جستجوی مقالات مرتبط با کلیدواژه "embryonic development" در نشریات گروه "پزشکی"

The purpose of the current study was to reduce the risk of human bias in assessing embryos by automatically annotating embryonic development based on their morphological changes at specified time-points with convolutional neural network (CNN) and artificial intelligence (AI).

Time-lapse videos of embryo development were manually annotated by the embryologist and extracted for use as a supervised dataset, where the data were split into 14 unique classifications based on morphological differences. A compilation of homogeneous pre-trained CNN models obtained via TensorFlow Hub was tested with various hyperparameters on a controlled environment using transfer learning to create a new model. Subsequently, the performances of the AI models in correctly annotating embryo morphologies within the 14 designated classifications were compared with a collection of AI models with different built-in configurations so as to derive a model with the highest accuracy.

Eventually, an AI model with a specific configuration and an accuracy score of 67.68% was obtained, capable of predicting the embryo developmental stages (t1, t2, t3, t4, t5, t6, t7, t8, t9+, tCompaction, tM, tSB, tB, tEB).

Currently, the technology and research of artificial intelligence and machine learning in the medical field have significantly and continuingly progressed in an effort to develop computer-assisted technology which could potentially increase the efficiency and accuracy of medical personnel’s performance. Nonetheless, building AI models with larger data is required to properly increase AI model reliability.

So far, many studies have been conducted on the importance of expressing different genes in humans and zebrafish. In this regard, the expression of OCT4, HOX and SOX genes as influential genes in the embryonic period is very thought-provoking. At different embryonic stages, including morula, middle blastula, gastrula, and segmentation, the expression of these genes is very important in the growth, immunity, tissue repair, and viability of different cells. The aim of this study was to investigate the expression of common genes between humans and zebrafish in the embryonic period and their efficiency in different parts of the body.

Despite a plethora of studies conducted so far, a debate is still unresolved as to whether TLM can identify predictive kinetic biomarkers or algorithms universally applicable. Therefore, this study aimed to elucidate if there is a relationship between kinetic variables and ploidy status of human embryos or blastocyst developmental potential.

For conducting this retrospective cohort study, the normal distribution of data was verified using Kolmogorov-Smirnov test with the Lilliefors’ amendment and the Shapiro-Wilk test. Kinetic variables were expressed as median and quartiles (Q1, Q2, Q3, Q4). Mann-Whitney U-test was used to compare the median values of parameters. Univariate and multiple logistic regression models were used to assess relationship between blastocyst developmental potential or ploidy status and kinetics. Several confounding factors were also assessed.

Blastocyst developmental potential was positively correlated with the t4-t3 interval (s2) (OR=1.417, 95% CI of 1.288-1.560). s2 median value was significantly different between high- and low-quality blastocysts (0.50 and 1.33 hours postinsemination, hpi, respectively; p=0.003). In addition, timing of pronuclear appearance (tPNa) (OR=1.287; 95% CI of 1.131-1.463) had a significant relationship with ploidy changes. The median value of tPNa was statistically different (p=0.03) between euploid and aneuploid blastocysts (Euploid blastocysts=8.9 hpi; aneuploid blastocysts=10.3 hpi).

The present findings are in line with the study hypothesis that kinetic analysis may reveal associations between cleavage patterns and embryo development to the blastocyst stage and ploidy status.

The Hippo pathway plays an important role in embryo development, and separation of trophectoderm (TE) and inner cell mass (ICM) cell lines. Therefore, this study investigated effect of maternal age on activity of Hippo pathway in human embryos.

In this experimental study, the developed up embryos to the blastocyst stage and the embryos whose growth stopped at the morula stage were collected from women aged 20-30 years old (young group, 94 embryos) and >37 years (old group, 89 embryos). Expression of OCT4, SOX2, CDX2, GATA3, YAP genes and the relevant proteins, in the both groups were evaluated using respectively quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunofluorescence methods.

There was no significant difference in the expression level of OCT4, SOX2, CDX2, GATA3 and YAP genes in blastocyst and morula stages, between the two groups. However, SOX2 and CDX2 gene expressions in morula stage embryos of the old group was statistically lower than that of the young group (P=0.007 and P=0.008, respectively). Additionally, in the embryos collected from women with >37 years of age, at the blastocyst stage, phospho-YAP (p-YAP) protein was found to be accumulated in the TE, but it was almost disappeared from the ICM. Additionally, in the old group, contrary to the expectation, YAP protein was expressed in the ICM, rather than TE.

The results of this study showed that YAP and P-YAP among the Hippo signalling pathway may be altered by increasing age.

This study aimed to use a valid mouse model of chronic stress like a maternal separation (MS) to determine the effect of early life chronic stress on oocyte quality and subsequent in vitro embryo development.

This study was based on case-control, interventional, and quantitative applied research. Mice were subjected to 180 minutes of MS stress paradigm at postnatal day (PND) 2–14. Then, corticosterone and serotonin levels were measured in the serum and ovary samples, respectively. In addition, relevant behavioral tests including an elevated plus maze (EPM) and open field test (OFT) were performed for evaluating anxiety-like behaviors at PND 48. Finally, oocyte number, nuclear maturation, reactive oxygen species (ROS) and intracellular glutathione (GSH) levels, as well as in vitro embryo development were evaluated as well.

Our findings showed that MS provokes anxiety-like behavior and increases serum corticosterone concentration (P < 0.05). On the other hand, the number of oocytes (P < 0.001), nuclear maturation (P < 0.05), and the concentration of ovarian serotonin (P < 0.01) decreased following MS. Further, the fertilization (P < 0.001) and blastocyst rate (P < 0.05) significantly decreased in MS mice. Eventually, chronic stress led to a reduction in the level of GSH (P < 0.01) while it increased the level of ROS production (P < 0.001).

Chronic stress through, at least in part, oxidative stress in the oocytes of mice undergoing MS paradigm negatively affected the oocyte competency and embryo development.

Nicotinic acid (niacin) is a broad-spectrum lipid-modifying agent that has potent antioxidant properties and reduces the production of lipid peroxidation.

The purpose of the present study was to investigate the maturation, embryo development and cryo-tolerance merit, and levels of malondialdehyde (MDA), total oxidant status, and total antioxidant capacity following the supplementation of bovine oocytes maturation medium with different concentrations of niacin.

Immature cumulus-oocyte complexes were cultured in tissue culture medium-199 maturation media supplemented with 0, 100, 200, and 400 µM niacin under a standard in vitro culture condition. After 24 hr of culture, the nuclear maturation rate was assessed. Then, two groups of immature cumulus-oocyte complexes were cultured in TCM-199 either with or without 400 µM niacin and evaluated for embryo development. Also, matured cumulus-oocyte complexes in both groups were frozen using a standard vitrification procedure. After vitrification, oocytes were warmed in two steps and evaluated for embryo development. In addition, the level of total antioxidant capacity, total oxidant status, and MDA were measured.

The results indicated that although the treatment with 400 µM niacin increased in vitro nuclear maturation (87.6±5.3), it did not improved the embryo development to the blastocyst stage. Higher cleavage and blastocyst rates were observed in vitrified oocytes that were cultured with supplemented 400 µM niacin compared to the control group (without niacin) (53.6±2.7 and 10.6±1.6 vs. 46.2±4.1 and 6.3±2.4, respectively). Also, the addition of 400 μM niacin to the maturation media could decrease MDA levels after maturation.

Niacin could improve the quality of in vitro embryo production (IVP) embryos and tolerance of bovine oocytes to vitrification.

The expression of miR-302 over the period of early embryogenesis could possibly regulate the maternal transcript clearance. Zygotic transcription activation is mostly related to maternal messages degradation.

In this study, the effects of in-vitro maturation technique (IVM) on the expression of miR-302 in human embryo produced from immature and mature human oocytes (matured in vitro and in vivo, before sperm exposure) obtained from females under gonadotrophin therapy were evaluated for assisted reproduction.

Immature oocytes were cultured in vitro. The injection of oocytes-producing polar bodies was given using fresh sperm. Then, the embryo quality score was assessed in the IVM group compared with the control group. In both the groups, embryos with normal morphology were included in the molecular study. Only one blastomere was removed from three-day embryos and then the embryos were frozen. The expression of miR-302 in embryos was measured through quantitative realtime polymerase chain reaction.

Our data showed a significant reduction of miR-302 expression in the IVM group vs. the control group (p = 0.02). The embryo quality score showed a significant difference between the two groups (p = 0.01).

The present study demonstrated that the IVM process had a negative effect on the expression level of miR-302 in human pre-implantation embryos. Considering the major role of expression miR-302, a decrease in miR-302 expression
could be related to a reduced potential  in the early embryonic development.

Quercetin is a flavonoid with the ability to improve the growth of embryos in vitro, and actinomycin D is an inducer of apoptosis in embryonic cells.

The aim was to evaluate the effect of quercetin on the number of viable and apoptotic cells, the zona pellucida (ZP) thickness and the hatching rate of preimplantation embryos exposed to actinomycin D in mice.

Two-cell embryos were randomly divided into four groups (Control, Quercetin, actinomycin D, and Quercetin actinomycin D group). Blastocysts percentage, hatched blastocysts, and ZP thickness of blastocysts was measured. The number of blastomeres was counted by Hoechst and propidium iodide staining and the apoptotic cells number was counted by TUNEL assay.

The results showed that the use of quercetin significantly improved the growth of embryos compared to the control group (p=0.037). Moreover, quercetin reduced the destructive effects of actinomycin D on the growth of embryos significantly (p=0.026).

quercetin may protect the embryos against actinomycin D so that increases the number of viable cells and decreases the number of apoptotic cells, which can help the expansion of the blastocysts, thinning of the ZP thickness and increasing the hatching rate in mouse embryos.