Search Results (374)

Many experimental and clinical studies published so far demonstrate that melatonin—produced mainly by the pineal gland located deep in the middle of the brain, between the two cerebral hemispheres, and in smaller quantities in a number of other organs and cells of the body—can be successfully used to treat different types of human female infertility. To accomplish this, melatonin acts mainly on the ovary, the uterus, and the preimplantation embryo, through its antioxidant, anti-inflammatory, and immunomodulatory effects, in addition to acting as a hormone and cytokine modulator. In particular, it increases oocyte developmental competence and uterine receptivity for the implanting embryo, improves placental health and function, prevents immune rejection of the implanting embryo and spontaneous pregnancy loss, and alleviates symptoms of endometriosis and adenomyosis. Yet, the use of melatonin in these contexts remains relatively limited, despite its convincing safety profile. This may be partly due to the fact that pertinent data concerning the use of melatonin in female infertility treatment are dispersed across various specialized scientific and medical journals, making it difficult for doctors and embryologists confronted with female infertility issues to access all of them. Therefore, this article was written to provide data that are easily understood. It draws from recent findings collected from different specialized journals focused on the molecular mechanisms of action, the clinical data, and the safety of this multifaceted biomolecule in the treatment of female infertility. Full article

Extracts of aromatic medicinal plants have been extensively studied regarding their numerous bioactivities. However, despite being highly used by humans, studies on the safety of these extracts for animal use are scarce. In this study, we aim to contribute to the determination of the safety profile of plant extracts by focusing on the reproductive toxicity of hydrolates (a by-product of essential oils production) of four endogenous Portuguese plants—Cistus ladanifer, Cupressus lusitanica, Helychrisium italicum, and Thymbra capitata—by studying their effects on bovine oocytes and spermatozoa. To achieve our aims, we determined the oocyte maturation and viability rate in the bovine in vitro maturation test (bIVM) and the bovine sperm viability using the eosin–nigrosin test, in the presence of five concentrations of each hydrolate at half-log intervals (% v/v of culture media). We found that hydrolates did not affect oocyte maturation or viability (maximum concentration tested: 0.2%, v/v). Regarding the sperm viability test, we found that T. capitata and C. ladanifer hydrolates impaired sperm viability (p < 0.05) (maximum concentration tested: 0.2%, v/v), in comparison with the negative control. In summary, we found that H. italicum and C. lusitanica hydrolates were safe regarding oocyte maturation, oocyte viability, and sperm viability, being candidates to be included in bovine husbandry as feeding additives. Full article

Diverse neuronal nicotinic acetylcholine receptor (nAChR) subtypes are expressed in hippocampal interneurons. Single-cell analysis of mRNA expression previously revealed prominent co-expression of the α3 and β2 subunits within rat interneurons in the CA1 region. Although the α3 subunit (traditionally expressed together with β4) is usually associated with the peripheral nervous system, its significant co-expression with the β2 subunit in hippocampal interneurons suggests a distinct, potentially novel central nervous system nAChR subtype. We demonstrate that the human α3 and β2 subunits injected into Xenopus laevis oocytes can assemble into at least two functionally distinct subtypes of nAChRs based on different subunit stoichiometries. These subtypes exhibit similar reversal potentials but differ significantly in their desensitization kinetics and acetylcholine (ACh) affinities. The response obtained from a 1:5 α3:β2 mRNA injection ratio shows a higher affinity for ACh and significantly greater desensitization during prolonged ACh application compared to the response obtained from a 5:1 α3:β2 mRNA injection ratio. The identification of distinct functional α3β2 subtypes, characterized by differential desensitization kinetics and ACh affinity, could represent novel targets for the potential development of highly selective cognitive therapeutics for conditions such as Alzheimer’s disease, autism spectrum disorder, and attention deficit hyperactivity disorder, where hippocampal nAChRs are implicated. Full article

Oocytes from women of advanced reproductive age exhibit diminished developmental potential, but the underlying mechanisms remain incompletely defined. Oocyte maturation depends on translational control of maternal mRNA synthesized during growth. We performed a computational analysis on human oocytes from women <30 versus ≥40 years and observed that mRNA GC content correlates negatively with half-life in oocytes from young (<30 yr) but positively with oocytes from aged (>40 yr) women. In young oocytes, longer mRNA half-life is associated with lower protein abundance, whereas in aged oocytes GC content correlates positively with protein abundance. During the GV-to-MII transition, codon composition stratifies stability: codons that support rapid translation (optimal) stabilize mRNA, while slow-translating codons (non-optimal) promote decay. With reproductive aging, GC-containing codons become more optimal and align with increased protein abundance. These findings indicate that reproductive aging remodels codon-optimality-linked, translation-coupled mRNA decay, stabilizing a subset of GC-rich maternal mRNA that may be prone to excess translation during maturation. Our analysis is explicitly within human reproductive aging; it does not revisit cross-species stability rules. Instead, it shows that sequence–stability relations are reprogrammed with age within human oocytes, including an inversion of the GC–stability association during GV-to-MII transition. Disruption of the normal mRNA clearance program in aged oocytes may compromise oocyte competence and alter maternal mRNA dosage, with downstream consequences for early embryonic development. Full article

Long non-coding RNAs (lncRNAs) are essential regulatory molecules involved in various biological processes in mammals. However, their expression patterns across multiple porcine tissues have not been systematically characterized. We analyzed 607 RNA-seq datasets derived from 14 porcine tissues, including backfat, gallbladder, heart, ileum, jejunum, kidney, longissimus dorsi, liver, lung, skeletal muscle, ovary, pituitary, skeletal muscle, and spleen. Additionally, we examined 63 single-cell RNA-seq datasets from porcine primary oocytes at five developmental stages. For comparative analysis, we included 20 human and 17 mouse oocyte RNA-seq datasets. We identified 52,798 porcine lncRNAs, with tissue-specific expression patterns most prominent in oocytes and least in skeletal muscle. Among them, 2169 were classified as housekeeping and 14,469 as tissue-specific lncRNAs. Cross-species analysis revealed that a small subset of oocyte-expressed lncRNAs is conserved in humans and mice, associated with catalytic activity and circadian regulation. Additionally, 44 lncRNAs were differentially expressed during oocyte development, implicating them in neurogenesis, vesicle transport, and protein modification. Our findings not only contribute to the growing body of knowledge regarding lncRNAs in porcine biology but also pave the way for future research aimed at elucidating their functional roles in reproductive biology and other physiological processes. Full article

This study evaluated the reproductive toxicity and reversibility of gossypol exposure in female Institute of Cancer Research (ICR) mice using the Targeted Risk Assessment of Environmental Chemicals (TRAEC) framework. Mice treated with gossypol (20 mg/kg/day, 30 days) showed reduced body weight (35.90 ± 3.19 g vs. 30.26 ± 0.91 g, p < 0.001), depletion of primordial follicles (46.2 ± 4.8 vs. 27.5 ± 3.6, p < 0.01), and impaired oocyte maturation, with polar body extrusion decreasing from 65.9% to 22.6% at 60 μM (p < 0.0001). In the human granulosa-like tumor cell line (KGN), apoptosis increased to 91.1% at 20 μg/mL compared with 11.46% in controls (p < 0.0001). Proteomic profiling identified 151 differentially expressed proteins, enriched in steroidogenesis, immune regulation, and mitochondrial metabolism. After one-month withdrawal, partial morphological recovery was observed, but endocrine function remained impaired. The TRAEC risk score of 4.68 classified gossypol as a moderate reproductive toxicant. These findings indicate that gossypol damages ovarian reserve and oocyte competence, with only partial reversibility, highlighting the need for caution in its clinical use. Full article

The number of female astronauts participating in space missions is increasing, and concerns about the impact of spaceflight on reproductive health have emerged. Space radiation and microgravity pose potential threats to ovarian reserve and uterine function, but data on human female reproductive health in space remain scarce. This review explores current evidence from both real and simulated space conditions, including animal studies and ground-based cosmic radiation models. The relevant literature on cosmic radiation, fertility preservation strategies, and gynecological risk management in spaceflight was analyzed to provide a comprehensive synthesis. Space radiation might damage ovarian follicles and impair folliculogenesis, potentially leading to premature ovarian failure and microgravity might alter endocrine function. While human data are lacking, murine and in vitro model studies suggest significant reproductive risks. Embryo/oocyte and ovarian tissue cryopreservation are currently the most viable fertility preservation strategies. Shielding technologies, radioprotective agents, and hormonal modulation may offer adjunct protection. In conclusions, fertility counseling and preservation should become integral to pre-mission planning for female astronauts of reproductive age. A personalized approach, accounting for individual reproductive goals, age and mission duration, is essential. Further research is urgently needed to understand the reproductive effects of deep space travel and to develop targeted protective strategies. Full article

The capability to generate induced pluripotent stem cells (iPSCs) from adult somatic cells, enabling them to differentiate into any cell type, has been demonstrated in several studies. In humans and mice, iPSCs have been shown to differentiate into primordial germ cells (PGCs), spermatozoa, and oocytes. However, research on iPSCs in deer is novel. Despite the necessity for establishing germplasm banks from endangered cervid species, the collection and cryopreservation of gametes and embryos have proven complex for this group. Therefore, the focus of this study was to establish protocols for deriving stable iPSC lines from Blastocerus dichotomus (Marsh deer) using primary cells derived from antler, adipose tissue, or skin, with the ultimate goal of producing viable gametes in the future. To achieve this, two main reprogramming approaches were tested: (1) transfection using PiggyBac transposons (plasmid PB-TET-MKOS) delivered via electroporation and (2) lentiviral transduction using the STEMCCA system with either human (hOSKM) or murine (mOSKM) reprogramming factors. Both systems utilized murine embryonic fibroblasts (MEFs) as feeder cells. The PiggyBac system was further supplemented with a culture medium containing small molecules to aid reprogramming, including a GSK inhibitor, MEK inhibitor, ALK/TGF inhibitor, and thiazovivin. Initial colony formation was observed; however, these colonies failed to expand post-selection. Despite these challenges, important insights were gained that will inform and guide future studies toward the successful generation of iPSCs in deer. Full article

Ovarian aging is characterized by a gradual decline in both reproductive and endocrine functions, ultimately culminating in the cessation of ovarian activity around the age of 50, when most women experience natural menopause. The decline begins early, as follicular attrition is initiated in utero and continues throughout childhood and reproductive life. Most follicles undergo atresia without progressing through substantial stages of growth. With increasing age, a pronounced reduction occurs in the population of resting follicles within the ovarian reserve, accompanied by a decline in the size of growing follicular cohorts. Around the age of 38, the rate of follicular depletion accelerates, sometimes resulting in diminished ovarian reserve (DOR). The subsequent menopausal transition involves complex, irregular hormonal dynamics, manifesting as increasingly erratic menstrual patterns, primarily driven by fluctuations in circulating estrogens and a rising incidence of anovulatory cycles. In parallel with the progressive depletion of the follicular pool, the serum concentrations of anti-Müllerian hormone (AMH) decline gradually, while reductions in inhibin B levels become more apparent during the late reproductive years. The concomitant decline in both inhibin B and estrogen levels leads to a compensatory rise in circulating follicle-stimulating hormone (FSH) concentrations. Together, these endocrine changes, alongside the eventual exhaustion of the follicular reserve, converge in the onset of menopause, which is defined by the absence of menstruation for twelve consecutive months. The mechanisms contributing to ovarian aging are complex and multifactorial, involving both the oocyte and the somatic cells within the follicular microenvironment. Oxidative stress is thought to play a central role in the age-related decline in oocyte quality, primarily through its harmful effects on mitochondrial DNA integrity and broader aspects of cellular function. Although granulosa cells appear to be relatively more resilient, they are not exempt from age-associated damage, which may impair their hormonal activity and, given their close functional relationship with the oocyte, negatively influence oocyte competence. In addition, histological changes in the ovarian stroma, such as fibrosis and heightened inflammatory responses, are believed to further contribute to the progressive deterioration of ovarian function. A deeper understanding of the biological processes driving ovarian aging has facilitated the development of experimental interventions aimed at extending ovarian functionality. Among these are the autologous transfer of mitochondria and stem cell-based therapies, including the use of exosome-producing cells. Additional approaches involve targeting longevity pathways, such as those modulated by caloric restriction, or employing pharmacological agents with geroprotective properties. While these strategies are supported by compelling experimental data, robust clinical evidence in humans remains limited. Full article

Background/Objectives: Platelet-derived growth factor receptor alpha (PDGFRα) is a receptor involved in cell growth and differentiation, with unclear roles in ovarian tissues and potential interactions with KCNK3 (potassium two-pore domain channel subfamily K member 3), a member of the two-pore domain K⁺ channel involved in cellular homeostasis. This study aims to map PDGFRα expression across mouse tissues and to explore its co-expression with KCNK3 in the ovary. Methods: We visualized PDGFRα expression using RNA-seq data from the genotype-tissue expression (GTEx) BodyMAP across 54 human tissues and Cap Analysis of Gene Expression (CAGE) data for various mouse tissues. In PDGFRα^EGFP mice expressing EGFP in PDGFRα⁺ cells, histological and fluorescence imaging were used to assess ovarian expression. Immunohistochemistry determined the co-localization of PDGFRα and KCNK3, and qPCR quantified their mRNA levels in the ovary, oviduct, and uterus. Results: PDGFRα showed high expression in human and mouse female reproductive tissues, particularly the ovary. In the PDGFRα^EGFP mouse model, PDGFRα was primarily found in the thecal layer and stromal cells, not in granulosa cells or oocytes. Immunohistochemistry indicated that 90.2 ± 8.7% of PDGFRα⁺ cells expressed KCNK3 in the ovarian stroma. qPCR revealed lower PDGFRα and KCNK3 expression in the ovary compared to the oviduct and uterus. Conclusions: This study shows that PDGFRα is predominantly expressed in ovarian stromal and theca cells and is highly co-localized with KCNK3, suggesting a potential role for PDGFRα⁺ cells in ionic regulation and their possible involvement in follicular development and ovarian physiology. Full article

Sperm count, motility, and morphology are semen parameters that directly affect male fertility. The presence of cytokines in seminal plasma negatively or positively influences these parameters. Interleukins and prostaglandins are proinflammatory cytokines present in human seminal plasma and play crucial roles in fertilization, in general and after intracytoplasmic sperm injection (ICSI) procedures. This study aimed to investigate the possible influence of interleukins IL-17 and IL-18, and prostaglandins PGE2 and PGF2α on male infertility. Semen samples were collected from 58 males who underwent the ICSI procedure. An enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of IL-17, IL-18, PGE2, and PGF2α, and these concentrations were then correlated with semen parameters and the rate of fertilization. Furthermore, the chromatin integrity of the sperm was evaluated with an Acridine Orange (AO) assay. The results showed an inversely proportional relationship between the AO binding intensity and fertilization rate (r = −0.394; p ≤ 0.002). Furthermore, a negative correlation was observed between the IL-18 concentration and positive AO (p ≤ 0.021). Moreover, the IL-18 concentration was positively correlated with the fertilization rate (p ≤ 0.05). In contrast, IL-17 did not significantly correlate with any semen parameters or with the fertilization rate. Seminal PGE2 levels were significantly correlated with embryo cleavage at 72 h (p ≤ 0.05). To conclude, this study revealed that denaturation of sperm nuclear deoxyribonucleic acid (DNA) contributes to low fertilization rates. In addition, this study proposed a potential role for IL-18 in fertilization. PGE2 likely influences embryo development, but further studies are needed to examine the impact of seminal PGE2 on the oocyte to fully elucidate its contribution to this complex biological process. Full article

Polystyrene microplastics (PS-MPs) released in the environment reportedly affect the reproduction of various organisms, induced oxidative stress and apoptosis, resulting in altered sperm parameters. In this in vitro study, we tested the cytotoxicity and genotoxicity of PS-MPs by exposing human semen samples to PS-MPs levels (105 and 210 μg/mL) for 30–60–90 min. Semen parameters, genome stability, sperm DNA fragmentation (SDF) and reactive oxygen species (ROS) production were analyzed before and after exposure. Moreover, we also evaluated the expression level of spermatozoa-specific expressed genes essential for the fusion with oocyte (DCST1, DCST2, IZUMO1, SPACA6, SOF1, and TMEM95). After PS-MP exposure, semen concentration and morphology did not differ, while sperm vitality and motility decreased in a time-dependent manner. In addition, sperm agglutination was observed in the groups exposed to both PS-MPs concentrations tested. A time- and concentration-dependent reduction in genomic stability, as well as increased SDF and ROS production, was also observed. Moreover, all investigated transcripts were down-regulated after PS-MP exposure. Our results confirm the oxidative stress-mediated genotoxicity and cytotoxicity of PS-MPs on human spermatozoa. The sperm agglutination observed after treatment could be due to the aggregation of PS-MPs already adhered to the sperm membranes, hindering sperm movement and fertilizing capability. Interestingly, the downregulation of genes required for sperm–oocyte fusion, resulting from data on the in vitro experimental system, suggests that PS-MP exposure may have implications for sperm functionality. While these findings highlight potential mechanisms of sperm dysfunction, further investigations using in vivo models are needed to determine their broader biological implications. Possible environmental and working exposure to pollutants should be considered during the counselling for male infertility. Full article

Oocytes and cumulus cells undergo meiotic resumption and proliferation via gonadotropins and growth factors during maturation, and various small G proteins are activated when COCs undergo physiological changes. This study investigated the influence of gonadotropins and growth factors on Ras and its GTPases during porcine COC maturation. Unmatured COCs were treated with FSH, LH, or EGF for 44 h. The mRNA expression levels of the Ras subfamily (H-Ras, K-Ras, N-Ras, and R-Ras), its GTPases (RASA1 and SOS1), and proliferation factors (ERK, CCNB1, and Cdc2) were analyzed using RT-PCR. In contrast to other Ras subfamilies, R-Ras expression is upregulated during COC maturation. We evaluated the effects of FSH, LH, and EGF at various concentrations that most effectively regulated the expression of R-Ras and GTPases. The results demonstrated that 0.5 µg/mL FSH, 10 IU/mL human chorionic gonadotropin (hCG), and 10 ng/mL EGF effectively enhanced R-Ras expression and cell proliferation. FSH supplementation during porcine COC maturation significantly upregulated R-Ras and ERK expression, independent of LH and EGF, and downregulated Cdc2 expression. These results indicated that FSH regulates R-Ras expression, thereby promoting cell proliferation during COC maturation. These results provide fundamental knowledge for understanding the role of Ras and its family members in the development of follicular environments in pigs. Full article

Per- and polyfluoroalkyl substances (PFASs) comprise a diverse array of synthetic chemicals that resist environmental degradation. They are increasingly recognised as endocrine-disrupting compounds (EDCs). These chemicals, found in non-stick cookware, food packaging, and industrial waste, accumulate in human tissues and fluids, raising substantial concerns regarding their impact on female reproductive health. Epidemiological studies have demonstrated associations between PFAS exposure and reduced fertility; nevertheless, the underlying molecular pathways remain inadequately understood. This narrative review investigates the multifaceted effects of PFASs on ovarian physiology, including its disruption of the hypothalamic–pituitary–ovarian (HPO) axis, alteration of anti-Müllerian hormone (AMH) levels, folliculogenesis, and gonadotropin receptor signalling. Significant attention is directed towards the emerging association between PFASs and polycystic ovarian syndrome (PCOS), wherein PFAS-induced hormonal disruption may exacerbate metabolic issues and elevated androgen levels. Furthermore, we analyse the current data regarding PFAS exposure in women undergoing treatment based on assisted reproductive technologies (ARTs), specifically in vitro fertilisation (IVF), highlighting possible associations with diminished oocyte quality, suboptimal embryo development, and implantation failure. We examine potential epigenetic and transgenerational alterations that may influence women’s reproductive capabilities over time. This study underscores the urgent need for further research and regulatory actions to tackle PFAS-related reproductive toxicity, particularly in vulnerable populations, such as women of reproductive age and those receiving fertility treatments. Full article

The aims of the present study were to analyze the taxonomic profile and to evaluate the functional effects of sheep FF cultivable microbiota on prepubertal lamb oocytes PLOs developmental potential. Ovarian FFs were recovered from slaughtered adult sheep via the aspiration of developing follicles and used for microbiota propagation. Bacterial pellets underwent 16S rRNA gene sequencing and targeted culturomics, whereas cell-free supernatants were used as supplements for the in vitro maturation (IVM) of slaughtered PLOs. For the first time, bacteria presence in adult sheep FF was detected, with the first report of Streptococcus infantarius subsp. infantarius (as a species) and Burkholderia cepacia (as a genus and species) in either animal or human FF. The short- and long-term effects of bacterial metabolites on PLO maturation and embryonic development were demonstrated. As short-term effects, the addition of FF microbiota metabolites did not affect the oocyte nuclear maturation and mitochondria distribution pattern, except in one of the examined supernatants, which reduced all quantitative bioenergetic/oxidative parameters. As long-term effects, one of them reduced the total cleavage rate after in vitro embryo culture (IVC). In conclusion, microbiota/bacteria are present in adult sheep FF and may influence reproductive outcomes in vitro. Future studies may reveal the beneficial in vitro effects using the microbiome from preovulatory follicles. Full article