Oocyte Maturation Research Articles

Increased in vitro production of bovine embryos resulting from oocyte maturation in the presence of triciribine, a specific inhibitor of AKT

The aim of this study was to evaluate the effect of different concentrations of triciribine, a selective Akt inhibitor, on various aspects of oocyte maturation and on the IVF of bovine embryos. Cumulus-oocyte complexes (COCs) were matured in vitro in medium supplemented with: 0 (control), 1, 5, 10, and 20 μM of triciribine. The nuclear maturation was assessed by staining with acetic orcein, while the cytoplasmic maturation was evaluated by mitochondrial (MitoTracker® Red CMXRos) and lipid droplets distribution (LipidTOX). COCs were fertilized in vitro and cultured for nine days. Cleavage rates, blastocyst production, and hatching rates were determined on days three, seven, and nine of in vitro culture, respectively. Oocytes from COCs treated with 1 μM of triciribine were stained at 3, 6, and 9 h of IVM to determine the inhibitor's involvement in germinal vesicle breakdown. Analysis of variance (ANOVA) of the data was performed and the means were compared using the SNK test at a 5 % significance level. Exposure of COCs to 1, 5, and 10 μM of triciribine did not alter the number of matured oocytes (P < 0.05), a concentration of 20 μM reduced the number of oocytes in MII with a consequent increase in oocytes in MI (P < 0.05). This concentration markedly reduced the number of oocytes with peripheral cortical granules and the rates of cleavage and blastocysts (P < 0.05). On the other hand, when COCs were matured in the presence of 1 μM, there was an increase in the blastocyst rate (P < 0.05), but without altering the timing of meiosis resumption (P < 0.05). It is concluded that the Akt pathway participates in the nuclear and cytoplasmic events of in vitro maturation of bovine oocytes, but through mechanisms that do not interfere with germinal vesicle breakdown. Modulation of Akt activity in bovine COCs during IVM with 1 μM of triciribine increases the in vitro production of bovine embryos.

A Compound Heterozygous Pathogenic Variant in ZP2 Gene Causes Female Infertility.

The oocyte maturation defect 6 is an autosomal recessive hereditary disease caused by a homozygous variant in ZP2 gene. It is characterized by female primary infertility due to an abnormally thin zona pellucida (ZP) and defective sperm binding. Here we identified a compound heterozygous variant (c.1924C > T and c.1695-2A > G) in ZP2 gene in a Chinese Han family. Quantitative real-time PCR showed that the variant c.1924C > T significantly decreased the expression of truncated ZP2message RNA by the nonsense-mediated decay pathway. Minigene assays showed the c.1695-2A > G variant led to an extra-61-nt preservation of intron 15 at the junction between exons 15 and 16 during transcription. Both variants (c.1924C > T and c.1695-2A > G) resulted in truncated ZP2 proteins (p.R642X and p.C566Hfs*2) that lost the transmembrane domain, which prevented the secretion of the mutant ZP2 proteins and produced a structurally abnormal ZP, thus resulting in female infertility. This study further elucidated the pathogenic mechanism of these two variants and provided new support for the genetic diagnosis of female infertility.

Investigation of FF-MAS oxysterole’s role in follicular development and its relation to hedgehog signal pathway

The Hedgehog signaling pathway plays a crucial role in folliculogenesis; however, the association between FF-MAS oxysterol activity in folliculogenesis and the Hedgehog signaling pathway has not been revealed. The evaluation of FF-MAS activity in polycystic ovary syndrome (PCOS) with folliculogenesis disorder might provide a new approach to tackle follicular and oocyte maturation failure. The question is: does FF-MAS oxysterol affect granulosa cell (GC) proliferation? If so, is this effect facilitated through the Hedgehog pathway? To answer these questions, GCs were isolated from follicle fluids obtained from patients undergoing oocyte retrieval during in vitro fertilization (IVF) treatment. After the isolated GCs were incubated in different cell culture media, the levels of Hedgehog pathway components (SMO, Gli1) were measured by using immunohistochemical methods, cytoELISA, and qRT-PCR. Meanwhile, cell proliferation rates were determined. Significant increases (p < 0.001) in SMO and Gli1 expressions and cell proliferation were observed in the FF-MAS-treated subgroups of both PCOS and male factor participants compared to the FF-MAS deficient subgroup. Remarkably, FF-MAS positively affected the pathway components despite the pathway inhibitor cyclopamine. Although the increase in Hedgehog pathway components was slightly higher in the male factor group (MF), it was not statistically significant. In our study, we demonstrated for the first time the molecular effect of FF-MAS on human GCs in folliculogenesis. Since FF-MAS is already used in assisted reproductive techniques in animals and is known to be synthesized in the human body, it could be considered a new approach in human IVF treatments.

Identification of key signaling pathways and novel computational drug target for oral cancer, metabolic disorders and periodontal disease

AimDue to conventional endocrinological methods, there is presently no shared work available, and no therapeutic options have been demonstrated in oral cancer (OC) and periodontal disease (PD), type 2 diabetes (T2D), and obese patients. The aim of this study is to determine the similar molecular pathways and potential therapeutic targets in PD, OC, T2D, and obesity that may be used to anticipate the progression of the disease. MethodsFour Gene Expression Omnibus (GEO) microarray datasets (GSE29221, GSE15773, GSE16134, and GSE13601) are used for finding differentially expressed genes (DEGs) for T2D, obese, and PD patients with OC in order to explore comparable pathways and therapeutic medications. Gene ontology (GO) and pathway analysis were used to investigate the functional annotations of the genes. The hub genes were then identified using protein-protein interaction (PPI) networks, and the most significant PPI components were evaluated using a clustering approach. ResultsThese three gene expression-based datasets yielded a total of seven common DEGs. According to the GO annotation, the majority of the DEGs were connected with the microtubule cytoskeleton structure involved in mitosis. The KEGG pathways revealed that the concordant DEGs are connected to the cell cycle and progesterone-mediated oocyte maturation. Based on topological analysis of the PPI network, major hub genes (CCNB1, BUB1, TTK, PLAT, and AHNAK) and notable modules were revealed. This work additionally identified the connection of TF genes and miRNAs with common DEGs, as well as TF activity. ConclusionPredictive drug analysis yielded concordant drug compounds involved with T2D, OC, PD, and obesity disorder, which might be beneficial for examining the diagnosis, treatment, and prognosis of metabolic disorders and Oral cancer.

Heat stress: a major threat to ruminant reproduction and mitigating strategies.

Stress is an external event or condition that puts pressure on a biological system. Heat stress is defined as the combination of internal and external factors acting on an animal to cause an increase in body temperature and elicit a physiological response. Heat stress is a set of conditions caused by overexposure to or overexertion at excess ambient temperature and leads to the inability of animals to dissipate enough heat to sustain homeostasis. Heat exhaustion, heat stroke, and cramps are among the symptoms. For the majority of mammalian species, including ruminants, heat stress has a negative impact on physiological, reproductive, and nutritional requirements. Reproductive functions, including the male and female reproductive systems, are negatively affected by heat stress. It decreases libido and spermatogenic activity in males and negatively affects follicle development, oogenesis, oocyte maturation, fertilization, implantation, and embryo-fetal development in females. These effects lead to a decrease in the rate of reproduction and financial losses for the livestock industry. Understanding the impact of heat stress on reproductive tissues will aid in the development of strategies for preventing heat stress and improving reproductive functions. Modification of the microenvironment, nutritional control, genetic development of heat-tolerant breeds, hormonal treatment, estrous synchronization, timed artificial insemination, and embryo transfer are among the strategies used to reduce the detrimental effects of heat stress on reproduction. These strategies may also increase the likelihood of establishing pregnancy in farm animals.

The Effect of Simulated Physiological Oocyte Maturation (SPOM) and L-Carnitine on Bovine Oocyte Developmental Competence

Background: Simulated Physiological Oocyte Maturation (SPOM) mimics in vitro the physiological events of oocyte maturation in the presence of cAMP modulators. These modulators increase the intracellular concentrations of cAMP, which inhibits the immediate resumption of meiosis and gives the oocyte more time to gain optimal developmental competence. In addition, L-carnitine helps to increase the energy supply of cells through the β-oxidation of fatty acids. This study aimed to investigate the effect of SPOM and L-carnitine supplementation during In Vitro Maturation (IVM) and In Vitro Culture (IVC) on the developmental competence of bovine oocytes. Methods: Ovarian Cumulus Complexes (COCs) were cultured in the presence or absence of forskolin+IBMX during the first 2 hr of IVM (pre-IVM) with or without L-carnitine (LC) during IVM or IVC in six experimental groups as follows: I) pre-IVM (pre-IVM group), II) pre-IVM with L-carnitine supplementation during IVM (pre-IVM/LC group), III) L-carnitine supplementation during IVM (IVM/LC group), IV) L-carnitine supplementation during in vitro culture (IVC/LC group), V) pre-IVM+ IVC/LC group, and VI) no treatment during IVM and IVC (Control group). The cleavage and blastocyst rates, the blastocysts’ total cells number, and the expression of Nanog, Bax, Oct4, Cdx2, and Ifnt genes in resulting blastocysts were assessed. To assess differences among experimental groups, a one-way analysis of variance was initially employed, followed by post hoc Fisher LSD. The difference between groups was considered statistically significant when p&lt;0.05. Results: The cleavage and blastocyst rates in the Pre-IVM and Pre-IVM/LC groups was higher than control group and other groups (p≤0.05) except for IVC/LC and IVM/LC groups, respectively. The number of blastocyst’s Inner Cell Mass (ICM) in pre-IVM and Pre-IVM/LC groups as well as the ratio of ICM/TE were higher than control group (p&lt;0.05). The expression of OCT4, CDX2, and IFNT increased in both the pre-IVM and pre-IVM/LC groups compared to the control group (p&lt;0.05). Conclusion: In conclusion, the application of SPOM-adapted IVM and L-carnitine during IVM of bovine oocyte improves the quantity and quality of the resulting embryos.

Transcriptome analysis in C. elegans early embryos upon depletion of the Topoisomerase 2/condensin II axis.

In C. elegans , the chromosome compaction factors topoisomerase 2 (TOP-2) and condensin II have been shown to globally repress transcription in multiple contexts. Our group has previously reported that TOP-2 and condensin II repress transcription in the C. elegans germline during larval starvation, oocyte maturation, and in germline progenitor cells of the early embryo. Here, we assess the transcriptome of early embryos treated with RNAi against TOP-2 and the condensin II subunit CAPG-2. We found 144 upregulated and 172 downregulated genes. Further analysis showed that the upregulated genes are mostly somatic, with a host of neuronal cells present in our tissue enrichment analysis.

In vitro maturation of oocytes: what is already known?

Assisted reproductive technologies (ARTs) involve the laboratory manipulation of gametes and embryos to help couples with fertility problems become pregnant. One of these procedures controlled ovarian stimulation uses pharmacological agents to induce ovarian and follicular maturation in vivo. Despite the effectiveness in achieving pregnancy and live births, some patients may have complications due to over-response to gonadotropins and develop ovarian hyperstimulation syndrome (OHSS). In vitro maturation of oocytes (IVM) has emerged as a technique to reduce the risk of OHSS, particularly in women with polycystic ovary syndrome (PCOS), and for fertility preservation in women undergoing oncological treatment. Although there are some limitations, primarily due to oocyte quality, recent advances have improved pregnancy success rates and neonatal and infant outcomes. Different terms have been coined to describe variations of IVM, and the technique has evolved with the introduction of hormones to optimize results. This review we provide a comprehensive overview of IVM and its reproductive outcomes during ARTs.

Brain-Region-Specific Differences in Protein Citrullination/Deimination in a Pre-Motor Parkinson's Disease Rat Model.

The detection of early molecular mechanisms and potential biomarkers in Parkinson's disease (PD) remains a challenge. Recent research has pointed to novel roles for post-translational citrullination/deimination caused by peptidylarginine deiminases (PADs), a family of calcium-activated enzymes, in the early stages of the disease. The current study assessed brain-region-specific citrullinated protein targets and their associated protein-protein interaction networks alongside PAD isozymes in the 6-hydroxydopamine (6-OHDA) induced rat model of pre-motor PD. Six brain regions (cortex, hippocampus, striatum, midbrain, cerebellum and olfactory bulb) were compared between controls/shams and the pre-motor PD model. For all brain regions, there was a significant difference in citrullinated protein IDs between the PD model and the controls. Citrullinated protein hits were most abundant in cortex and hippocampus, followed by cerebellum, midbrain, olfactory bulb and striatum. Citrullinome-associated pathway enrichment analysis showed correspondingly considerable differences between the six brain regions; some were overlapping for controls and PD, some were identified for the PD model only, and some were identified in control brains only. The KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways identified in PD brains only were associated with neurological, metabolic, immune and hormonal functions and included the following: "Axon guidance"; "Spinocerebellar ataxia"; "Hippo signalling pathway"; "NOD-like receptor signalling pathway"; "Phosphatidylinositol signalling system"; "Rap1 signalling pathway"; "Platelet activation"; "Yersinia infection"; "Fc gamma R-mediated phagocytosis"; "Human cytomegalovirus infection"; "Inositol phosphate metabolism"; "Thyroid hormone signalling pathway"; "Progesterone-mediated oocyte maturation"; "Oocyte meiosis"; and "Choline metabolism in cancer". Some brain-region-specific differences were furthermore observed for the five PAD isozymes (PADs 1, 2, 3, 4 and 6), with most changes in PAD 2, 3 and 4 when comparing control and PD brain regions. Our findings indicate that PAD-mediated protein citrullination plays roles in metabolic, immune, cell signalling and neurodegenerative disease-related pathways across brain regions in early pre-motor stages of PD, highlighting PADs as targets for future therapeutic avenues.

Comprehensive atlas of mitochondrial distribution and dynamics during oocyte maturation in mouse models

BackgroundOocytes, the largest cells in mammals, harbor numerous mitochondria within their cytoplasm. These highly dynamic organelles are crucial for providing energy resources and serving as central regulators during oogenesis. Mitochondrial dynamics ensure proper energy distribution for various cellular processes involved in oocyte maturation. Previous studies have used alterations in mitochondrial distribution as a biomarker to assess the oocyte health. However, there are discrepancies between studies regarding mitochondrial distribution profiles in healthy oocytes. Consequently, a comprehensive mitochondrial distribution profile in oocytes during maturation has not been fully characterized. Additionally, there is a lack of objective, quantitative methods to evaluate alterations in mitochondrial distribution profiles in oocytes.MethodsThis study aims to provide an in-depth overview of mitochondrial distribution profiles in mouse oocytes at different maturation stages: germinal vesicle (GV) stage, metaphase I (MI), and mature metaphase II (MII). Freshly collected mouse GV, MI and MII oocytes were stained with MitoTracker Red. Confocal microscopy was used to obtain images of mitochondrial distribution profiles in these oocytes. Using the Imaris software, we reconstructed three-dimensional (3D) surface renderings of each oocyte and quantitatively illustrated the mitochondrial distribution profiles.ResultsAt the GV stage, mitochondria in oocytes were evenly distributed throughout the ooplasm. As oocytes progressed to MI and MII stages, mitochondria aggregated and formed clusters, the mean size of mitochondrial clusters and the proportions of clustered mitochondria increased along with the maturation of oocytes.ConclusionsOur findings reveal that mitochondria in mouse oocytes are highly dynamic, undergoing significant reorganizations during oocyte maturation. We for the first time provided comprehensive mitochondrial distribution profiles in mouse oocytes at the GV, MI and MII stages. These mitochondrial distribution profiles were further quantitatively evaluated. Our methods provide an objective and standardized approach for evaluating alterations in mitochondrial dynamics, which can be used as biomarkers to monitor oocyte conditions during maturation.

An integrated approach to the preservation of reproductive material in patients with oncological pathology

Background. Every year, the number of patients who face cancer without having time to realize their reproductive function increases. In view of this, there is a growing need to develop and improve various ways to preserve fertility in this category of patients. The most common techniques are in vitro maturation of oocytes and controlled ovarian stimulation followed by vitrification of oocytes and embryos. At the same time, transvaginal puncture (TVP) has a risk of developing complications such as bleeding or an infectious process. Disorders of the vaginal microflora also increase the likelihood of inflammatory diseases. In this regard, the correction of vaginal dysbiosis is an integral part of the protocols of assisted reproductive technologies before the TVP. Aim. Development of an integrated approach to the preservation of reproductive material in patients with oncological pathology. Materials and methods. A prospective randomized study of 39 women with an identified oncological process and bacterial vaginosis was conducted. The patients were divided into 2 groups: oral probiotic was added to clindamycin therapy in group 1, and vaginal probiotic in group 2. The ovarian reserve was examined for everyone, the qualitative composition of the vaginal microflora was determined, pH-metry was performed and related specialists were consulted if necessary. Results. The patients are comparable in age and ovarian reserve. When using an oral probiotic, an improvement in the qualitative composition of the microflora was noted due to a decrease in opportunistic flora (Gardnerella vaginalis) and an increase in the number of lactobacilli. The vaginal probiotic showed comparable results, but the recurrence rate was 28%, while in group 1 it was 18%. It was noted that when taking Enterolactis Duo, the symptoms associated with chemotherapy treatment decrease. During the study, 396 oocytes were obtained, of which 212 are suitable for vitrification and fertilization. Conclusion. Currently, the development of oncofertility methods and their improvement remain one of the urgent problems. Taking an oral probiotic helps to normalize the vaginal microflora, neutralize the risks of infectious complications in TVP, reduce the likelihood of recurrence of dysbiosis and the development of adverse events associated with chemotherapy. The use of ovulation stimulation demonstrates higher rates compared to in vitro maturation. However, a combination of these procedures can be used to increase the amount of material obtained, which is subsequently used in assisted reproductive technology protocols.

A Significant Correlation of Glutamine and Interlukin-6 with Pregnancy Rate in Women Undergoing ICSI

Background: The composition of follicular fluid (FF) is significantly influenced by metabolic factors, and the analyses of metabolites in FF could reveal the correlation between metabolites and oocyte quality, embryo development, and pregnancy outcome. FF provides nutrients and growth factors that promote oocyte growth, development, and maturation. Objective: To investigate the relationship between serum and FF glutamine and FF IL-6 levels and their influence on the pregnancy rate in women who are undergoing an ICSI treatment cycle. Materials and Methods: A prospective cross-sectional study was performed on 90 women aged 20- 44 years who underwent ICSI treatment from July 2023 to February 2024. Serum and follicular fluid collected on the day of oocyte pick-up were used as biological material. The embryological laboratory examined the retrieved follicular fluid and collected oocytes using stereomicroscopy. ELISA analysed serum, FF glutamine and FF IL-6. The ICSI method was utilized for fertilization. The pregnancy test is done by measuring serum BHCG. Statistical data processing was conducted using the software package SPSS 23. Results: There was a highly significant correlation between FF glutamine and FF IL-6 (p &lt; 0.001) and a positive correlation between FF glutamine and FF IL-6 with pregnancy rate ( p &lt; 0.001) (p &lt; 0.001 ). Conclusion The correlation of FF glutamine and FF IL-6 affects the pregnancy rate in women undergoing ICSI. FF glutamine and FF IL-6 can be considered predictors for pregnancy while serum glutamine has no significance.

PRP Influences Maturation and Fertilisation of Immature Mouse Oocytes.

In vitro maturation (IVM) of immature oocytes is a valuable method to enhance the rate of mature oocytes available for fertilisation. In the current study, platelet-rich plasma (PRP) was employed in IVM medium of immature oocytes. Harvested germinal vesicle stage oocytes with cumulus cells from female mature BALB/c mice divided into two groups of control and experiment. In the experimental group, GV oocytes matured in the IVM medium supplemented with 5% PRP, while in the control group, GV oocytes matured in the IVM medium without PRP. The percentage of GV, MI, MII and degenerated oocytes, zona pellucida thickness, perivitelline space size, diameter of mature oocytes, gene expression of apoptosis-related factors and subsequent development of matured oocytes were assessed. The PRP group displayed significantly improved outcomes in various parameters, including a higher proportion of MII and fertilised oocytes, cleavage and blastocyst embryos, compared to the control group. Moreover, the thickness of the zona pellucida was significantly lower in the PRP group than in the control group (p < 0.05). Furthermore, the PRP group demonstrated a significant decrease in the expression of transcripts associated with apoptosis (Bax and caspase-3); however, in the PRP group, a substantial increase in the expression of Bcl2l1, an apoptosis inhibitor, was observed when compared to the control group (p < 0.05). In conclusion, addition of PRP to the IVM culture media significantly increased oocyte maturation rate, leading to improved fertilisation and subsequent embryonic development. This enhancement highlights the positive influence of PRP on overall invitro maturation efficiency and early embryonic stages.

Epigenetic Modifications Are Involved in Transgenerational Inheritance of Cadmium Reproductive Toxicity in Mouse Oocytes

Maternal cadmium exposure during pregnancy has been demonstrated to have detrimental effects on offspring development. However, the impact of maternal cadmium exposure on offspring oocytes remains largely unknown, and the underlying mechanisms are not fully understood. In this study, we found that maternal cadmium exposure during pregnancy resulted in selective alteration in epigenetic modifications of mouse oocytes in offspring, including a decrease in H3K4me2 and H4K12ac, as well as an increase in DNA methylation of H19. Although ROS levels and mitochondrial activity remain at normal levels, the DNA damage marker γH2AX was significantly increased and the DNA repair marker DNA-PKcs was remarkably decreased in offspring oocytes from maternal cadmium exposure. These alterations are responsible for the decrease in the quality of mouse oocytes in offspring induced by maternal cadmium exposure. As a result, the meiotic maturation of oocytes and subsequent early embryonic development are influenced by maternal cadmium exposure. RNA-seq results showed that maternal cadmium exposure elicits modifications in the expression of genes associated with metabolism, signal transduction, and endocrine regulation in offspring ovaries, which also contribute to the disorders of oocyte maturation and failures in early embryonic development. Our research provides direct evidence of transgenerational epigenetic inheritance of cadmium reproductive toxicity in mouse germ cells.

Construction and validation of a histone-related gene signature for the diagnosis of endometriosis.

Endometriosis is a common chronic disease in childbearing women and a major cause of infertility. Our study aimed to identify and validate a novel gene signature for diagnosing endometriosis based on histone-related genes (HRGs), and to investigate their biological functions in endometriosis. RNA sequence data were downloaded from the Gene Expression Omnibus database, and HRGs were retrieved from the GeneCards database. We identified differentially expressed genes using the limma package, and constructed a diagnostic model using the rms package. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses were performed for visualization, annotation, and integrated discovery. Subsequently, we validated the model using the recall and decision curve analysis (DCA). Additionally, we analyzed the immune microenvironment features using CIBERSORT. A total of 18 differentially expressed HRGs were identified in patients with endometriosis compared with controls. GO and KEGG enrichment was mainly in spindle organization, positive regulation of the cell cycle process, progesterone-mediated oocyte maturation, and cellular senescence and cell cycle. We obtained a signature of four HRGs (JUNB, FRY, LMNB1, and SPAG1). DCA revealed that the diagnostic model benefits patients with endometriosis, regardless of the incidence. CIBERSORT analysis showed that the number of plasma cells increased significantly in endometriosis samples from all four datasets. Our findings provide novel insights into the function of HRGs in the development of endometriosis and identify a new signature of four HRGs that may serve as valuable diagnostic markers and therapeutic targets for this disease.

Effect of Gossypol on Gene Expression in Swine Granulosa Cells.

Gossypol (GP), a polyphenolic compound in cottonseed, has notable effects on female reproduction and the respiratory system in pigs. This study aimed to discern the alterations in gene expression within swine granulosa cells (GCs) when treated with two concentrations of GP (6.25 and 12.5 µM) for 72 h, in vitro. The analysis revealed significant changes in the expression of numerous genes in the GP-treated groups. A Gene Ontology analysis highlighted that the differentially expressed genes (DEGs) primarily pertained to processes such as the mitotic cell cycle, chromosome organization, centromeric region, and protein binding. Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated distinct impacts on various pathways in response to different GP concentrations. Specifically, in the GP6.25 group, pathways related to the cycle oocyte meiosis, progesterone-mediated oocyte maturation, and p53 signaling were prominently affected. Meanwhile, in the GP12.5 group, pathways associated with PI3K-Akt signaling, focal adhesion, HIF-1 signaling, cell cycle, and ECM-receptor interaction showed significant alterations. Notably, genes linked to female reproductive function (CDK1, CCNB1, CPEB1, MMP3), cellular component organization (BIRC5, CYP1A1, TGFB3, COL1A2), and oxidation-reduction processes (PRDX6, MGST1, SOD3) exhibited differential expression in GP-treated groups. These findings offer valuable insights into the changes in GC gene expression in pigs exposed to GP.

Novel imaging and biophysical approaches to study tissue hydraulics in mammalian folliculogenesis

AbstractA key developmental stage in mammalian folliculogenesis is the formation of a fluid-filled lumen (antrum) prior to ovulation. While it has long been speculated that the follicular fluid is essential for oocyte maturation and ovulation, little is known about the morphogenesis and the mechanisms driving the antrum formation and ovulation, potentially due to challenges in imaging tissue dynamics in large tissues. Misregulation of such processes leads to anovulation, a hallmark of infertility in ageing and diseases such as the polycystic ovary syndrome (PCOS). In this review, we discuss recent advances in deep tissue imaging techniques, machine learning and theoretical approaches that have been applied to study development and diseases. We propose that an integrative approach combining these techniques is essential for understanding the physics of hydraulics in follicle development and ovarian functions.

Melatonin decreases excessive polyspermy for single oocyte in pigs through the MT2 receptor

Melatonin supplementation during in vitro maturation (IVM) improves porcine oocyte maturation and embryonic development by exerting antioxidative effects. Nevertheless, the mechanism by which melatonin prevents polyspermy after in vitro fertilization (IVF) remains unclear. Here, we examined the effects of melatonin on cytoplasmic maturation and the incidence of polyspermic penetration in porcine oocytes. No statistically significant difference was observed in the rate of first polar body formation between the groups (Control, Melatonin, Melatonin + Luzindole, and Melatonin + 4-P-PDOT). Interestingly, melatonin supplementation significantly improved the cytoplasmic maturation of porcine oocytes by enhancing the normal distribution of organelles (Golgi apparatus, endoplasmic reticulum and mitochondria) and upregulating organelle-related gene expressions (P < 0.05). However, these promotional effects were counteracted by melatonin antagonists, suggesting that melatonin enhances cytoplasmic maturation through its receptors in porcine oocytes. Melatonin supplementation also significantly improved the rate of diploid and blastocyst formation after IVF by promoting the normal distribution of cortical granules (P < 0.05). In conclusion, melatonin supplementation during in vitro maturation of porcine oocyte improves fertilization efficiency and embryonic developmental competence by enhancing cytoplasmic maturation.

In vitro maturation of bovine oocytes: the role of ROS, oxidative stress, and the impact of natural antioxidant supplementation

According to available data in the literature, Brazil has one of the largest cattle herds in the world and is one of the leading embryo producers, with a clear predominance of embryos produced in vitro. These data influence the ongoing pursuit of optimizing the results obtained in IVEP (in vitro embryo production). In this technique, in vitro maturation (IVM) is such a crucial stage that it justifies studies involving components that, when added to the media, can lead to improved cleavage rates and blastocyst development. It is well known that oocyte quality is influenced by oxidative stress, and in this context, the inclusion of antioxidants in the IVM medium may enhance these outcomes. Thus, the present study aimed to review oocyte maturation, the impact of oxidative stress, and the addition of antioxidants, such as Moringa oleifera, to the IVM media.

Gene expression levels in cumulus cells are correlated with developmental competence of bovine oocytes

The generation of mammalian embryos by in vitro culture is hampered by the failure of many of the embryos to develop to the blastocyst stage. This problem occurs even when cumulus–oocyte complexes (COCs) with good morphology are visually selected and used for culture. Because cumulus cells are important for oocyte maturation and subsequent embryo development, here we compared gene expression patterns in cumulus cells of COCs that developed in vitro to the blastocyst stage with those of COCs that failed to develop. Cumulus cells were aspirated from bovine COCs selected for in vitro culture. Oocyte developmental competence was evaluated by screening for cleavage and development to the blastocyst stage. The collected cumulus cells were used to quantify mRNA levels of FSH receptor (FSHR), insulin-like growth factor-1 receptor (IGF-1R), anti-Müllerian hormone (AMH), AMH receptor II (AMHRII), epidermal growth factor receptor (EGFR), estrogen receptor β (ERβ), B cell lymphoma/leukemia-2 associated X (Bax), and cysteine-aspartic acid protease-3 (Caspase-3). We found that the expression levels of FSHR, IGF-1R, AMH, and EGFR were higher in cumulus cells from COCs that developed to blastocysts as compared with those that failed to develop, whereas expression levels of Bax and Caspase-3 were lower in cumulus cells of COCs that matured to the blastocyst stage. Positive correlations were found between FSHR and IGF-1R expression (r = 0.59) and between ERβ and EGFR expression (r = 0.43) in cumulus cells from COCs that developed to the blastocyst stage. Our findings indicate that gene expression levels in cumulus cells are correlated with the developmental competence of bovine oocytes. Measurement of gene expression in cumulus cells therefore offers a non-invasive means of predicting oocyte developmental competence.