early embryo
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2024 ◽  
Vol 84 ◽  
A. Azam ◽  
R. Ejaz ◽  
S. Qadeer ◽  
S. Irum ◽  
A. Ul-Husna ◽  

Abstract The objective of the current study was to investigate the synergistic impact of α-Tocopherol and α-Linolenic acid (100 µM) on IVM and IVC of Nili Ravi buffalo oocytes. Oocytes were obtained from the ovaries of slaughtered buffaloes within two hours after slaughter and brought to laboratory. Buffalo cumulus oocyte complexes were placed randomly in the five experimental groups included; GROUP 1: Maturation media (MM) + 100 µM ALA (control), GROUP 2: MM + 100 µM ALA + 50μM α-Tocopherol, GROUP 3: MM + 100 µM ALA + 100μM α-Tocopherol, GROUP 4: MM + 100 µM ALA + 200 μM α-Tocopherol and GROUP 5: MM + 100 µM ALA + 300 μM α-Tocopherol under an atmosphere of 5% CO2 in air at 38.5 °C for 22-24 h. Cumulus expansion and nuclear maturation status was determined (Experiment 1). In experiment 2, oocytes were matured as in experiment 1. The matured oocytes were then fertilized in Tyrode’s Albumin Lactate Pyruvate (TALP) medium for about 20 h and cultured in synthetic oviductal fluid (SOF) medium to determine effect of α-Linolenic acid (100 µM) and α-Tocopherol in IVM medium on IVC of presumptive zygotes. To study the effect of α-Linolenic acid (100 µM) in IVM media and increasing concentration of α-tocopherol in the culture media on early embryo development (Experiment 3), the presumptive zygotes were randomly distributed into the five experimental groups with increasing concentration of α-tocopherol in culture media. Higher percentage of MII stage oocytes in experiment 1(65.2±2.0), embryos at morula stage in experiment 2 (30.4±1.5) and experiment 3 (22.2±2.0) were obtained. However, overall results for cumulus cell expansion, maturation of oocyte to MII stage and subsequent embryo development among treatments remain statistically similar (P > 0.05). Supplementation of α-tocopherol in maturation media having α-Linolenic acid and/or in embryo culture media did not further enhance in vitro maturation of oocyte or embryo production.

2022 ◽  
Ninel Miriam Vainshelbaum ◽  
Kristine Salmina ◽  
Bogdan I Gerashchenko ◽  
Marija Lazovska ◽  
Pawel Zayakin ◽  

The Circadian Clock (CC) drives the normal cell cycle and reciprocally regulates telomere elongation. However, it can be deregulated in cancer, embryonic stem cells (ESC) and the early embryo. Here, its role in the resistance of cancer cells to genotoxic treatments was assessed in relation to whole-genome duplication (WGD) and telomere regulation. We first evaluated the DNA damage response of polyploid cancer cells and observed a similar impact on the cell cycle to that seen in ESC - overcoming G1/S, adapting DNA damage checkpoints, tolerating DNA damage, and coupling telomere erosion to accelerated cell senescence, favouring transition by mitotic slippage into the ploidy cycle (reversible polyploidy). Next, we revealed a positive correlation between cancer WGD and deregulation of CC assessed by bioinformatics on 11 primary cancer datasets (rho=0.83; p<0.01). As previously shown, the cancer cells undergoing mitotic slippage cast off telomere fragments with TERT, restore the telomeres by recombination and return their depolyploidised mitotic offspring to TERT-dependent telomere regulation. Through depolyploidisation and the CC "death loop", the telomeres and Hayflick limit count are thus again renewed. This mechanism along with similar inactivity of the CC in early embryos supports a life-cycle (embryonic) concept of cancer.

Sankar Kumar Das ◽  
Krishna Kalita

Background: Male infertility associated with sperm DNA alteration has raised a new issue in assisted reproduction techniques (ARTs).Methods: It was a retrospective analytical study on 250 cases of routine IVF/ICSI performed at Swagat ART Centre from January 2017 to January 2020. We divided the patient according to the sperm DNA fragmentation index (DFI) as normal DFI≤15%, n=95, a moderate DFI≤30%, n=89, and a high DFI group >30%, n=66. Oocytes of each patient were almost equally divided and fertilization method was adopted as half IVF half ICSI or only ICSI in poor quality (oligo, astheno, teratozoospermia or with two or all three defect and compared the fertilization, cleavage, embryo formation, blastocyst formation, pregnancy and early embryo formation rate among these six groups.  Results: Fertilization, cleavage, embryo formation, and clinical pregnancy rates were reported as higher in ≤15% DFI group of both IVF and ICSI-ET (87.3±26.2, 77.7±26.1, 68.2±28.8, 50.8 in IVF and 78.3±17.8, 70.3±31.2, 67.2±28.8, 57.6 respectively). Significant differences (p<0.01) are observed among all six groups. Higher abortion rate is observed in high DFI group of both IVF and ICSI.Conclusions: High sperm DFI causes low blastocyst formation and pregnancy outcome.  Higher abortion rate observed in high DFI group indicated need of further study.

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 248
Benjamin Lacroix ◽  
Julien Dumont

During cell division, the mitotic spindle, a macromolecular structure primarily comprised of microtubules, drives chromosome alignment and partitioning between daughter cells. Mitotic spindles can sense cellular dimensions in order to adapt their length and mass to cell size. This scaling capacity is particularly remarkable during early embryo cleavage when cells divide rapidly in the absence of cell growth, thus leading to a reduction of cell volume at each division. Although mitotic spindle size scaling can occur over an order of magnitude in early embryos, in many species the duration of mitosis is relatively short, constant throughout early development and independent of cell size. Therefore, a key challenge for cells during embryo cleavage is not only to assemble a spindle of proper size, but also to do it in an appropriate time window which is compatible with embryo development. How spatial and temporal scaling of the mitotic spindle is achieved and coordinated with the duration of mitosis remains elusive. In this review, we will focus on the mechanisms that support mitotic spindle spatial and temporal scaling over a wide range of cell sizes and cellular contexts. We will present current models and propose alternative mechanisms allowing cells to spatially and temporally coordinate microtubule and mitotic spindle assembly.

Tan-Trung Nguyen ◽  
Corinne Best ◽  
Sofia Shevtsov ◽  
Michal Zmudjak ◽  
Martine Quadrado ◽  

Mitochondria play key roles in cellular energy metabolism in eukaryotes. Mitochondria of most organisms contain their own genome and specific transcription and translation machineries. The expression of angiosperm mtDNA involves extensive RNA-processing steps, such as RNA trimming, editing, and the splicing of numerous group II-type introns. Pentatricopeptide repeat (PPR) proteins are key players of plant organelle gene expression and RNA metabolism. In the present analysis, we reveal the function of the MITOCHONDRIAL SPLICING FACTOR 2 gene (MISF2, AT3G22670) and show that it encodes a mitochondria-localized PPR protein that is crucial for early embryo-development in Arabidopsis. Molecular characterization of embryo-rescued misf2 plantlets indicates that the splicing of nad2 intron 1 and thus respiratory complex I biogenesis are strongly compromised. Moreover, the molecular function seems conserved between MISF2 protein in Arabidopsis and its orthologous gene (EMP10) in maize, suggesting that the ancestor of MISF2/EMP10 was recruited to function in nad2 processing before the monocot-dicot divergence, ~200 million years ago. These data provide new insights into the function of nuclear-encoded factors in mitochondrial gene expression and respiratory chain biogenesis during plant embryo development.

Animals ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 127
Lorenzo G. T. M. Segabinazzi ◽  
Brandy N. Roberts ◽  
Erik W. Peterson ◽  
Rachael Ambrosia ◽  
Don Bergfelt ◽  

We aimed to characterize early embryo development and changes in corpus luteum (CL) development and progesterone profile in pregnant vs. non-pregnant jennies. Eight jennies were enrolled in the study. In the first two cycles, the jennies were monitored by transrectal ultrasonography and had blood harvested for hormone profile assay. In the third cycle, jennies were bred by a jack of proven fertility. Jennies were then monitored and sampled for up to 30 days of pregnancy. Data were evaluated by random-effects multiple linear regression, and correlations were expressed as Pearson’s correlation coefficient. Progesterone concentration rose rapidly from ovulation (D0) until D7, plateaued until D12–14, then precipitously declined between D14 and 15, remaining low until the next ovulation in non-pregnant cycles. In the pregnant jennies, the progesterone concentration rose to maximal concentrations on D7–11, being higher at this stage than in non-pregnant cycles, then declined gradually up to D30. In all cycles, the volume of the CL increased steadily until D6, when it plateaued in pregnant jennies. For non-pregnant jennies, CL volume decreased slowly from D6 to D11 and then had a faster drop. Uterine tone increased following ovulation, becoming turgid around the day of embryo fixation (D15.0 ± 0.9). An embryonic vesicle (EV) was first detected on D9.3 ± 0.5 (2.4 ± 0.5 mm). The EV remained spherical until D18.6 ± 1.4. The embryo proper was first detected ventrally in the vesicle on D20.8 ± 1.1 and the embryonic heartbeat by D22.0 ± 0.9. The allantoic sac was identified at D24.0 ± 0.9, and at D30, the allantoic sac filled the ventral half of the EV. This study provides evidence that higher cumulative concentrations of progesterone are correlated to size of the EV, and there were changes in the luteal dynamics and progesterone profiles in pregnant vs. non-pregnant jennies.

Yuewen Zhao ◽  
Sydney Vanderkooi ◽  
Frederick W. K. Kan

AbstractDiverse lines of evidence indicate that the mammalian oviduct makes important contributions to the complex process of reproduction other than being simply a conduit for the transport of gametes and embryos. The cumulative synthesis and transport of proteins secreted by oviductal secretory cells into the oviductal lumen create a microenvironment supporting important reproductive events, including sperm capacitation, fertilization, and early embryo development. Among the components that have been identified in the oviductal fluid is a family of glycosylated proteins known collectively as oviduct-specific glycoprotein (OVGP1) or oviductin. OVGP1 has been identified in several mammalian species, including humans. The present review summarizes the work carried out, in various mammalian species, by many research groups revealing the synthesis and secretion of OVGP1, its fate in the female reproductive tract upon secretion by the oviductal epithelium, and its role in modulating biological functions of gametes and embryos. The production and functions of recombinant human OVGP1 and recombinant OVGP1 of other mammalian species are also discussed. Some of the findings obtained with immunocytochemistry will be highlighted in the present review. It is hoped that the findings obtained from recent studies carried out with recombinant OVGP1 from various species will rekindle researchers’ interest in pursuing further the role of the oviductal microenvironment, of which OVGP1 is a major component, in contributing to the successful occurrence of early reproductive events, and the potential use of OVGP1 in improving the current assisted reproductive technology in alleviating infertility.

Elina Aleksejeva ◽  
Natasa Zarovni ◽  
Keerthie Dissanayake ◽  
Kasun Godakumara ◽  
Paola Vigano ◽  

Abstract Mammalian conception involves a multitude of reciprocal interactions via a molecular dialogue between mother and conceptus. Extracellular vesicles (EVs) are secreted membrane-encapsulated particles that mediate cell-to-cell communication in various contexts. EVs, which are present in seminal, follicular, oviductal, and endometrial fluids, as well as in embryo secretions, carry molecular constituents that impact gamete maturation, fertilization, early embryo development, and embryo-maternal communication. The distribution, concentration, and molecular cargo of EVs are regulated by steroid hormones and the health status of the tissue of origin, and thus are influenced by menstrual phase, stage of conception, and the presence of infertility-associated diseases. EVs have been recognized as a novel source of biomarkers and potential reproductive medicine therapeutics, particularly for assisted reproductive technology (ART). There are still many technological and scientific hindrances to be overcome before EVs can be used in clinical diagnostic and therapeutic ART applications. Issues to be resolved include the lack of standardized measurement protocols and an absence of absolute EV quantification technologies. Additionally, clinically suitable and robust EV isolation methods have yet to be developed. In this review, we provide an overview of EV-mediated interactions during the early stages of reproduction from gamete maturation to embryo implantation and then outline the technological progress that must be made for EV applications to be translated to clinical settings.

Ling Zeng ◽  
Jinzhao Zhou ◽  
Yanwei Zhang ◽  
Xiaofei Wang ◽  
Mei Wang ◽  

Cadmium (Cd) is a toxic heavy metal and ubiquitous environmental endocrine disruptor. Previous studies on Cd-induced damage to male fertility mainly focus on the structure and function of testis, including cytoskeleton, blood-testis barrier, and steroidogenesis. Nevertheless, to date, no studies have investigated the effects of Cd exposure on sperm epigenetic inheritance and intergenerational inheritance. In our study, we systematically revealed the changes in sperm tRNA-derived small RNAs (tsRNA) profiles and found that 14 tsRNAs (9 up-regulated and 5 down-regulated) were significantly altered after Cd exposure. Bioinformatics of tsRNA-mRNA-pathway interactions revealed that the altered biological functions mainly were related to ion transmembrane transport, lipid metabolism and cell membrane system. In addition, we focused on two stages of early embryo development and selected two organs to study the impact of these changes on cell membrane system, especially mitochondrion and lysosome, two typical membrane-enclosed organelles. Surprisingly, we found that the content of mitochondrion was significantly decreased in 2-cell stage, whereas remarkably increased in the morula stage. The contents of mitochondrion and lysosome were increased in the testes of 6-day-old offspring and livers of adult offspring, whereas remarkably decreased in the testes of adult offspring. This provides a possible basis to further explore the effects of paternal Cd exposure on offspring health.

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