OBJECTIVE: To observe the effects of electroacupuncture (EA) with different frequencies on spermatogenic function, testicular morphology and oxidative stress in oligoasthenospermia (OAT) rats, and to explore the mechanism and the optimal parameters of EA for OAT. METHODS: Sixty SPF-grade male SD rats were randomly divided into a solvent control group, a model group, a 2 Hz EA group, a 100 Hz EA group and a 2 Hz/100 Hz EA group, with 12 rats in each group. Except for the solvent control group, the other 4 groups were administered ornidazole suspension (800 mg·kg^-1·d^-1) by gavage for 28 d to establish the OAT model. Starting from the 1st of modeling, EA was applied at "Guanyuan" (CV4), "Qihai" (CV6) and bilateral "Sanyinjiao" (SP6) and "Zusanli" (ST36) in the 3 EA groups, continuous wave of 2 Hz, continuous wave of 100 Hz, and disperse-dense wave of 2 Hz/100 Hz were used in the 2 Hz EA group, the 100 Hz EA group, and the 2 Hz/100 Hz EA group, respectively, with current intensity of 1-3 mA, 30 min a time, once every other day, for 28 consecutive days. After intervention, the testicular index was calculated, epididymal sperm quality was assessed, and the fertility ability was observed; morphology of testicular tissue was observed by HE staining, and the Johnson score was calculated; the positive expression of reactive oxygen species (ROS) in testicular tissue was detected by immunofluorescence; the activity of superoxide dismutase (SOD) and catalase (CAT), as well as the level of malondialdehyde (MDA) in testicular tissue were measured by ELISA; the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in testicular tissue was detected by Western blot. RESULTS: Compared with the solvent control group, in the model group, the testicular index, sperm concentration, sperm motility and the number of offspring were decreased (P<0.01), the seminiferous tubules atrophied and the Johnson score decreased (P<0.01); the activity of SOD and CAT, as well as the protein expression of Nrf2 and HO-1 in testicular tissue were decreased (P<0.01); the sperm deformity rate, the positive expression of ROS and the MDA level in testicular tissue were increased (P<0.01). Compared with the model group, in the 2 Hz EA group, the 100 Hz EA group and the 2 Hz/100 Hz EA group, the testicular index, sperm concentration, sperm motility and the number of offspring were increased (P<0.05, P<0.01), the pathological morphology of testicular tissue improved and the Johnson scores increased (P<0.01); the activity of SOD and CAT, as well as the protein expression of Nrf2 and HO-1 in testicular tissue were increased (P<0.05, P<0.01); the sperm deformity rate, the positive expression of ROS and the MDA level in testicular tissue were decreased (P<0.05, P<0.01). Compared with the 2 Hz EA group, in the 2 Hz/100 Hz EA group, the testicular index, sperm concentration, sperm motility, as well as the CAT activity and HO-1 protein expression in testicular tissue were increased (P<0.01, P<0.05); the positive expression of ROS was decreased (P<0.01). Compared with the 100 Hz EA group, in the 2 Hz/100 Hz EA group, the testicular index was increased (P<0.01), the positive expression of ROS in testicular tissue was decreased (P<0.01). CONCLUSION EA with 2 Hz continuous wave, 100 Hz continuous wave, and 2 Hz/100 Hz disperse-dense wave can all improve the spermatogenic arrest and reduce the level of oxidative stress in testicular tissue in OAT rats, the mechanism may be related to up-regulating the protein expression of Nrf2 and HO-1 and improving oxidative stress. EA with disperse-dense wave of 2 Hz/100 Hz shows the optimal effect.
Male ; Animals ; Electroacupuncture ; Oxidative Stress ; Rats ; Rats, Sprague-Dawley ; Spermatogenesis ; Oligospermia/genetics* ; Humans ; Testis/metabolism* ; Superoxide Dismutase/metabolism* ; Asthenozoospermia/genetics* ; Acupuncture Points ; Malondialdehyde/metabolism*

Recently, male reproductive health has attracted extensive attention, with the adverse effects of circadian disruption on male fertility gradually gaining recognition. However, the mechanism by which circadian disruption leads to damage to male reproductive system remains unclear. In this review, we first summarized the dual regulatory roles of circadian clock genes on the male reproductive system: (1) circadian regulation of testosterone synthesis via the hypothalamic-pituitary-testicular (HPT) and hypothalamic-pituitary-adrenal (HPA) axes; (2) non-circadian regulation of spermatogenesis. Next, we further listed the possible mechanisms by which circadian disruption impairs male fertility, including interference with the oscillatory function of the reproductive system, i.e., synchronization of the HPT axis, crosstalk between the HPT axis and the HPA axis, as well as direct damage to germ cells by disturbing the non-oscillatory function of the reproductive system. Future research using spatiotemporal omics, epigenomic assays, and neural circuit mapping in studying the male reproductive system may provide new clues to systematically unravel the mechanisms by which circadian disruption affects male reproductive system through circadian clock genes.
Male ; Humans ; Animals ; Circadian Clocks/physiology* ; Hypothalamo-Hypophyseal System/physiology* ; Circadian Rhythm/genetics* ; Spermatogenesis/physiology* ; Pituitary-Adrenal System/physiology* ; Testis/physiology* ; Testosterone/biosynthesis* ; CLOCK Proteins ; Infertility, Male/physiopathology*

The genome tagging project (GTP) plays a pivotal role in addressing a critical gap in the understanding of protein functions. Within this framework, we successfully generated a human influenza hemagglutinin-tagged sperm-specific protein 411 (HA-tagged Ssp411) mouse model. This model is instrumental in probing the expression and function of Ssp411. Our research revealed that Ssp411 is expressed in the round spermatids, elongating spermatids, elongated spermatids, and epididymal spermatozoa. The comprehensive examination of the distribution of Ssp411 in these germ cells offers new perspectives on its involvement in spermiogenesis. Nevertheless, rigorous further inquiry is imperative to elucidate the precise mechanistic underpinnings of these functions. Ssp411 is not detectable in metaphase II (MII) oocytes, zygotes, or 2-cell stage embryos, highlighting its intricate role in early embryonic development. These findings not only advance our understanding of the role of Ssp411 in reproductive physiology but also significantly contribute to the overarching goals of the GTP, fostering groundbreaking advancements in the fields of spermiogenesis and reproductive biology.
Animals ; Female ; Humans ; Male ; Mice ; Spermatids/metabolism* ; Spermatogenesis/physiology* ; Spermatozoa/metabolism* ; Thioredoxins/genetics*

Infertility has become one of the most serious diseases worldwide, and 50% of this disease can be attributed to male-related factors. Spermatogenesis, by definition, is a complex process by which spermatogonial stem cells (SSCs) self-renew to maintain stem cell population within the testes and differentiate into mature spermatids. It is of great significance to uncover gene regulation and signaling pathways that are involved in the fate determinations of SSCs with aims to better understand molecular mechanisms underlying human spermatogenesis and identify novel targets for gene therapy of male infertility. Significant achievement has recently been made in demonstrating the signaling molecules and pathways mediating the fate decisions of mammalian SSCs. In this review, we address key gene regulation and crucial signaling transduction pathways in controlling the self-renewal, differentiation, and apoptosis of SSCs, and we illustrate the networks of genes and signaling pathways in SSC fate determinations. We also highlight perspectives and future directions in SSC regulation by genes and their signaling pathways. This review could provide novel insights into the genetic regulation of normal and abnormal spermatogenesis and offer molecular targets to develop new approaches for gene therapy of male infertility.
Humans ; Male ; Signal Transduction/physiology* ; Apoptosis/physiology* ; Spermatogenesis/physiology* ; Cell Differentiation ; Adult Germline Stem Cells/physiology* ; Spermatogonia/cytology* ; Gene Expression Regulation ; Animals ; Infertility, Male/genetics* ; Cell Self Renewal/genetics*

Mouse spermatogenesis entails the maintenance and self-renewal of spermatogonial stem cells (SSCs), which require a complex web-like signaling network transduced by various cytokines. Although brain-derived neurotrophic factor (BDNF) is expressed in Sertoli cells in the testis, and its receptor tropomyosin receptor kinase B (TrkB) is expressed in the spermatogonial population containing SSCs, potential functions of BDNF for spermatogenesis have not been uncovered. Here, we generate BDNF conditional knockout mice and find that BDNF is dispensable for in vivo spermatogenesis and fertility. However, in vitro , we reveal that BDNF -deficient germline stem cells (GSCs) exhibit growth potential not only in the absence of glial cell line-derived neurotrophic factor (GDNF), a master regulator for GSC proliferation, but also in the absence of other factors, including epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and insulin. GSCs grown without these factors are prone to differentiation, yet they maintain expression of promyelocytic leukemia zinc finger ( Plzf ), an undifferentiated spermatogonial marker. Inhibition of phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK), and Src pathways all interfere with the growth of BDNF-deficient GSCs. Thus, our findings suggest a role for BDNF in maintaining the undifferentiated state of spermatogonia, particularly in situations where there is a shortage of growth factors.
Animals ; Male ; Brain-Derived Neurotrophic Factor/genetics* ; Spermatogonia/cytology* ; Mice ; Spermatogenesis/genetics* ; Mice, Knockout ; Cell Differentiation ; Glial Cell Line-Derived Neurotrophic Factor/genetics* ; Promyelocytic Leukemia Zinc Finger Protein/genetics* ; Cell Survival/physiology* ; Signal Transduction/physiology* ; Cell Proliferation/physiology*

Nonobstructive azoospermia (NOA) is a severe and heterogeneous form of male factor infertility caused by dysfunction of spermatogenesis. Although various factors are well defined in the disruption of spermatogenesis, not all aspects due to the heterogeneity of the disorder have been determined yet. In this review, we focus on the recent findings and summarize the current data on epigenetic mechanisms such as DNA methylation and different metabolites produced during methylation and demethylation and various types of small noncoding RNAs involved in the pathogenesis of different groups of NOA.
Humans ; Azoospermia/metabolism* ; Male ; DNA Methylation/genetics* ; Epigenesis, Genetic ; Spermatogenesis/genetics* ; RNA, Small Untranslated/genetics*

Nonobstructive azoospermia (NOA), one of the most severe types of male infertility, etiology often remains unclear in most cases. Therefore, this study aimed to detect four biallelic detrimental variants (0.5%) in the minichromosome maintenance domain containing 2 ( MCMDC2 ) genes in 768 NOA patients by whole-exome sequencing (WES). Hematoxylin and eosin (H&E) demonstrated that MCMDC2 deleterious variants caused meiotic arrest in three patients (c.1360G>T, c.1956G>T, and c.685C>T) and hypospermatogenesis in one patient (c.94G>T), as further confirmed through immunofluorescence (IF) staining. The single-cell RNA sequencing data indicated that MCMDC2 was substantially expressed during spermatogenesis. The variants were confirmed as deleterious and responsible for patient infertility through bioinformatics and in vitro experimental analyses. The results revealed four MCMDC2 variants related to NOA, which contributes to the current perception of the function of MCMDC2 in male fertility and presents new perspectives on the genetic etiology of NOA.
Humans ; Male ; Azoospermia/genetics* ; Meiosis/genetics* ; Spermatogenesis/genetics* ; Adult ; Exome Sequencing ; Microtubule-Associated Proteins/genetics* ; Alleles ; Infertility, Male/genetics*

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by impaired motility of cilia and flagella. Mutations in cilia- and flagella-associated protein 300 ( CFAP300 ) are associated with human PCD and male infertility; however, the underlying pathogenic mechanisms remain poorly understood. In a consanguineous Chinese family, we identified a homozygous CFAP300 loss-of-function variant (c.304delC) in a proband presenting with classical PCD symptoms and severe sperm abnormalities, including dynein arm deficiency and acrosomal malformation, as confirmed by transmission electron microscopy (TEM). Histological analysis revealed multiple morphological abnormalities of the sperm flagella in CFAP300 -mutant individual, whereas immunofluorescence demonstrated markedly reduced CFAP300 expression in the spermatozoa of the proband. Furthermore, tandem mass tag (TMT)-based quantitative proteomics showed that the CFAP300 mutation reduced key spermatogenesis proteins (e.g., sperm flagellar 2 [SPEF2], solute carrier family 25 member 31 [SLC25A31], and A-kinase anchoring protein 3 [AKAP3]) and mitochondrial ATP synthesis factors (e.g., SLC25A31, cation channel sperm-associated 3 [CATSPER3]). It also triggered abnormal increases in autophagy-related proteins and signaling mediator phosphorylation. These molecular alterations are likely to contribute to progressive deterioration of sperm ultrastructure and function. Notably, successful pregnancy was achieved via intracytoplasmic sperm injection (ICSI) using the proband's sperm. Overall, this study expands the known CFAP300 mutational spectrum and offers novel mechanistic insights into its role in spermatogenesis.
Humans ; Male ; Infertility, Male/pathology* ; Acrosome/pathology* ; Sperm Tail/pathology* ; Pedigree ; Spermatozoa ; Adult ; Loss of Function Mutation ; Ciliary Motility Disorders/genetics* ; Spermatogenesis/genetics* ; Female

Male reproductive disorders have emerged as a global issue. Infertility affects 8% to 12% of couples of childbearing age. The sperm concentration and total sperm count of men have shown a significant downward trend over the past four decades, with a decrease of more than 50%. Male reproductive disorders are related to multiple factors. Circular RNA (circRNA) is a type of non-coding RNA with covalently closed circular structures. It is involved in a variety of biological processes, including gene expression regulation, protein function regulation and epigenetic regulation. Studies have shown that there are differences in the expression of circRNA in the testicles and semen between infertile patients and healthy people, suggesting that circRNA is involved in the process of spermatogenesis, and its abnormal expression is associated with male infertility. This review takes the biological functions of circRNA as the starting point and summarizes the research progress of circRNA in male reproductive disorders. CircRNA has the potential to serve as a novel biomarker due to its conservative, special structure and tissue specificity, which provides a new strategy for the clinical diagnosis of male reproductive disorders.
Humans ; Male ; RNA, Circular ; Infertility, Male/genetics* ; RNA/genetics* ; Spermatogenesis

OBJECTIVE: To explore the immunological mechanisms underlying spermatogenetic malfunction in patients with non-obstructive azoospermia (NOA) based on bioinformatics and machine learning, and to screen out the key genes associated with spermatogenesis failure. METHODS: NOA-related datasets were obtained from the GEO database, and the differentially expressed genes identified by differential analysis and weighted gene co-expression network analysis (WGCNA). A model of spermatogenesis scoring was established for analysis of the immunological microenvironment and cell interaction networks related to spermatogenesis failure. The key genes were screened out by machine learning, followed by analysis of their correlation with T cells and macrophages. An NOA mouse model was constructed for validation of transcriptome sequencing. RESULTS: Seventy-five differentially expressed genes were identified for the establishment of the spermatogenesis scoring model. The low spermatogenesis score group showed a higher infiltration of the immune cells, with an increased proportion of T cells and macrophages and a correlation of cell interaction signals with immunity. SOX30, KCTD19, ASRGL1 and DRC7 were identified by machine learning as the key genes related to spermatogenesis, with down-regulated expressions in the NOA group, and their expression levels negatively correlated with the infiltration of T cells and macrophages. The accuracy of the spermatogenesis scoring and machine learning models, as well as the trend of the expression levels of the key genes, was successfully validated with the transcriptome sequencing data on the NOA mouse testis. CONCLUSION The development of NOA is closely associated with enhanced immunological microenvironment in the testis. T cells and macrophages may play important roles in spermatogenesis failure. SOX30, KCTD19, ASRGL1 and DRC7 are potential biomarkers for the diagnosis and treatment of NOA.
Male ; Azoospermia/genetics* ; Machine Learning ; Animals ; Computational Biology ; Mice ; Humans ; Spermatogenesis/genetics* ; Gene Expression Profiling ; Macrophages/immunology* ; Gene Regulatory Networks ; T-Lymphocytes/immunology* ; Transcriptome