Search Results (863)

(1) Background: This study aims to systematically identify key candidate genes and the regulatory networks governing ovarian development in sheep breeds with divergent fecundity. Focusing on elucidating the central regulatory roles of these factors during distinct ovarian developmental stages in highly prolific breeds, the research seeks to reveal the mechanism by which multilevel regulatory networks synergistically determine ewe reproductive capacity. (2) Methods: This study utilized the ovaries from the low-fecundity sheep breed Ujumqin sheep, the high-fecundity breed small-tailed Han sheep, and various developmental stages of small-tailed Han sheep as research subjects. Through whole-transcriptome sequencing analysis, differentially expressed mRNAs(DEGs) and non-coding RNAs (ncRNAs) were screened, and a ceRNA regulatory network was constructed and subjected to bioinformatic analysis. The dual-luciferase reporter gene detection system was employed to validate the targeting relationships within the obtained key circRNA-miRNA-mRNA networks. Finally, qRT-PCR was used to verify the accuracy of the sequencing results. (3) Results: Our analysis constructed two distinct ceRNA networks: one from different fecundity groups (116 DECs, 46 DEMs, 82 DEGs) and another from different ovarian stages (186 DECs, 143 DEMs, 338 DEGs). Functional enrichment revealed key reproduction-related pathways, including Mitogen-Activated Protein Kinase(MAPK), Janus Kinase-Signal Transducer and Activator of Transcription(JAK-STAT), and WNT signaling in the fecundity comparison, and MAPK, Ras, WNT, Hippo signaling in the developmental stage comparison. Integrated analysis identified a core circRNA-miRNA-mRNA network, pinpointing circRNA2058-miR-9226-5p-MET as a central regulatory axis. The dual-luciferase assay confirmed that circRNA2058 acts as a sponge for miR-9226-5p, thereby mediating MET expression. qRT-PCR validation of randomly selected RNAs confirmed the sequencing reliability. (4) Conclusions: this study deciphers a synergistic regulatory network and identifies, for the first time, the pivotal circRNA2058-miR-9226-5p-MET ceRNA axis as an potential critical molecular switch driving follicular dominance in sheep. This discovery provides a molecular foundation for targeting core regulators of ovine reproductive efficiency and offers significant insights for innovative strategies in enhancing sheep reproduction. Full article

The ovarian corpus luteum has functional mechanisms for formation and regression in the reproductive endocrine system. The main functional events of the corpus luteum are angiogenesis and apoptosis mechanisms. The development of the corpus luteum involves homogeneous physiological mechanisms, including cellular functions and reproductive hormones. Angiogenesis is controlled by pro-angiogenic and anti-angiogenic factors. The microenvironment involves various signaling molecules and pathways that may play a potential role in angiogenic response during corpus luteum growth. In luteolysis, the corpus luteum undergoes degeneration, notably induced by reproductive hormones that promote programmed cell death in luteal cells through the apoptosis mechanism. In this sudy, we discuss the mechanisms and functional roles of angiogenesis and apoptosis in the endocrine microenvironment during corpus luteum formation and regression, based on the interrelationship of physiological events in the ovary. Full article

The kodkod (Leopardus guigna) is a vulnerable wild felid native to South America whose population is steadily declining. ARTs offer valuable tools for the preservation of its genetic diversity. Our study provides the first evaluation of the morphological and functional acquisition of competence in kodkod oocytes using protocols previously established for domestic cat oocytes. In total, 29 iCOCs were obtained from the ovaries of a single juvenile female kodkod that deceased in a wildlife rehabilitation center. Based on morphological criteria, 13 oocytes were selected for IVM and subsequently evaluated for developmental competence following parthenogenetic activation (PA) and in vitro culture (IVC). Kodkod oocytes appear to be smaller and have a thinner zona pellucida compared to those of domestic cat oocytes. These kodkod oocytes demonstrated the ability to mature in vitro, underwent cleavage, and developed in vitro to the blastocyst stage by day 9. Here, we show that protocols to manage domestic cat oocytes and embryos can support kodkod in vitro oocyte maturation, activation, and in vitro embryo development. However, given that the results were obtained from a single individual and the protocols were tested in a limited number of oocytes, further studies involving additional specimens are essential to validate these observations and refine ART applications for kodkod conservation. Full article

Polycystic ovary syndrome (PCOS) represents one of the most prevalent endocrine–metabolic disorder in women of reproductive age, which includes but not restricted to reproductive disruptions, insulin resistance (IR), hyperandrogenism, and chronic low-grade inflammation. Its heterogeneous pathophysiology arises from the interplay of metabolic, endocrine, and immune factors, including dysregulated adipokine secretion, cytokine-mediated inflammation, oxidative stress (OS), and mitochondrial dysfunction. Current pharmacological therapies, such as metformin, clomiphene, and oral contraceptives, often provide partial benefits and are limited by side effects, necessitating the exploration of safer, multi-target strategies. Flavonoids, a structurally diverse class of plant-derived polyphenols, have gained attention as promising therapeutic candidates in PCOS due to their antioxidant, anti-inflammatory, insulin-sensitizing, and hormone-modulating properties. Preclinical studies in rodent PCOS models consistently demonstrate improvements in insulin sensitivity, normalization of ovarian morphology, restoration of ovulation, and reduction in hyperandrogenism. Human clinical studies, though limited in scale and heterogeneity, report favorable effects of flavonoids such as quercetin, isoflavones, and catechins on glucose metabolism, adipokine balance, inflammatory markers, and reproductive functions. This evidence-based study critically synthesizes mechanistic insights into how flavonoids modulate insulin signaling, adipokine–cytokine crosstalk, OS, and androgen excess, while highlighting translational evidence and emerging delivery systems aimed at overcoming bioavailability barriers. Collectively, flavonoids represent a promising class of nutraceuticals and adjuncts to conventional therapies, offering an integrative strategy for the management of PCOS. Full article

Background: Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility. The apoptosis of granulosa cells (GCs) is strongly associated with the impaired follicular development in PCOS. The underlying mechanisms, however, remain incompletely elucidated. A significant increase in circulating lactic acid, an anaerobic respiration product, has been detected in PCOS patients. Yet, alterations in local ovarian lactic acid levels and their impact on GCs remain unknown. Methods: PCOS mouse models were established via 20-day daily subcutaneous dehydroepiandrosterone (DHEA) injections. In vitro experiments utilized DHEA-treated KGN cells to mimic hyperandrogenic conditions. Circulating, ovarian, and cellular lactic acid concentrations were quantified. Intracellular and extracellular pH values were measured using BCECF-AM fluorescent probe and a blood gas analyzer, respectively. Apoptosis was assessed through both flow cytometry and TUNEL assay. The antioxidant N-acetylcysteine (NAC) was used to investigate its effects on lactic acid levels and the subsequent GC apoptosis. Results: High androgen levels caused mitochondrial damage, promoted anaerobic glycolysis and led to lactic acid accumulation, inducing decreased intracellular pH and thus apoptosis of GCs. The antioxidant NAC effectively alleviated oxidative stress, mitigated mitochondrial damage, and decreased lactic acid levels and apoptosis in KGN cells. In PCOS mice, NAC improved ovarian morphology, but it did not affect the estrous cycle of the mice. Conclusions: Hyperandrogenemia-induced mitochondrial dysfunction caused the accumulation of lactic acid and thus apoptosis of ovarian GCs in PCOS mice. NAC enhanced mitochondrial function, consequently decreasing lactic acid concentrations. These findings suggest novel therapeutic targets for PCOS. Full article

Cryopreservation and transplantation of intact ovaries offer a promising approach to fertility restoration in cancer patients. However, ischemia–reperfusion injury following transplantation significantly impairs graft function. This study aimed to evaluate the protective effects of melatonin and elucidate its underlying mechanisms of action, including antioxidant and anti-inflammatory properties. Intact ovaries from 8 to 12-week-old LEWIS rats were cryopreserved and subsequently transplanted. Melatonin (25 mg/kg and 50 mg/kg) was administered daily from day 1 to day 4 postoperatively. Estrous cycle recovery and ovarian histology were examined, along with measurements of hormone concentrations, antioxidant activity, and inflammatory mediators. The oxidative stress response, particularly the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response elements (ARE) signaling pathway—including Nrf2, Kelch-like ECH-associated protein 1 (Keap1), and sMafg—was investigated to elucidate melatonin’s protective mechanisms. The roles of melatonin receptors and Nrf2 were investigated using specific receptor antagonists (Luzindole, 4P-PDOT) and an inhibitor (ML385) to confirm the involvement of the MT1/Nrf2/ARE pathway. As a result, rats treated with high-dose melatonin (50 mg/kg) exhibited accelerated estrous cycle recovery, reduced follicular loss, improved serum hormone levels, enhanced antioxidant capacity in serum and ovarian tissue, and decreased levels of inflammatory cytokines. Furthermore, melatonin exerted its antioxidant and anti-inflammatory effects through activation of the Nrf2/ARE signaling pathway via the MT1 receptor. These protective effects were abolished by the inhibition of either Nrf2 or MT1 receptor. In conclusion, these findings demonstrate that melatonin mitigates oxidative stress and inflammatory damage in intact transplanted ovaries through the MT1/Nrf2/ARE signaling axis, thereby preserving ovarian function post-transplantation. Full article

Infertility remains a major global health concern, with diminished ovarian reserve (DOR), premature ovarian insufficiency (POI), polycystic ovary syndrome (PCOS), and impaired endometrial receptivity representing key contributors to poor assisted reproductive technology (ART) outcomes. Platelet-rich plasma (PRP), an autologous blood-derived concentrate enriched with growth factors and cytokines, has emerged as a promising regenerative therapy with angiogenic, anti-apoptotic, and proliferative properties. In reproductive medicine, intraovarian PRP has been evaluated for its potential to restore ovarian function in women with DOR and POI, improve oocyte competence and embryo euploidy, and promote ovulation in PCOS. Similarly, intrauterine PRP infusion or subendometrial zone injections has shown encouraging results in women with recurrent implantation failure and thin endometrium, enhancing endometrial thickness, receptivity, and implantation potential. Evidence from preclinical animal models and early clinical studies suggests multi-level mechanisms of action, including modulation of endocrine pathways, reduction in oxidative stress, activation of dormant follicles, and improvement of endometrial angiogenesis and receptivity. Despite these promising findings, results remain inconsistent due to heterogeneity in PRP preparation protocols, administration routes, timing, and study designs. Even though robust randomized controlled trials with standardized methodologies are needed to determine the efficacy and long-term reproductive outcomes of PRP in infertility treatment and anovulation in PCOS, PRP represents a novel and potentially transformative adjunct in reproductive endocrinology. Full article

Polycystic ovary syndrome (PCOS) is a systemic metabolic and endocrine disorder that significantly disrupts reproductive physiology and endometrial function. In this narrative review, we examine the molecular impact of metabolic and hormonal imbalances on the endometrium of women with PCOS. We investigate the specific mechanisms that delineate how hyperinsulinemia and insulin resistance, chronic low-grade inflammation, and estrogen/progesterone/androgen imbalance contribute to altered epigenetic, transcriptomic, metabolomic, and signaling profiles in a wide array of different cell types within endometrial tissues. The synergistic interplay between upregulated inflammatory cytokines (e.g., IL-1,2,6,8,17,18, and TNF-α), along with key changes in critical molecular pathways associated with hyperinsulinemia and insulin resistance (e.g., PI3K/AKT/MAPK, and Wnt/β-catenin), in addition to aberrant sex steroid hormone signaling (e.g., CYP19A1, COX-2, PGE₂, HOXA10, 11βHSD2), promotes deleterious changes within the endometrial microenvironment. These anomalies underpin a spectrum of clinical manifestations observed in women with PCOS at each stage of the life course, including abnormal uterine bleeding in reproductive-age women, impaired decidualization in pregnancy, and altered postmenopausal endometrial physiology. Clinically, these alterations are associated with abnormal uterine bleeding, subfertility, implantation failure, miscarriage, pregnancy complications, and postmenopausal endometrial hyperplasia and cancer. Overall, our review provides novel insights into the molecular mechanisms linking systemic metabolic and endocrine dysfunction with endometrial pathology in PCOS and has broader implications that apply to all women. Full article

Varuna litterata is an estuarine crab species widely distributed across the Indo-Pacific region, commonly dwelling in brackish waters, mangrove forests, and tidal estuaries. In Bangladesh, while four Scylla species dominate the commercial crab market, the locally consumed V. litterata remains a biologically overlooked gem of the coastal waters. These crabs are frequently captured as a byproduct during shrimp fry collection from coastal estuaries. In this context, the current study investigates the reproductive biology, morphometric dynamics, and market potential of V. litterata collected from the Pasur River, a coastal mangrove forest-adjacent estuary of southern Bangladesh. A total of 75 individuals were collected from March to April 2023, comprising 35 males and 40 females, resulting in a sex ratio of 1:1.14 (♂:♀), with a predominance of females. A visual observation of ovary development revealed four distinct maturation stages, with Stage IV (fully mature) being the most prevalent (43%), indicating peak reproductive activity during the sampling period. Morphometric analysis revealed that the average carapace width (CW) was 31.2 ± 5.7 mm and 31.9 ± 5.8 mm and the mean carapace length (CL) was 29.3 ± 4.7 mm and 30.1 ± 4.9 mm in males and females, respectively. However, the mean body weight (BW) was 13.1 ± 4.3 g in males and 12.7 ± 3.8 g in female crabs. The dominant CW class ranges from 33 to 33.99 mm (males) and 28.99–29.99 mm (females), appear to be the most vulnerable to fishing pressure. BW-CW and CL-CW relationships demonstrated negative allometric growth, with high correlations in both sexes. Significant sexual dimorphism was observed, with males having larger cheliped dimensions, while females had broader abdomens, likely supporting reproductive functions that are essential to their conservation. The marketing of this crab remains largely informal, yet rising local demand and prices highlight its emerging commercial potential. Therefore, incorporation into aquaculture and coastal fishery development of this crab species could enhance food security, support livelihoods, and contribute to sustainable blue economy initiatives in Bangladesh. Full article

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

The ovary is among the earliest organs to undergo age-related degeneration, limiting the reproductive potential of elite horses and constraining the growth of the equine industry. Follicular development during estrus is a key determinant of fertility, yet the molecular mechanisms underlying its decline, particularly at the level of specific ovarian cell types, remain poorly understood in equids. Here, we constructed a single-cell transcriptomic atlas to investigate ovarian changes in Kazakh horses. Using single-cell RNA sequencing (scRNA-seq), we profiled 112,861 cells from follicle-containing and follicle-absent ovaries, identifying nine distinct ovarian cell types and their subtypes, each with distinct gene expression signatures. Functional enrichment analyses revealed cell type-specific engagement in biological pathways, including ECM–receptor interaction, PI3K-Akt signaling, and oxytocin signaling. Gene expression patterns indicated tightly regulated processes of ovarian activation and cell differentiation. Notably, stromal cells exhibited high expression of ROBO2, LOC111770199, and TMTC2, while smooth muscle cells (SMCs) were marked by elevated levels of CCL5, KLRD1, and NKG7. Moreover, cell–cell interaction analyses revealed robust signaling interactions among SMCs, endothelial cells, neurons, and proliferating (cycling) cells. Together, these findings provide a comprehensive single-cell transcriptomic map of normal and abnormal ovarian states during estrus in Kazakh horses, offering novel insights into the cellular mechanisms of follicular development and identifying potential diagnostic biomarkers and therapeutic targets for ovarian quiescence in equids. Full article

The Nile tilapia (Oreochromis niloticus), a key aquaculture species, displays marked sexual growth dimorphism, with males growing faster than females. This process is governed by intricate interactions between antagonistic regulators, including transcription factors, growth factors, and steroid hormones, operating through sex-specific developmental pathways. While circular RNAs (circRNAs) are known to modulate gene expression by sponging microRNAs (miRNAs), their role in teleost sex differentiation remains poorly understood. To address this gap, we profiled circRNA expression in tilapia gonads by constructing six circRNA libraries from testes and ovaries of 180 days after hatching (dah) fish, followed by high-throughput sequencing. We identified 6564 gonadal circRNAs distributed across all 22 linkage groups, including 226 differentially expressed circRNAs (DECs; 108 testis-biased, 118 ovary-biased). Functional enrichment analysis linked their host genes to critical pathways such as cAMP signaling, cell adhesion molecules, and—notably—sexual differentiation processes (e.g., estrogen signaling, oocyte meiosis, and steroid hormone biosynthesis). Furthermore, we deciphered competing endogenous RNA (ceRNA) networks, uncovering circRNA–miRNA–mRNA interactions targeting germ cell determinants, sex-specific transcription factors, and steroidogenic enzymes. This study provides the first systematic exploration of circRNA involvement in tilapia sex differentiation and gonadal differentiation, offering novel insights into the post-transcriptional regulation of sexual dimorphism. Our findings advance the understanding of circRNA biology in fish and establish a framework for future studies on aquaculture species with similar reproductive strategies. Full article

The aim of this study was to evaluate the effects of Flos lonicerae and Baikal skullcap extracts (PE) on laying performance, antioxidant capacity, immune function, follicular development, estrogen secretion, ovarian metabolomics, and cecal microbiota in aged laying hens. The total number of 70-week-old XinYang Black-Feathered laying hens was 240. These hens were randomly divided into two groups, with each group consisting of six replicates of 20 birds. Control (CON) group was fed a basal diet, whereas the PE group received the same basal diet supplemented with 500 mg/kg of PE. The duration of the experiment was 10 weeks. The findings indicated that the supplementation of PE improved laying performance, antioxidant capacity, and immune function. This was reflected by significant increases (p < 0.05) in laying rate, feed conversion ratio, antioxidant indicators (such as glutathione peroxidase, total antioxidant capacity, and catalase), and immunoglobulin levels. Additionally, there were notable decreases (p < 0.05) in the malondialdehyde levels and pro-inflammatory markers. Moreover, the PE group exhibited a greater number of large yellow and white follicles, as well as higher serum estrogen levels, compared to the CON group (p < 0.05). 16S rRNA sequencing revealed that PE supplementation altered the composition of the cecal microbiota by increasing Ruminococcus_torques_group, Butyricoccus and Christensenellaceae_R-7_group abundances and decreasing Bacteroides, Prevotellaceae_UCG-001 and Megamonas abundances (at genus level), which are primarily associated with short-chain fatty acid production. Ovarian metabolomic analysis showed that the major metabolites altered by PE supplementation were mainly involved in follicular development, estrogen biosynthesis, anti-inflammatory and antioxidant properties. Moreover, changes in both the cecal microbiota (at genus level) and ovarian metabolites were strongly correlated with laying performance, antioxidant status, and immune function. In conclusion, PE supplementation improved laying performance in aged hens by enhancing antioxidant, immune, and ovarian functions, promoting follicular development and estrogen secretion, and modulating the gut microbiota and ovarian metabolites. These findings will offer novel insights into the mechanisms that underlie egg production in the ovaries of aged poultry. Full article

Positioned at the intersection of sex medicine and endocrinology, metabolic dysfunction-associated steatotic liver disease (MASLD) is often managed by specialists who may not be fully familiar with the complex roles of sex hormones in its pathogenesis and clinical course. To address this gap, we review the molecular actions of testosterone, estradiol, and progesterone on liver functions, as well as the role of sex-hormone binding globulin (SHBG) in MASLD histogenesis, highlighting disparities by sex as well as reproductive status. We also discuss how sex hormones influence fatty acid metabolism, gut dysbiosis, mitochondrial activity, gluco-lipidic homeostasis, lipotoxicity, inflammation, and MASLD-related liver tumorigenesis. Furthermore, we examine observational studies on associations between endogenous and exogenous sex hormones and SHBG with MASLD, with attention to hypogonadism in either sex or polycystic ovary syndrome. We summarize the role of sex hormones in modulating MASLD risk across life stages such as menopause, breastfeeding, and lactation. Lastly, we review the hepatic effects of hormone replacement therapy (HRT) on MASLD in both sexes, prospects, and safety of HRT and contraceptives among individuals with chronic liver disease. In conclusion, sex hormones play significant roles in MASLD pathobiology, underscoring the importance of sex-specific approaches in clinical practice and research. Full article

The female reproductive system represents a highly complex regulatory network governing critical physiological functions, encompassing reproductive capacity and endocrine regulation that maintains female physiological homeostasis. The in vitro simulation system provides a novel tool for biomedical research and can be used as physiological and pathological models to study the female reproductive system. Recent advances in this technology have evolved from 2D and 3D printing to organ-on-a-chip (OOC) and microfluidic systems, which has emerged as a transformative platform for modeling the female reproductive system. These microphysiological systems integrate microfluidics, 3D cell culture, and biomimetic scaffolds to replicate key functional aspects of reproductive organs and tissues. They have enabled precise simulation of hormonal regulation, embryo-endometrium interactions, and disease mechanisms such as endometriosis and gynecologic cancers. This review highlights the current state of female reproductive OOCs, including ovary-, uterus-, and fallopian tube-on-a-chip system, their applications in assisted reproduction and disease modeling, and the technological hurdles to their widespread application. Though significant barriers remain in scaling OOCs for high-throughput drug screening, standardizing protocols for clinical applications, and validating their predictive value against human patient outcomes, OOCs have emerged as a transformative platform to model complex pathologies, offering unprecedented insights into disease mechanisms and personalized therapeutic interventions. Future directions, including multi-organ integration for systemic reproductive modeling, incorporation of microbiome interactions, and clinical translation for mechanisms of drug action, will facilitate unprecedented insights into reproductive physiology and pathology. Full article