associated with spermatogenic arrest.

Can the analysis of a large Turkish consanguineous family via whole exome sequencing (WES) identify novel causative genetic variation responsible for nonobstructive azoospermia (NOA) characterized by arrest at primary spermatocyte stage? WES analysis revealed a homozygous nonsense variant in HORMAD1 in three affected brothers of a Turkish family. Studying patient cohorts in small or large consanguineous families using high-throughput sequencing allows the identification of genetic causes of different pathologies, including infertility. Over the last two decades, a number of genes involved in human male infertility have been discovered, but only 14 genes have been identified as being at least moderately linked to isolated NOA or oligozoospermia in men. The study included a Turkish family comprising three brothers with NOA. Two brothers had a normal karyotype, normal hormonal levels and no Yq microdeletion. The testicular histopathology analysis revealed the complete arrest of spermatogenesis at the primary spermatocyte stage. We recruited a consanguineous Turkish family where parents were first-degree cousins and had seven children; three sons who had NOA, two sons who were fertile and two daughters for whom no information was available. Saliva samples from the index patient, his two affected brothers, parents and two nonaffected brothers (seven samples in total) were collected. Prior to WES, the index patient underwent targeted genetic testing using an infertility panel, which includes 133 infertility genes. No pathogenic variations were identified. WES was then performed on the DNA of the seven family members available. Bioinformatics analysis was performed using an in-house pipeline. Detected variants were scored and ranked, and copy number variants were called and annotated.The consequences of mutation on protein expression and localization were investigated by cell transfection followed by immunofluorescence or immunoblotting. WES revealed a homozygous nonsense variant chr1:150675797G>A; HORMAD1 (NM_032132.5): c.1021C>T, p.Gln341* in exon 13, which was confirmed in all three affected brothers. HORMAD1 encodes the HORMA domain-containing protein 1. The parents as well as the two fertile brothers were carriers of this variant. This variant may lead to the production of a truncated protein lacking the nuclear localization signal; therefore, human cells were transfected with the wild-type and mutated form, in fusion with green fluorescent protein. Immunoblotting experiments confirmed the production of a truncated HORMAD1 protein, and immunofluorescence microscopy revealed that the mutated protein displayed cytoplasmic localization while the wild type protein located to the nucleus. Altogether, our findings validate HORMAD1 as an essential genetic factor in the meiotic process in human. According to one scoring system used to evaluate the clinical validity of male infertility genes, this study would classify HORMAD1 as displaying limited clinical evidence of being involved in male infertility. However, such a score is the maximum possible when only one family is analyzed and the addition of one patient showing a pathogenic or likely pathogenic variant would immediately change this classification to 'moderate'. Thus, this report should prompt other researchers to screen patients with NOA for this genetic variant. Identification of new genetic factors involved in the human meiosis process will contribute to an improvement of our knowledge at the basic level, which in turn will allow the management of better care for infertile patients. Since Hormad1-/- knock-out female mice are also infertile, HORMAD1 could also be involved in human female infertility. Our findings have direct implications for the genetic counseling of patients and their family members. The study was funded by Fondation Maladies Rares (High Throughput Sequencing and Rare Diseases-2018, 'GenOmics of rare diseases'). The authors declare that they have no conflict of interest. N/A.

How does retinoic acid (RA) signaling pathway regulate spermatogenesis?

Male sterility is a worldwide health problem which has troubled many unfortunate families and attracted widespread attention in the field of reproduction. Retinoic acid (RA) is a metabolite of vitamin A. Previous studies have shown that insufficient intake of vitamin A can lead to male infertility. Similarly, RA-deficiency can lead to abnormal spermatogenesis in men. RA signaling is inseparable from hormone stimulation, such as FSH, testosterone and others. It can regulate spermatogenesis as well, including the proliferation and differentiation of spermatogonia, meiosis, spermiogenesis and spermiation. To promote or inhibit spermatogenesis, RA regulates Stra8, Kit, GDNF, BMP4 and other factors in various pathways. At the self-renewal stage, RA inhibits spermatogonia renewal by directly or indirectly inhibiting DMRT, GDNF and Cyclin. At the stage of differentiation and meiosis, RA controls SSC differentiation through Kit induction and Nanos2 inhibition, and controls spermatogonia meiotic entry through up- regulation of Stra8. At the stage of spermiogenesis, RARα945;, as a key regulator, regulates spermatogenesis by up regulating Stra8 while binding with RA. Although RA plays an important role in all stages of spermatogenesis, RA signaling is more important in the early stage of spermatogonia (spg) differentiation and spermatocyte(spc) meiosis. According to the principle of RA signaling that regulates spermatogenesis, we also speculate on the future clinical application of RA, such as potential induction of SSC in vitro, contraception and restoring spermatogenesis. This paper reviews the regulatory pathways of RA, and prospects the clinical applications of RA signaling in the future.

Estradiol-17 β levels as a tool for sex determination in Farmed Anguilla japonica

In this study, the levels of plasma estradiol-17β (E2) in farmed Anguilla japonica were measured to determine their sex. The analyses were performed for two different size groups (large group, Total length (TL): 61–69 cm; small group, TL: 53–60 cm). The anatomical and histological observations showed that the large group consisted of 29% males and 71% females; the small group, 54% males and 45% females. The gonad histology showed that in the large group, 88% of the eels had immature gonads with ongoing sexual differentiation, 12% were mature with completed sexual differentiation. In the small group, 87% of the eels had immature gonads. The plasma E2 hormone levels were higher in the females of both sizes. In the large group, the average plasma E2 in females was 415 pg/ml, which was significantly higher than the average of 109 pg/ml in males (P < 0.05). In the small group, the average plasma E2 hormone level was 618 pg/ml, which was much higher than the average of 108 pg/ml in males. Quantitative real-time PCR showed that zygote arrest 1 (zar 1) and zona pellucida glycoprotein 3 (zp3) were more highly expressed in females than male. In the H-E staining, an eel in the oil droplet containing ovary stage had a high level of plasma E2 (1500 pg/ml), while an eel with testis in the spermatocyte stage had a low (60 pg/ml). E2 is a potentially useful tool and could play an important role in sex determination in broodstocks.

РАДИОПРОТЕКТОРНЫЙ ЭФФЕКТ ЭРАКОНДА НА СПЕРМАТОГЕНЕЗ ПРИ ВОЗДЕЙСТВИИ ОДНОКРАТНОГО ВНЕШНЕГО ОСТРОГО γ-ОБЛУЧЕНИЯ

Purpose: Experimental evaluation of the radioprotective effect of Erakond on spermatogenesis in BALB/c mice under external acute γ-irradiation. Material and methods: Single external γ-irradiation of males at a dose of 1 Gy was carried out at the IGUR facility (137Cs, dose rate 0.85 Gy/min). Erakond was administered orally for 6 days followed by irradiation 2 weeks later. Violation of spermatogenesis and its correction by eracondas in irradiated animals was assessed by the morphofunctional state of the testes, spermatozoa and the reproductive function of males. Results: In mice on days 16, 24, 48 after irradiation, the number of seminiferous tubules with destructive changes in the spermatogenic epithelium increases from 2.4 to 5.4; 10.2 8.3 % respectively. Erakond contributed to the reduction in the number of seminiferous tubules with destruction to 3.2; 5.1 and 3.5 % respectively. On the 24th, 48th day after irradiation, the number of spermatozoa with an abnormal head increases from 2.8 to 4.8 and 4.5 %; and tail pathology from 4.2 to 8.2 and 7.5 %, respectively, the number of live spermatozoa decreases from 58.1 to 40.5 and 20.0 %, respectively. Erakond contributed to a decrease in the number of spermatozoa with an abnormal head to 3.0; 3.5 %, with tail pathology up to 6.1; 5.3 % and an increase in the number of live sperm up to 50.8; 35.5 % respectively. In mice, on days 16, 24, and 48 after irradiation, the spermatogenea index decreased from 3.4 to 1.5; 0.9 and 2.1, respectively, Erakond contributed to an increase in the spermatogenesis index to 1.9; 2.1 and 2.9 respectively. In mice after irradiation, pre-implantation death at the stages of mature spermatozoa, spermatids, spermatocytes and spermatogonia increased from 24.1 to 41.0; 39.8 and 44.7; 42.0 %, respectively, and post-implantation death at the stages of mature sperm, spermatids, spermatocytes from 16.9; up to 26.5; 27.1 and 38.4 % respectively. The number of live fetuses per female decreased from 5.8 to 3.0; 3.9 and 3.7 respectively. Erakond statistically significantly contributed to the reduction of pre-implantation death at the stages of mature sperm, spermatids, spermatocytes and spermatogonia to 35.6; 33.4; 37.5 and 34.1, respectively, and a decrease in post-implantation death at the stages of mature sperm, spermatids and spermatocytes to 21.6; 20.5 and 28.2 respectively. Conclusion: The data obtained indicate the possible preventive use of Erakond as an effective dietary supplement for the correction of spermatogenesis disorders when exposed to ionizing radiation.

Testicular development, reproducing references and length at first maturity of Acentrogobius viridipunctatus (Actinopteri: Gobiiformes) in the southwest Viet Nam

This study provided knowledge on testicular development, spawning reference and length at first maturity (Lm) of Acentrogobius viridipunctatus—a target catching fish for food supply in the southwest Viet Nam. A total of 528 individuals were collected using trawl nets from January to December 2020 at Long Huu-Tra Vinh (LHTV), Trung Binh-Soc Trang (TBST), Dien Hai-Bac Lieu (DHBL) and Tan Thuan-Ca Mau (TTCM). Five developmental stages of testis were found, and testis diameter increased from ∼1.07 (stage I) to ∼4.82 mm (stage V). Testis stage I consisted of spermatogonia (S) which shifted to primary spermatocytes (SC1) in stage II. In testis stage III, SC1 was divided into secondary spermatocytes (SC2). At this stage, testis consisted of S, SC1, SC2 and some spermatid (ST). At stages IV and V, testis comprised mainly spermatozoa (SZ) besides S, SC1, SC2 and ST, showing that this goby was a multi-spawner. Testis frequency and gonadosomatic index analyses showed that this species released sperms yearly, with a prominent peak in the wet season. The Lm decreased from 9.3 ± 0.3 cm at TBST to 9.0 ± 0.3 cm at LHTV, 8.9 ± 0.2 cm at TTCM and 6.5 ± 0.5 cm at DHBL. Findings provided fundamental data to set up suitable fishing and conserving strategies for this species.

A novel Dmrt gene of crustacean: Functional analysis of idmrt-2 gene in the male reproductive system from Scylla paramamosain

The Dmrt (double-sex and mab-3 related transcription factor) gene family is considered to be a highly conserved gene family related to sex determination and sexual differentiation across species. In order to better understand the role of the idmrt-2 gene in gonad development in Scylla paramamosain, the idmrt-2 gene was cloned and analyzed. The cDNA contains a 1659 bp ORF region encoding 552 amino acids. The qRT-PCR results showed that idmrt-2 was significantly more expressed in the testis than in other tissues (p < 0.05). The expression of idmrt-2 was highest in the spermatids stage (T2 stage), followed by the mature sperms stage (T3 stage) and significantly higher than in the spermatocytes stage (T1 stage) (p < 0.05) during testicular development and the expression difference was not significant in different stages of ovarian development. RNAi studies revealed that after idmrt-2 was knocked down, the expression of Dmrt-like and foxl-2 genes in the testis decreased, as well as IAG expression in the androgenic gland. The findings suggest that idmrt-2 may be an IAG regulator and involved in testicular development.

Hybridization with Percocypris pingi male can improve the cultivation characteristics of snow trout (Schizothorax wangchiachii), especially the resistance to white spot disease (Ichthyophthirius multifiliis)

Snow trout (Schizothorax) is an important cold-water economic fish in Asian aquaculture, but it has some disadvantages, such as slow growth rate, weak resistance to white spot disease (Ichthyophthirius multifiliis) and high temperature, etc. In contrast, their sister genus, Percocypris, has stronger resistance to white spot disease and high temperature. Distant hybridization can integrate the advantages of both parents, so we attempted to cross S. wangchiachii with P. pingi to obtain F1 hybrids combining the advantages of both parents. Hybridization between P. pingi males and S. wangchiachii females was successful, but backcrossing failed. To explore the cultivation characteristics of hybrid fish, the growth performance, digestive enzyme activity, nutrient composition, gonad development, high temperature tolerance, and white spot disease resistance of hybrid fish and their parents were compared. In growth, a total of 18-week culture experiment (20 °C) were carried out, and the body weight of hybrid fish at 18 weeks (26.13 ± 7.34 g) was significantly higher than that of P. pingi (16.65 ± 6.82 g) and S. wangchiachii (16.05 ± 5.93 g). In digestive enzyme activity, the hybrid fish showed hybrid weakness, but there was no correlation between the digestive enzyme activity and body weight of the hybrid fish and its parents, indicating that the digestive enzyme activity could not reflect the growth differences. In nutritional composition, P. pingi had a higher crude protein content, S. wangchiachii had a higher crude lipid content, and both contents of hybrid fish were closer to those of P. ping. The relative contents of amino acids of the three fishes were similar, while the relative contents of polyunsaturated fatty acids were higher in hybrid fish and P. ping, and their relative content of fishy substances was lower than that of S. wangchiachii. In high temperature tolerance, the mortality temperature of P. ping (33.48 ± 0.39 °C) and hybrid fish (33.00 ± 0.92 °C) was significantly higher than that of S. wangchiachii (31.24 ± 1.07 °C). In tolerance to white spot disease, the hybrid fish showed a significant increase in resistance compared to S. wangchiachii and was almost free of I. multifiliis. In gonad development, the spermatic cells of the pentaploid hybrid fish remained in the spermatocyte stage without spermatozoa, their ovarian cells were lowly differentiated, and these characteristics were sterile phenotypes. In conclusion, hybridization with male P. ping can improve the cultivation characteristics of S. wangchiachi through preliminary research, providing a new perspective and reference for snow trout breeding.