OBJECTIVE: To observe the effects of the "Zhibian" (BL54)-toward-"Shuidao" (ST28) acupuncture on key regulatory factors during mitochondrial apoptosis of testicular tissue in asthenozoospermia mice, and explore the potential mechanism of the protective effect of acupuncture on reproductive function. METHODS: Thirty C57BL/6 male mice were randomly divided into a blank group, a model group and an acupuncture group, 10 mice in each group. In the model and the acupuncture groups, the intraperitoneal injection of cyclophosphamide (30 mg•kg^-1•d^-1) was delivered for 7 days to prepare the asthenozoospermia model. After the success of modeling, the modeled mice in the acupuncture group were intervened with "Zhibian" (BL54)-toward-"Shuidao" (ST28) acupuncture, once daily and the needles were retained for 20 min. The duration of the intervention was 2 weeks. The general condition of each mouse was observed, and the body mass was recorded before modeling, after modeling and after intervention completion. After intervention, the testicular mass was recorded and the weight coefficient was calculated, and the mouse sperm quality was examined; the serum contents of testosterone (T), follicle stimulating hormone (FSH) and luteinizing hormone (LH) were detected using ELISA, the morphology of testicular tissue was observed using HE, the mitochondrial ultra-microstructure of testicular tissue was observed under transmission electrone microscopy, the mitochondrial membrane potential level of testicular tissue was detected using JC-1 staining, the positive rate of apoptosis cell of testicular tissue was observed using TUNEL; and the mRNA and protein expression of b-cell lymphocytoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), cytochrome c (Cyt C), apoptotic protease-activating factor1 (Apaf-1), Caspase-9 and Caspase-3 of testicular tissue was detected using real-time quantitative fluorescence PCR and Western blot methods separately; and the positive expression of Cleaved Caspase-3 of the testicular tissue was detected using immunohistochemistry. RESULTS: Compared with the blank group, the mice were in listless spirits, had shaggy hairs, the reduced appetite and movement, and weight loss in the model group (P<0.01); the testicular mass and the weight coefficient decreased (P<0.01); the total number of sperms, sperm motility, and sperm viability were declined (P<0.01); while the levels of serum T, FSH, and LH were dropped (P<0.01). The morphology of seminiferous tubules in testicular tissue was abnormal, the number of spermatogenic cells and the number of mitochondria decreased, the inner mitochondrial crest was fractured and lost, and vacuoles appeared. The level of mitochondrial membrane potential was reduced (P<0.01); and the positive rate of apoptosis cell in testicular tissue increased (P<0.01). The mRNA and protein expression of Bax, Cyt C, Apaf-1, Caspase-9 and Caspase-3 was elevated (P<0.01, P<0.05), the mRNA and protein expression of Bcl-2 was dropped (P<0.01), and the average absorbance value of Cleaved Caspase-3 increased (P<0.01). When compared with the model group, in the acupuncture group, the general condition of mice was improved, the testicular mass and the weight coefficient elevated (P<0.01); the total number of sperms, sperm motility, and sperm viability increased (P<0.01); while the levels of serum T, FSH, and LH rose (P<0.01). The pathological morphology of testicular tissue and the inner mitochondrial ultra-microstructure were ameliorated, the level of mitochondrial membrane potential was elevated (P<0.01); the positive rate of apoptosis cell was reduced (P<0.01). The mRNA and protein expression of Bax, Cyt C, Apaf-1, Caspase-9 and Caspase-3 was dropped (P<0.01, P<0.05), the mRNA and protein expression of Bcl-2 elevated (P<0.05), and the average absorbance value of Cleaved Caspase-3 declined (P<0.01). CONCLUSION "Zhibian" (BL54)-toward- "Shuidao" (ST28) acupuncture may ameliorate mouse reproductive function by inhibiting mitochondrial apoptosis pathway, alleviating testicular tissue damage in the asthenospermia mice induced by cyclophosphamide.
Animals ; Male ; Mice ; Apoptosis ; Acupuncture Therapy ; Mitochondria/metabolism* ; Asthenozoospermia/genetics* ; Humans ; Testis/metabolism* ; Mice, Inbred C57BL ; Spermatozoa/metabolism* ; Acupuncture Points ; Sperm Motility ; Testosterone/blood* ; Proto-Oncogene Proteins c-bcl-2/genetics* ; Caspase 3/genetics* ; Follicle Stimulating Hormone/blood* ; Reproduction ; Cytochromes c/genetics* ; bcl-2-Associated X Protein/genetics* ; Apoptotic Protease-Activating Factor 1/genetics*

The production of high-quality oocytes requires precisely orchestrated intercellular communication. Extracellular vesicles (EVs) are cell-derived nanoparticles that play a vital role in the transfer of bioactive molecules, which has gained much attention in the field of diagnosis and treatment. Over the past ten years, the participation of EVs in the reproductive processes of oocytes has been broadly studied and has shown great potential for elucidating the intricacies of female reproductive health. This review provides an extensive discussion of the influence of EVs on oocytes, emphasizing their involvement in normal physiology and altered cargo under pathological conditions. In addition, the positive impact of therapeutic EVs on oocyte quality and their role in alleviating ovarian pathological conditions are summarized.
Humans ; Extracellular Vesicles/physiology* ; Oocytes/cytology* ; Female ; Animals ; Cell Communication/physiology*

Mitochondria serve as multifunctional powerhouses within cells, coordinating essential biological activities that are critical for cell viability, including material metabolism, signal transduction, and the maintenance of homeostasis. They support cells in adapting to complex and fluctuating environments. Oocytes, being the largest cells in multicellular organisms, contain a high number of mitochondria with unique structural characteristics. Mitochondria play active roles in the development and maturation of oocytes. A decline in mitochondrial function negatively affects both the quality and quantity of oocytes, thereby contributing to ovarian aging. However, the specific mechanisms through which mitochondrial dysfunction influences the progression of ovarian aging and impacts reproductive longevity remain unclear. Furthermore, medical strategies aimed at rejuvenating mitochondria to restore ovarian reserve and improve female reproductive potential may open new avenues for clinical treatment. In this review, we summarize the current understanding and key evidence regarding the role of mitochondrial dysfunction in ovarian aging and present emerging medical approaches targeting mitochondria to alleviate premature ovarian aging and enhance reproductive performance.
Humans ; Female ; Mitochondria/physiology* ; Ovary/physiology* ; Aging/physiology* ; Animals ; Oocytes/metabolism*

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*

Depression currently affects about 280 million people worldwide and its prevalence has been increasing dramatically, especially among the young and people of reproductive age, which consequently leads to an increase in antidepressant consumption. Antidepressants are associated with sexual dysfunction in both men and women; however, their role in male fertility has been scarcely studied. Fluoxetine and sertraline, two serotonin reuptake inhibitors (SSRIs), are among the most prescribed antidepressants worldwide. To determine their possible effects, human sperm cells were exposed to either sertraline or fluoxetine at concentrations previously found in blood and seminal fluid of patients undergoing treatment. Spermatozoa were incubated for up to 24 h at 37°C and 5% CO 2 , and important functional parameters such as sperm motility, viability, mitochondrial membrane potential, cellular reactive oxygen species (ROS) production, chromatin/DNA integrity, acrosome status, and tyrosine phosphorylation were assessed. At low levels, fluoxetine consistently decreased progressive motility throughout time while promoting fluctuations in ROS levels and sperm capacitation. Nevertheless, it did not affect viability, mitochondrial membrane potential, acrosome reaction nor chromatin/DNA integrity. Sertraline, on the other hand, had little to nonsignificant impact at low doses, but affected almost all tested parameters at supratherapeutic concentrations. Altogether, our results suggest that both antidepressants may impair sperm function, possibly through different mechanisms of action, but fluoxetine is the only exhibiting mild negative effects at doses found in vivo .
Humans ; Male ; Spermatozoa/drug effects* ; Fluoxetine/pharmacology* ; Sperm Motility/drug effects* ; Sertraline/pharmacology* ; Reactive Oxygen Species/metabolism* ; Antidepressive Agents/pharmacology* ; Membrane Potential, Mitochondrial/drug effects* ; Sperm Capacitation/drug effects* ; Selective Serotonin Reuptake Inhibitors/pharmacology* ; Cell Survival/drug effects* ; Acrosome Reaction/drug effects*

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*

Spermatozoa have a highly complex RNA profile. Several of these transcripts are suggested as biomarkers for male infertility and contribute to early development. To analyze the differences between sperm RNA quantity and expression of protamine ( PRM1 and PRM2 ) and testis-specific histone 2B ( TH2B ) genes, spermatozoa from 33 patients who enrolled in assisted reproduction treatment (ART) program were analyzed. Sperm RNA of teratozoospermic (T), oligoteratozoospermic (OT), and normozoospermic (N) samples was extracted, and the differences in transcript levels among the study groups were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). The correlations of total RNA per spermatozoon and the expression of the transcripts were evaluated in relation to sperm characteristics and preimplantation embryo development. The mean (±standard deviation) RNA amount per spermatozoon was 28.48 (±23.03) femtogram in the overall group and was significantly higher in the OT group than that in N and T groups. Total sperm RNA and gene expression of PRM1 and PRM2 genes were related to preimplantation embryo development and developmental arrest. Specific sperm characteristics were correlated with the expressions of PRM1 , PRM2 , or TH2B genes. We conclude that the sperm RNA amount and composition are important factors and might influence early embryonic development and also differ in different cases of male infertility.
Male ; Humans ; Protamines/metabolism* ; Spermatozoa/metabolism* ; Embryonic Development/genetics* ; Adult ; RNA/genetics* ; Histones/genetics* ; Infertility, Male/genetics* ; Teratozoospermia/genetics* ; Oligospermia/genetics*

According to the World Health Organization (WHO) manual, sperm concentration should be measured using an improved Neubauer hemocytometer, while sperm motility should be measured by manual assessment. However, in China, thousands of laboratories do not use the improved Neubauer hemocytometer or method; instead, the Makler counting chamber is one of the most widely used chambers. To study sources of error that could impact the measurement of the apparent concentration and motility of sperm using the Makler counting chamber and to verify its accuracy for clinical application, 67 semen samples from patients attending the Department of Andrology, West China Second University Hospital, Sichuan University (Chengdu, China) between 13 September 2023 and 27 September 2023, were included. Compared with applying the cover glass immediately, delaying the application of the cover glass for 5 s, 10 s, and 30 s resulted in average increases in the sperm concentration of 30.3%, 74.1%, and 107.5%, respectively (all P < 0.0001) and in the progressive motility (PR) of 17.7%, 30.8%, and 39.6%, respectively (all P < 0.0001). However, when the semen specimens were fixed with formaldehyde, a delay in the application of the cover glass for 5 s, 10 s, and 30 s resulted in an average increase in the sperm concentration of 6.7%, 10.8%, and 14.6%, respectively, compared with immediate application of the cover glass. The accumulation of motile sperm due to delays in the application of the cover glass is a significant source of error with the Makler counting chamber and should be avoided.
Humans ; Male ; Sperm Motility/physiology* ; Sperm Count ; Semen Analysis/methods* ; Spermatozoa/physiology* ; Time Factors

Azoospermia is characterized by the absence of sperm in the ejaculate and is categorized into obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). For men with NOA, testicular sperm extraction (TESE) is the only method to obtain sperm for assisted reproductive technology (ART). Given the rarity of these sperm and the unpredictable success of subsequent retrieval attempts, cryopreservation of microdissection-TESE-obtained sperm is essential. Effective cryopreservation prevents the need for repeated surgical procedures and supports future ART attempts. After first delving into the physiological and molecular aspects of sperm cryopreservation, this review aims to examine the current methods and devices for preserving small numbers of sperm. It presents conventional freezing and vitrification techniques, evaluating their respective strengths and limitations in effectively preserving rare sperm, and compares the efficacy of using fresh versus cryopreserved testicular sperm.
Humans ; Cryopreservation/methods* ; Male ; Sperm Retrieval ; Azoospermia/therapy* ; Semen Preservation/methods* ; Spermatozoa ; Vitrification