Embryonic Development Research Articles

Morpho-molecular evaluation for developmental competence of oocytes retrieved through transvaginal ovum pick-up from FSH-stimulated Tharparkar donor cows (Bos indicus).

The study was conducted on indigenous Tharparkar cow (Bos indicus) to evaluate FSH stimulation on follicular attributes, oocyte recovery and morpho-molecular developmental competence parameters concerning oocyte quality. A total of 20 OPU sessions were performed, which included 10 sessions in each FSH stimulated at the dose of 130 µg divided into four sub-doses and non-stimulated. Findings on the size of follicles having ≥6 mm showed a significantly higher, however an opposite trend was observed in the case of smaller sized follicle (<6 mm) between stimulated and non-stimulated respectively. The stimulated cows had a significantly higher number as well as the percentage of oocytes of Grade A, having a diameter ≥120 µm and BCB+VE as compared to the non-stimulated cows. The relative mRNA expression profile of GDF9, BMP15, PCNA and BCL-2 genes was higher and BAX was lower in the FSH-stimulated cow. These results indicated that FSH stimulation before OPU in Bos indicus cows has a significant impact on follicle size, oocyte yield, recovery, and their quality with respect to COC's, diameter and BCB+VE oocytes. Further, a significant increase in the relative mRNA expression levels of GDF9, BMP15 and PCNA genes in the FSH-stimulated group suggests that FSH plays a key role in modulating the expression of these important candidate genes and thus influencing oocyte quality. The higher mRNA expression of BCL-2 genes and concomitantly lower expression of BAX gene in FSH Stimulated cows indicates the protective role of these genes and preventing programmed cell death and thus promoting cell survival, quality and embryo development.

Early Supraspinal Influences on Human Embryonic Posture.

Knowledge of embryonic body posture as a reflection of neurodevelopment is limited. Here, we investigate embryonic body posture, preference, symmetry, and lateralization during periods of rest using virtual reality (VR) and four-dimensional (4D) ultrasound techniques to enhance our knowledge of neurodevelopment. It is hypothesized that lateralization and asymmetry in embryonic posture are absent. Embryos from low-risk pregnancies at 9 weeks gestational age (GA) were analyzed using a 30-min 4D ultrasound and VR techniques. In the middle of an embryonic resting period, the total body posture was determined by combining joint positions. Interindividual and intraindividual postures were analyzed over time to identify posture preferences, asymmetry, and lateralization. Sixteen embryos (N=210 middle frames out of 210 resting periods) displayed 27 different embryonic body postures. Interindividual and intraindividual variations in postures were seen. Asymmetry was noted in upper extremities, whereas lateralization of the head and spine was observed in nine embryos. Intraindividual and interindividual variation in embryonic posture at 9 weeks' GA is seen, suggesting the presence of supraspinal influences on body posture this early. Future interdisciplinary longitudinal studies on embryonic posture may provide further insights into embryonic central nervous system development, contributing to our understanding of embryonic health.

VISTA Enhancer browser: an updated database of tissue-specific developmental enhancers.

Regulatory elements (enhancers) are major drivers of gene expression in mammals and harbor many genetic variants associated with human diseases. Here, we present an updated VISTA Enhancer Browser (https://enhancer.lbl.gov), a database of transgenic enhancer assays conducted in developing mouse embryos in vivo. Since the original publication in 2007, the database grew nearly 20-fold from 250 to over 4500 experiments and currently harbors over 23500 images. The updated database provides structured information on experiments conducted at different stages of embryonic development, including enhancer activities of human pathogenic and synthetic variants and sequences derived from a variety of species. In addition to manually curated results of thousands of individual experiments, the new database also features hundreds of manually curated comparisons between alleles. The VISTA Enhancer Browser provides a crucial resource for study of human genetic variation, gene regulation and developmental biology.

Single-cell RNA transcriptomics in mice reveals embryonic origin of fibrosis due to maternal obesity

Over 40% of pregnant women in the USA are obese which negatively affects fetal development and offspring health. Maternal obesity (MO) leads to fibrotic infiltration in multiple tissues and organs of offspring during their adulthood although the origin and mechanisms are unclear. C57BL/6J female mice were fed a control and high-fat diet to mimic MO condition. Embryonic somatic tissues were obtained at E9.5, E11.5, and E13.5 (equivalent to 6 weeks of human pregnancy) from control (CON) and MO mice for single-cell RNA-sequencing (scRNA-seq). To explore the role of AMP-activated protein kinase (AMPK), AMPK was activated by metformin and A769662, and knocked out in embryonic mesenchymal cells (EMC) using AMPKα1 floxed mice. Using unsupervised clustering, we identified three major cell populations with fibrogenic capacity. Compared to CON, the population of fibrogenic cells increased dramatically (by ∼125%) due to MO, supporting an embryonic origin of fibrosis in the offspring. MO induced inflammatory response and elevated expression of transforming growth factor β (TGFβ) signalling and fibrogenic genes in embryos. MO inhibited AMPK and its activation by metformin and A769662 inhibited TGFβ signalling and fibrogenesis. MO profoundly enhances embryonic fibrogenesis, explaining the origin of fibrosis in the offspring of mothers living with obesity. Our data underscore the importance of early intervention, before 5-6 weeks of pregnancy, in improving embryonic development, and AMPK is an amiable target for suppressing excessive fibrogenesis in MO embryos to assist increasing populations of obese mothers having healthy children. This work was funded by National Institutes of Health Grant R01HD067449.

A quest of Vera M. Danchakoff, a pioneer of stem cell research.

Vera Mikhailovna Danchakova (1877-1950), also written in English as Danchakoff and in German as Dantschakoff, was the first woman to graduate with a PhD in Russia. She was a person of many interests and a strong passion for teaching and social justice that may have interfered with her pioneering stem cell research and cell biology, which was far ahead of its time. Danchakova significantly contributed to the unitarian theory of haematopoiesis along with its founder Alexander A. Maximow. She studied the origin of blood cells, the differentiation of tissues and organs in the process of embryonic development of animals, the formation of germ cells and the effect of hormones on the development of organisms. She discovered the role of stem cells in the laying of new tissues, the proof of the extragonadal origin of primary germ cells in birds and the development of methods for transplanting tissues into live embryos. She has been named 'the mother of stem cells' for her investigations of progenitors of cells.

Behavioural thermoregulation prevents thermal stress in lizard sperm fertility

Global warming is threatening ectotherms, with strong repercussions on their population dynamics. Body temperature in ectotherm reptiles is crucial to perform all their biological functions, which are maximized within a narrow interval. When faced with new or adverse thermal conditions, reptiles will respond with distributional changes, behavioural adjustments to maintain their internal temperature, or by adapting to the new environment, otherwise, extinctions will occur. Higher temperatures may have negative repercussions, for example, shortening periods of activity, affecting embryo development during gestation or decreasing viability of sperm cells in males. Through behavioural thermoregulation, reptiles can compensate for environmental variations (Bogert effect). Furthermore, according to Janzen’s hypothesis, the physiological cost of responding to adverse thermal conditions will be low in species exposed to higher thermal overlap. Here, we analysed the effect of a change in the thermal regime on sperm cell viability in Sceloporus megalepidurus, a small viviparous lizard from central Mexico. We hypothesized that an active thermoregulator inhabiting temperate mountains is able to prevent the effects of thermal change on sperm cell viability. We found that the change in thermal regime did not modify sperm cell viability, nor does it affect the maturation of sperm cells in the epididymis. Our results support the Bogert effect and suggest that, despite the high temperatures and low thermal quality, S. megalepidurus can maintain its body temperature within an optimal range for sperm cell viability.

Anti-Mitotic Activity Of Gumamela (Hibiscus Rosa-Sinensis) Leaf Extract In The Early In-Vitro Development Of Sea Urchin (Tripneustes Gratilla) Embryo

Plant-derived products have played an important role in the development of several clinically useful anticancer agents. Several cancer treatments have been widely used, including surgery, chemotherapy, and radiotherapy. However, no selective cancer therapies exist that can eliminate cancer cells while preserving healthy cells unharmed. This study aims to determine the antimitotic activity of Hibiscus rosa-sinensis leaf extract in the early in-vitro development of sea urchin Tripneustes gratilla embryo. The Hibiscus rosa-sinensis leaves were extracted using ethanol into four different concentrations (0.5%, 1.0%, 1.5%, 2.0%). A Sea urchin bioassay was then performed to determine its antimitotic activity against the Tripneustes gratilla embryo. Phytochemical confirmatory tests were also done to confirm the presence of bioactive compounds. The results of the study showed that Hibiscus rosa-sinensis leaf extracts contained alkaloids, flavonoids, tannins, and saponins. The Sea Urchin Bioassay reveals that the various leaf extract concentrations (0.5%, 1.0%, 1.5%, 2.0%) inhibited antimitotic activity against the early cell development of sea urchin embryo as it had a slower rate of mitotic activity as compared to the negative control. Moreover, the higher concentration of leaf extract 1.5% and 2.0% revealed to have greater antimitotic activity similar to that of the positive control colchicine as data showed it had the least number of embryos developed. This implies that the antimitotic activity of Hibiscus rosa-sinensis leaf extracts is concentration-dependent. An ANOVA test showed that there are significant differences between the various leaf concentrations and control groups in the early cell development of sea urchin embryos in minute intervals.

Three main portal veins: A very rare case of portal vein anomaly

Portal vein (PV) anomalies are rare during embryonic development, with very few cases of duplicated PVs reported. This case reveals a new PV trunk anomaly, where computed tomography venography imaging shows three portal veins. The superior mesenteric vein and inferior mesenteric vein join to form a trunk that divides into two branches: One entering the liver (PV1) and the other ascending to join the splenic vein. The splenic vein then divides into two branches in the neck of the pancreas (PV2 and PV3), both entering the liver. The three PVs vary in thickness and all enter the liver through the first hepatic portal. Understanding the normal structure and anatomy of the PV is important for successful surgical planning. This case involves three main trunks of the PV, which is an extremely rare type of PV duplication anomaly. Reporting this case aims to enhance the awareness and understanding of PV duplication anomalies among clinicians and radiologists.

Unlocking the secrets of Cardiac development and function: the critical role of FHL2.

FHL2 (Four-and-a-half LIM domain protein 2) is a crucial factor involved in cardiac morphogenesis, the process by which the heart develops its complex structure. It is expressed in various tissues during embryonic development, including the developing heart, and has been shown to play important roles in cell proliferation, differentiation, and migration. FHL2 interacts with multiple proteins to regulate cardiac development as a coactivator or a corepressor. It is involved in cardiac specification and determination of cell fate, cardiomyocyte growth, cardiac remodeling, myofibrillogenesis, and the regulation of HERG channels. Targeting FHL2 has therapeutic implications as it could improve cardiac function, control arrhythmias, alleviate heart failure, and maintain cardiac integrity in various pathological conditions. The identification of FHL2 as a signature gene in atrial fibrillation suggests its potential as a diagnostic marker and therapeutic target for this common arrhythmia.

Mechanisms of Bone Morphogenetic Protein 2 in Respiratory Diseases.

Bone morphogenetic protein 2 (BMP2) belongs to the transforming growth factor-β (TGF-β) superfamily and plays an important role in regulating embryonic development, angiogenesis, osteogenic differentiation, tissue homeostasis, and cancer invasion. Increasing studies suggest BMP2 is involved in several respiratory diseases. This study aimed to review the role and mechanisms of BMP2 in respiratory diseases. BMP2 signaling pathway includes the canonical and non-canonical signaling pathway. The canonical signaling pathway is the BMP2-SMAD pathway, and the non-canonical signaling pathway includes mitogen-activated protein kinase (MAPK) pathway and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway. The BMP2 is related to pulmonary hypertension (PH), lung cancer, pulmonary fibrosis (PF), asthma, and chronic obstructive pulmonary disease (COPD). BMP2 inhibits the proliferation of pulmonary artery smooth muscle cells (PASMCs), promotes the apoptosis of PASMCs to reduce pulmonary vascular remodeling in PH, which is closely related to the canonical and non-canonical pathway. In addition, BMP2 stimulates the proliferation and migration of cells to promote the occurrence, colonization, and metastasis of lung cancer through the canonical and the non-canonical pathway. Meanwhile, BMP2 exert anti-fibrotic function in PF through canonical signaling pathway. Moreover, BMP2 inhibits airway inflammation to maintain airway homeostasis in asthma. However, the signaling pathways involved in asthma are poorly understood. BMP2 inhibits the expression of ciliary protein and promotes squamous metaplasia of airway epithelial cells to accelerate the development of COPD. In conclusion, BMP2 may be a therapeutic target for several respiratory diseases.

Histological Analysis of Somatic Embryogenesis from Immature Zygotic Embryo of Wild Banana Musa acuminata ssp. malaccensis

Somatic embryogenesis, a crucial plant regeneration method, has become indispensable for crop improvement, particularly for species reliant on somatic cell manipulation techniques. Optimization of this process necessitates an understanding of the developmental stages involved. This study investigates the histological aspects of somatic embryogenesis in Musa acuminata ssp. malaccensis derived from immature zygotic embryos. Through detailed histological analysis, we aimed to elucidate the morphological changes and cellular organization occurring during the various stages of somatic embryogenesis, from induction, culture proliferation, and somatic embryo development to plantlet conversion. The initial stages of embryogenesis, characterized by nodules, were primarily composed of meristematic cells with high cell division activity. These cells contained tetrad-like structures that could develop into distinct two- and four-celled proembryoids or proembryogenic aggregates. Our histo-anatomical analysis revealed that embryogenic cultures proliferated through multiple pathways simultaneously: somatic embryo budding, proembryo formation, and pro-embryonic mass formation from both internal and peripheral cells. At the stage of somatic embryo development, embryos with a well-defined protoderm layer, containing cells with prominent nuclei and dense cytoplasm, potentially regenerate into plantlets. Furthermore, histological examination revealed the presence of procambium within mature somatic embryos, which subsequently developed into the vascular system of the complete plantlet

Induction and maturation of somatic embryogenesis in mangaba tree a multipurpose Apocynaceae

This study reported the first results of in vitro somatic embryogenesis induction in Hancornia speciosa Gomes (mangaba tree, Apocynaceae). To induce callus, the TC accession leaf and nodal segments were cultivated in culture medium I (Murashige and Skoog; MS salts, putrescine, 45 µM 2,4-dichlorophenoxyacetic acid; 2,4-D and 22.19 µM 6-benzylaminopurine; BA). For the next stage (multiplication), the callus masses were sub-cultured into a culture medium II (MS salts, 22.62 µM 2,4-D and 22.19 µM BA). After 90 days, embryogenic calluses were inoculated to somatic embryo maturation medium culture III (MS salts, polyethylene glycol; PEG (0 and 2%) and BA (44.39 and 66.58 µM). Pro-embryos and somatic embryos in the maturation stage were assessed after 60 days. The rstatix package from R software with non-parametric tests (p &lt; 0.05) were used to analysis data of experiments I and II. The Tukey’s test (p &lt; 0.05) was performed on the data of experiment III. To induce and multiply embryogenic callus, 45 µM 2,4-D and 22.19 µM BA were efficient. More pro- and somatic embryo development were seen in the nodal explant cultured in the presence of 44.39 and 66.58 µM BA and 2% PEG. Putrescine does not promote the embryogenic masses of callus derived from leaf explants in the TC accession. Keywords: Hancornia speciosa Gomes, micropropagation, somatic embryo.

A transcriptome atlas of zygotic and somatic embryogenesis in Norway spruce.

Somatic embryogenesis (SE) is a powerful model system for studying embryo development and an important method for scaling up availability of elite and climate-adapted genetic material of Norway spruce (Picea abies L. Karst). However, there are several steps during the development of the somatic embryo (Sem) that are suboptimal compared to zygotic embryo (Zem) development. These differences are poorly understood and result in substantial yield losses during plant production, which limits cost-effective large-scale production of SE plants. This study presents a comprehensive data resource profiling gene expression during zygotic and somatic embryo development to support studies aiming to advance understanding of gene regulatory programmes controlling embryo development. Transcriptome expression patterns were analysed during zygotic embryogenesis (ZE) in Norway spruce, including separated samples of the female gametophytes and Zem, and at multiple stages during SE. Expression data from eight developmental stages of SE, starting with pro-embryogenic masses (PEMs) up until germination, revealed extensive modulation of the transcriptome between the early and mid-stage maturing embryos and at the transition of desiccated embryos to germination. Comparative analysis of gene expression changes during ZE and SE identified differences in the pattern of gene expression changes and functional enrichment of these provided insight into the associated biological processes. Orthologs of transcription factors known to regulate embryo development in angiosperms were differentially regulated during Zem and Sem development and in the different zygotic embryo tissues, providing clues to the differences in development observed between Zem and Sem. This resource represents the most comprehensive dataset available for exploring embryo development in conifers.

Foxi1 regulates multiple steps of mucociliary development and ionocyte specification through transcriptional and epigenetic mechanisms.

Foxi1 is a master regulator of ionocytes (ISCs / INCs) across species and organs. Two subtypes of ISCs exist, and both α- and β-ISCs regulate pH- and ion-homeostasis in epithelia. Gain and loss of FOXI1 function are associated with human diseases, including Pendred syndrome, male infertility, renal acidosis and cancers. Foxi1 functions were predominantly studied in the context of ISC specification, however, reports indicate additional functions in early and ectodermal development. Here, we re-investigated the functions of Foxi1 in Xenopus laevis embryonic mucociliary epidermis development and found a novel function for Foxi1 in the generation of Notch-ligand expressing mucociliary multipotent progenitors (MPPs). We demonstrate that Foxi1 has multiple concentration-dependent functions: At low levels, Foxi1 confers ectodermal competence through transcriptional and epigenetic mechanisms, while at high levels, Foxi1 induces a multi-step process of ISC specification and differentiation. We further describe how foxi1 expression is affected through auto- and Notch-regulation, how Ubp1 and Dmrt2 regulate ISC subtype differentiation, and how this developmental program affects Notch signaling as well as mucociliary patterning. Together, we reveal novel functions for Foxi1 in Xenopus mucociliary epidermis formation, relevant to our understanding of vertebrate development and human disease.

RAD50 Deficiency and Its Effects on Zebrafish Embryonic Development and DNA Repair Mechanisms

The MRE11-RAD50-NBS1 (MRN) complex is essential in detecting, signaling, and repairing DNA double-strand breaks (DSBs), thus maintaining genomic integrity. Mutations in RAD50 are linked to severe conditions such as microcephaly, mental retardation, and growth retardation in humans. This study investigates the developmental impact of RAD50 protein disruption in zebrafish embryos. Zebrafish embryos were treated with MIRIN (35 µM) to inhibit RAD50 and subsequently exposed to gamma-ray irradiation (15 Gy) to analyze the role of RAD50 in managing DNA damage during embryogenesis. Time-point analysis indicated that inhibiting RAD50 and ATM proteins during early embryonic stages (at 1 hpf) leads to increased embryonic mortality and abnormalities. These adverse effects were exacerbated by irradiation, underscoring the critical role of RAD50 in DNA DSB repair. The study concludes that RAD50 deficiencies can lead to embryonic lethality and human deformities due to the inability of tissues to repair DNA DSBs effectively.

Effects of development and parental care on Hamilton's force of selection.

The force of selection describes the sensitivity of population growth to changes in life history parameters, with a focus usually on the survival probabilities from one age class to the next. Importantly, according to Hamilton the force of selection generally decreases after the onset of reproduction, thereby providing a possible explanation for patterns of senescence. A second characteristic feature is that the force of selection remains constant up to the age of first re- production. This latter observation, however, rests on the assumption that offspring become independent from their parents right after birth. I show here in a minimal model that if offspring are fully reliant on their parents, either during early embryonal development or via parental care at later stages, and during this time prevent their parents from entering a new bout of repro- duction, the force of selection on offspring survival generally increases up until the age at which offspring become independent. This provides a possible explanation for the commonly observed pattern of decreasing mortality during early ontogeny. Further, genes acting during recurrent life stages are observed to experience a heightened force of selection compared to genes that act strictly age-specifically, demonstrating the need to develop a mechanistic understanding of gene activation patterns through which to consider life history evolution.

Notch signaling pathway suppresses mRNA expression of hexokinase 2 under nutrient-poor conditions in U87-MG glioma cells.

Control of nutrient homeostasis plays a central role in cell proliferation/survival during embryonic development and tumor growth. Activation of the Notch signaling pathway, a major contributor to cell-cell interactions, is a potential mechanism for cell adaptation to nutrient-poor conditions. Our previous study also demonstrated that during embryogenesis when nutrients such as glutamine and growth factors are potentially maintained at lower levels, Notch signaling suppresses mRNA expression of hexokinase 2 (hk2), which is a glycolysis-associated gene, in the central nervous system. However, whether and how the genetic regulation of HK2 via Notch signaling contributes to cellular adaptability to nutrient-poor environments remains unknown. In this study, we performed gene expression analysis using a U87-MG human glioma cell line and revealed that under conditions where both glutamine and serum were absent, Notch signaling was activated and HK2 expression was downregulated by Notch signaling. We also found that Notch-mediated HK2 suppression was triggered in a Notch ligand-selective manner. Furthermore, HK2 was shown to inhibit cell proliferation of U87-MG gliomas, which might depend on Notch signaling activity. Together, our findings suggest the involvement of Notch-mediated HK2 suppression in an adaptive mechanism of U87-MG glioma cells to nutrient-poor conditions.

Shifts in embryonic oxygen levels cue heterochrony in limb initiation.

Heterochrony, or the alteration of developmental timing, is an important mechanism of evolutionary change. Avian species display synchronized growth of the forelimbs and hindlimbs, while mammalian species show delayed hindlimb development. We find that mammalian limb heterochrony is evident from the start of limb bud formation, and is associated with heterochronic expression of T-box transcription factors. This heterochronic shift is not due to changes in cis-regulatory sequences controlling T-box gene expression, but unexpectedly, is dependent upon differential oxygen levels to which avian and mammalian embryos are exposed prior to limb initiation, mediated, at least partially, by an NFKB transcription factor, cRel. Together, these results provide mechanistic understanding of an important example of developmental heterochrony and exemplify how the maternal environment regulates timing during embryonic development.

Early embryonic development of the German cockroach Blattella germanica

BackgroundEarly embryogenesis is characterized by dramatic cell proliferation and movement. In most insects, early embryogenesis includes a phase called the uniform blastoderm, during which cells evenly cover the entirety of the egg. However, the embryo of the German cockroach, Blattella germanica, like those of many insects within the super order Polyneoptera, does not have a uniform blastoderm; instead, its first cells condense rapidly at the site of a future germband. We investigated early development in this species in order to understand how early gene expression is or is not conserved in these insect embryos with distinct early cell behaviors.ResultsWe present a detailed time series of nuclear division and distribution from fertilization through germband formation and report patterns of expression for the early patterning genes hunchback, caudal, and twist in order to understand early polarization and mesoderm formation. We show a detailed time course of the spatial expression of two genes involved in the segmentation cascade, hedgehog and even-skipped, and demonstrate two distinct dynamics of the segmentation process.ConclusionsDespite dramatic differences in cell distribution between the blastoderms of many Polyneopteran insects and those of more well-studied developmental models, expression patterns of early patterning genes are mostly similar. Genes associated with axis determination in other insects are activated relatively late and are probably not maternally deposited. The two phases of segmentation—simultaneous and sequential—might indicate a broadly conserved mode of morphological differentiation. The developmental time course we present here should be of value for further investigation into the causes of this distinct blastoderm type.

The NAD+ precursor nicotinamide riboside protects against postovulatory aging in vitro.

Postovulatory aging (POA) of oocytes is clinically significant as it mirrors the degeneration observed in maternally aged oocytes, leading to substantial impairments in oocyte quality and the success rates of artificial reproductive technology (ART). The molecular alterations associated with POA, such as the degeneration of the first polar body, an increase in perivitelline space, reactive oxygen species (ROS) accumulation, energy depletion, and chromosomal and DNA damage, underscore the urgency of finding interventions to mitigate these effects. This study aims to identify whether nicotinamide riboside (NR) can prevent POA during the process of in vitro culture and raise the success rates of ART. Taking advantage of an in vitro postovulatory oocyte aging model, we examined the morphological integrity and NAD+ levels of ovulated mouse MII oocytes after 24h of culturing. Following in vitro fertilization, we assessed the embryonic developmental potential of oocytes affected by POA. Using immunofluorescence and confocal microscopy, we measured the levels of ROS, mitochondrial function, and γH2AX. We also evaluated spindle assembly and chromosome alignment. Additionally, we detected the distribution of cortical granules to assess the metabolic and quality changes in POA oocytes with the supplementation of NR. To further our analysis, quantitative real-time PCR was conducted to measure the mRNA expression levels of antioxidant enzymes Sod1 and Gpx1 in the oocytes. With 200μM NR supplementation during in vitro culture for 24h, the oocytes from POA demonstrated reduced signs of aging-related decline in oocyte quality, including reduced ROS accumulation, improved mitochondrial function, and corrected mis-localization of cortical granules. This improvement in oocyte quality is likely due to the inhibition of oxidative stress via the NAD+/SIRT1 signaling pathway, which also helped to restore normal spindle assembly and chromosome alignment, as well as reduce the elevated levels of γH2AX, thereby potentially enhancing the embryonic development potential. Current research provides evidence that NR is an efficient and safe natural component that prevents the process of POA and is thus a potential ideal antiaging drug for raising the success rates of ART in clinical practice.