Search Results (201)

High non-esterified fatty acids (NEFAs) during negative energy balance in dairy cattle can impair reproduction. While their effects on oocyte maturation and preimplantation embryo development are known, their impact during fertilisation is largely unexplored. This study examined the effects of high NEFA exposure exclusively during in vitro fertilisation (IVF). Bovine oocytes were matured in vitro and fertilised under physiological or high NEFA concentrations. High NEFA concentrations decreased fertilisation, cleavage, and blastocyst rates. Reactive oxygen species production in zygotes was not affected, but blastocysts derived from the High-NEFA group had fewer cells. Spermatozoa exposed to high NEFA concentrations exhibited increased plasma membrane and acrosome damage, higher DNA fragmentation, and reduced mitochondrial membrane potential. The expression of H3K27me3, a repressive histone mark normally erased from fertilisation to embryonic genome activation, was higher in 2-cell than in 4-cell embryos on day 2 after IVF, but only in the High-NEFA group. This delayed H3K27me3 loss, along with increased DNA damage, could partially explain the reduced blastocyst formation observed. In conclusion, high NEFA concentrations can impair pre-implantation embryo development during zygote formation, potentially via effects on both the oocyte and spermatozoon. The latter warrants further investigation using an intracytoplasmic sperm injection model. Full article

Endocrine-disrupting chemicals (EDCs) have raised increasing concern due to their potential effects on reproductive health. This review focuses on the impact of EDCs, particularly bisphenol A (BPA) and its analogues, and per- and polyfluoroalkyl substances (PFAS), on domestic ruminants (cattle and sheep) by integrating findings from both in vitro and in vivo studies. The analysis highlights how exposure to EDCs affects steroidogenesis, oxidative stress responses, apoptosis, epigenetic regulation, and overall fertility markers, such as oocyte maturation, sperm motility, and embryo developmental competence. While most data originate from in vitro bovine studies, in vivo research in sheep offers valuable insights. Importantly, given the potential for EDCs to bioaccumulate in animal tissues, these findings hold significant implications for animal health, particularly regarding reproductive physiology and fertility rates. 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

Aquaporins (AQPs) are membrane proteins that facilitate the transport of water and solutes. Among AQPs, plasma membrane intrinsic proteins (PIPs) play a critical role in maintaining water balance between the internal and external cell environments. This study focuses on the tomato due to its economic importance and cultivation under moderate salinity conditions in Japan. A swelling assay using X. laevis oocyte confirmed that all five examined tomato SlPIP2 isoforms showed water transport activity. Among them, two-electrode voltage clamp (TEVC) experiments showed that only SlPIP2;1, SlPIP2;4, and SlPIP2;8 transport Na⁺ and K⁺, with no transport activity for Cs⁺, Rb⁺, Li⁺, or Cl⁻. CaCl₂ (1.8 mM) reduced ionic currents by approximately 45% compared to 30 µM free-Ca²⁺. These isoforms function as very low-affinity Na⁺ and K⁺ transporters. Expression analysis showed that SlPIP2;4 and SlPIP2;8 had low, stable expression, while SlPIP2;1 was strongly upregulated in roots NaCl treatment (200 mM, 17days), suggesting distinct physiological roles for these ion-conducting AQPs (icAQPs). These data hypothesized that tomato icAQPs play a critical role in ion homeostasis, particularly under salinity stress. In conclusion, the first icAQPs have been identified in the dicotyledonous crop. These icAQPs are essential for plant resilience under salt stress. Full article

The Kazakh horse, one of China’s indigenous primitive breeds, is renowned for its remarkable adaptability and distinctive physiological traits. The ovary is a vital reproductive organ in female animals, responsible for oocyte production and hormone secretion. However, limited research has been conducted on gene expression profiles in the ovarian tissue of equine species. To address this gap, the present study performed transcriptomic sequencing on ovarian tissues from 12 Kazakh horses in different physiological states. A total of 979 differentially expressed mRNAs were identified, including 619 upregulated and 360 downregulated genes. Among these, key genes such as COL1A1, LHCGR, KISS1, NTRK2, COL1A2, and THBS4 were identified as differentially expressed. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that 374 of these genes were primarily involved in ovarian steroidogenesis, the PI3K-Akt signaling pathway, and ECM-receptor interactions among 292 enriched pathways. This study provides a comprehensive transcriptomic profile of equine ovarian tissue, offering in-depth insights into differential gene expression and signal pathways associated with ovarian development in Kazakh horses, providing theoretical foundations and referential data for future research in equine ovarian development and reproductive studies. Full article

The initial molecular events mediating mammalian sperm binding to the zona pellucida (ZP) of the oocyte are highly complex and still not fully elucidated. Recent advances have identified multiple candidate sperm surface proteins, often functioning as part of high-molecular-weight complexes that mediate this critical fertilization event in a species-specific and coordinated manner. To address a significant gap in the literature, we provide an in-depth overview of the functional assays employed to investigate sperm–ZP interactions, emphasizing their underlying principles, potential applications, and key methodological strengths and limitations. The techniques discussed range from classical in vitro sperm–oocyte and hemizona binding assays, including antibody-blocking and competitive strategies, to cutting-edge in vivo genetic models, each contributing unique insights into the physiological relevance of the proposed ZP receptors. Robust experimental design, including the use of appropriate controls and validation strategies, is essential for accurately interpreting the role of candidate sperm receptors. This review provides a structured overview of current methodologies to support researchers in critically evaluating and applying functional assays in future studies. 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

This review aims to discuss how heat stress affects ovarian follicles and oocytes, steroidogenesis, and embryo development in ruminants. The literature shows that quiescent primordial follicles appear to be less susceptible to heat stress, but from the primary follicle stage onwards, they begin to suffer the consequences of heat stress. These adverse effects are exacerbated when the follicles are cultured in vitro. In antral follicles, heat stress reduces granulosa cell viability and proliferation in both in vivo and in vitro models. Oocyte maturation, both nuclear and cytoplasmic, is also compromised, and embryo quality declines under elevated thermal conditions. These effects are linked to intracellular disturbances, including oxidative imbalance, mitochondrial dysfunction, and altered hormonal signaling. The differences between in vivo and in vitro responses reflect the complexity of the biological impact of heat stress and emphasize the protective role of the physiological microenvironment. A better understanding of how heat stress alters the function of ovarian follicles, oocytes, and embryos is crucial. This knowledge is critical to devise effective strategies that mitigate damage, support fertility, and improve outcomes in assisted reproduction for livestock exposed to high environmental temperatures. Full article

Background: Against the backdrop of the large-scale and intensive development of the livestock industry, enhancing the reproductive efficiency of cattle has become a crucial factor in industrial development. Holstein cows, as the most predominant dairy cattle breed globally, are characterized by high milk yield and excellent milk quality. However, their reproductive efficiency is comprehensively influenced by a variety of complex factors, and improving their reproductive performance faces numerous challenges. The ovary, as the core organ of the female reproductive system, plays a decisive role in embryonic development and pregnancy maintenance. It is not only the site where eggs are produced and developed but it also regulates the cow’s estrous cycle, ovulation process, and the establishment and maintenance of pregnancy by secreting various hormones. The normal functioning of the ovary is crucial for the smooth development of the embryo and the successful maintenance of pregnancy. Methods: Currently, traditional sequencing technologies have obvious limitations in deciphering ovarian function and reproductive regulatory mechanisms. To overcome the bottlenecks of traditional sequencing technologies, this study selected Holstein cows as the research subjects. Ovarian samples were collected from one pregnant and one non-pregnant Holstein cow, and single-nucleus transcriptome sequencing technology was used to conduct an in-depth study on the ovarian cells of Holstein cows. Results: By constructing a cell type-specific molecular atlas of the ovaries, nine different cell types were successfully identified. This study compared the proportions of ovarian cell types under different physiological states and found that the proportion of endothelial cells decreased during pregnancy, while the proportions of granulosa cells and luteal cells increased significantly. In terms of functional enrichment analysis, oocytes during both pregnancy and non-pregnancy play roles in the “cell cycle” and “homologous recombination” pathways. However, non-pregnant oocytes are also involved in the “progesterone-mediated oocyte maturation” pathway. Luteal cells during pregnancy mainly function in the “cortisol synthesis and secretion” and “ovarian steroidogenesis” pathways; non-pregnant luteal cells are mainly enriched in pathway processes such as the “AMPK signaling pathway”, “pyrimidine metabolism”, and “nucleotide metabolism”. Cell communication analysis reveals that there are 51 signaling pathways involved in the pregnant ovary, with endothelial cells, granulosa cells, and luteal cells serving as the core communication hubs. In the non-pregnant ovary, there are 48 pathways, and the interaction between endothelial cells and stromal cells is the dominant mode. Conclusions: This study provides new insights into the regulatory mechanisms of reproductive efficiency in Holstein cows. The differences in the proportions of ovarian cell types, functional pathways, and cell communication patterns under different physiological states, especially the increase in the proportions of granulosa cells and luteal cells during pregnancy and the specificity of related functional pathways, indicate that these cells play a crucial role in the reproductive process of cows. These findings also highlight the importance of ovarian cells in pathways such as “cell cycle”, “homologous recombination”, and “progesterone-mediated oocyte maturation”, as well as the cell communication mechanisms in regulating ovarian function and reproductive performance. Full article

Background: Nitric oxide (NO) is an important modulator of ovarian physiology, which contributes to angiogenesis, steroidogenesis, and redox control. The stable metabolites nitrate (NO₃⁻) and nitrite (NO₂⁻) may indicate real-time follicular function during IVF. Methods: In this prospective study, we included 89 women who underwent controlled ovarian stimulation. The Griess test was used to measure NO₂-NO₃ concentrations in follicular fluid collected on the day of oocyte retrieval. Non-parametric and correlation tests were used to investigate the associations between oocyte yield, maturity (MII), fertilization (2PN), embryo development, and hormone levels. Results: Higher NO₂-NO₃ levels were substantially associated with increased total oocyte count, MII oocytes (p = 0.014), and 2PN embryos (p = 0.029). This suggests a strong relationship between NO bioavailability and oocyte competence. NO₂-NO₃ levels showed a positive correlation with estradiol (p < 0.001) and progesterone (p < 0.001), suggesting a possible function in granulosa cell steroidogenesis. Conclusions: Follicular NO metabolites are candidate functional indicators for oocyte quality evaluation and intrafollicular steroidogenic activity. Their predictive value may improve customized IVF treatment, especially in individuals with complicated ovarian phenotypes such as PCOS or decreased ovarian reserve. 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

Oocyte maturation represents a fundamental biological process in bovine reproduction, establishing the physiological basis for fertilization and early embryonic development while critically determining the propagation of improved varieties and breeding efficiency. The roles of MQC in reproduction have gained substantial scientific attention. The proper maturation of oocytes fundamentally depends on adequate mitochondrial functionality. However, the intrinsic regulatory mechanisms governing MQC during bovine oocyte maturation remain incompletely characterized. Here, we discuss the most recent progress on the molecular mechanisms and roles of mitochondrial fission/fusion, biogenesis, and mitophagy in MQC. Building upon the mechanistic foundations of MQC in bovine oocyte maturation, this review identifies key mitochondrial-targeted supplements with potential applications in enhancing oocyte quality. Furthermore, we evaluate epigenetic influences on mitochondrial regulatory networks through mitochondrial–nuclear communication. Finally, we discuss the challenges in elucidating mitochondrial quality control mechanisms during oocyte maturation and propose corresponding strategies to address these obstacles. Integrating mechanistic insights, this review proposes strategies to enhance in vitro culture systems and identify oocyte quality markers, providing valuable insights for optimizing in vitro production (IVP) of bovine embryos and enhancing reproductive efficiency. Full article

Corazonin (Crz) is widely found in insects and crustaceans. In insects, Crz participates in the regulation of various physiological activities, including heartbeat, body color change, molting, and reproduction. However, the physiological effects of Crz in crustaceans remain largely unclear. In this study, the cDNAs encoding Crz and its putative receptor were isolated from the mud crab Scylla paramamosain. Tissue distribution analysis revealed that Sp-Crz was predominantly expressed in neural tissues, while its receptor (Sp-CrzR) was widely expressed in S. paramamosain, with a high expression level in the Y-organ. During ovarian development, Sp-Crz expression in the eyestalk ganglion was upregulated at the early and late vitellogenic stages, whereas its expression level in the cerebral ganglion displayed an initial downregulation at the early stage, followed by a remarkable upregulation at the late vitellogenic stage. The expression level of Sp-CrzR mRNA in the ovary increased significantly at the late vitellogenic stage. However, an opposite expression pattern was observed in the hepatopancreas and Y-organ. The immunohistochemistry result showed that Sp-Crz was distributed in the cells of the lamina ganglionaris, the medulla interna, and the X-organ of the eyestalk ganglion. It was revealed that the level of Sp-Vg in the hepatopancreas was not affected by the addition of Sp-Crz in vitro. However, the expression of Sp-VgR in ovarian explants was significantly induced by 6 h treatment with Sp-Crz at a concentration of 1 nM. In addition, the level of Sp-VgR in the ovary was significantly upregulated by 12 h injection of Sp-Crz. After long-term administration of Sp-Crz, the expression of Sp-VgR in the ovary, the E₂ content in hemolymph, the oocyte diameter, and the gonadosomatic index of S. paramamosain were significantly increased. In summary, these findings collectively indicate that the Sp-Crz signaling system participates in regulating the ovarian development of the mud crab. This study provides a new insight into the biological function of Crz during the ovarian development of the mud crab, which is of great significance for the sustainable development and utilization of mud crab resources. Full article

The asynchrony of cytoplasmic and nuclear maturation in cumulus–oocyte complexes (COCs) due to prematurely declining concentrations of cyclic adenosine monophosphate (cAMP) has been shown to result in reduced oocyte developmental competence. The objective of this study was to evaluate the effect of pre-IVM treatment with cAMP modulators for different durations on the developmental potential of equine oocytes used for cloned embryo production. Collected COCs were transferred to cryovials filled with transport medium at 20–22 °C. Within the cryovials, the COCs were either untreated (Control) for 18 h or treated with 50 µM forskolin and 100 µM 3-isobutyl-1-methylxanthine for the first 4 h (Pre-IVM 4 h) or the entire 18 h (Pre-IVM 18 h). Oocytes were then transferred to maturation medium and incubated for a further 22–24 h at 38.5 °C in 5% CO₂ in air. Somatic cell nuclear transfer embryos were then produced using the meiotically mature oocytes and donor cells from six different fibroblast cell lines. The rates of maturation and embryo development did not differ significantly between the groups, though blastocyst formation tended to be inferior in the Pre-IVM 4 h group compared with the Control group (p = 0.06). Of 67 blastocysts produced, 23 were transferred to recipient mares on Day 4 or 5 post-ovulation. Regarding the pregnancy outcomes, no significant differences were found between the groups, and four viable foals were born, each derived from a different donor cell line. The findings expand on those from previous evaluations of this biphasic IVM system, and indicate that the cAMP-modulating treatments exert limited effects under the pre-IVM conditions used here. Full article