Luteolin Orchestrates Porcine Oocyte Meiotic Progression by Maintaining Organelle Dynamics Under Oxidative Stress

Increasing evidence has demonstrated that oxidative stress impairs oocyte maturation, but the underlying mechanisms remain largely unknown. Here, for the first time, we examined the antioxidant role of luteolin in meiotic progression and the underlying mechanisms. Supplementation of 5 μM luteolin increased the rates of first polar body extrusion and blastocyst formation after parthenogenetic activation, and the expression levels of oocyte competence (BMP15 and GDF9)-, mitogen-activated protein kinase (MOS)-, and maturation promoting factor (CDK1 and Cyclin B)-related genes were also improved. Luteolin supplementation decreased intracellular reactive oxygen species levels and increased the expression levels of oxidative stress-related genes (SOD1, SOD2, and CAT). Interestingly, luteolin alleviated defects in cell organelles, including actin filaments, the spindle, mitochondria, the endoplasmic reticulum, and cortical granules, caused by H2O2 exposure. Moreover, luteolin significantly improved the developmental competence of in vitro-fertilized embryos in terms of the cleavage rate, blastocyst formation rate, cell number, cellular survival rate, and gene expression and markedly restored the competencies decreased by H2O2 treatment. These findings revealed that luteolin supplementation during in vitro maturation improves porcine meiotic progression and subsequent embryonic development by protecting various organelle dynamics against oxidative stress, potentially increasing our understanding of the underlying mechanisms governing the relationship between oxidative stress and the meiotic events required for successful oocyte maturation.

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167 DEVELOPMENTAL COMPETENCE OF PORCINE OOCYTES DERIVED FROM SMALL- OR MEDIUM-SIZED FOLLICLES AND DENUDED OF CUMULUS CELLS BEFORE AND DURING IN VITRO MATURATION

Reproduction Fertility and Development ◽

10.1071/rdv29n1ab167 ◽

2017 ◽

Vol 29 (1) ◽

pp. 192

Author(s):

P. Ferré ◽

K. X. Nguyen ◽

T. Wakai ◽

H. Funahashi

Keyword(s):

Oocyte Maturation ◽

In Vitro Maturation ◽

Polar Body ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Cumulus Cells ◽

Developmental Competence ◽

Blastocyst Formation ◽

First Polar Body

This experiment was undertaken to assess the meiotic and developmental competences of oocytes derived from different sized follicles and denuded of cumulus cells 0, 20, and 44 h after the start of culture for in vitro maturation (IVM). Groups of 60 oocyte-cumulus complexes from small- (SF; <3 mm) and medium-sized follicles (MF; 3–6 mm) were cultured for IVM in porcine oocyte medium with 50 μM β-mercaptoethanol supplemented with 1 mM dibutyryl-cyclic adenosine monophosphate, 10 IU mL−1 of eCG, and 10 IU mL−1 of hCG for 20 h at 39°C and 5% CO2 in air. Then, after washing, they continued culture in fresh β-mercaptoethanol without dibutyryl-cyclic adenosine monophosphate and gonadotropins under the same conditions for another 24 h. At 0, 20, and 44 h of IVM, cumulus cells were removed with 0.1% (wt/vol) hyaluronidase and the denuded oocytes continued IVM culture following the protocol. Mature oocytes with the first polar body were selected, parthenogenetically activated with a single electrical pulse (DC: 1.2 kV/cm, 30 µs), incubated with 4% (wt/vol) BSA and 5 μM cytochalasin B for 4 h, and cultured in porcine zygote medium for 5 days. Cleavage and blastocyst formation rates were observed on Day 2 and 5, respectively. Blastocysts were stained with 4’,6-diamidino-2-phenylindole for cell count assessment. The experiment was replicated 5 times and analysed with a 1- or 2-way ANOVA. If P < 0.05 in ANOVA, a Tukey multiple comparisons test was performed. Regardless of the time of cumulus cell removal, oocytes from MF had significantly higher in rates of maturation, cleavage, and blastocyst rates, as compared with those from SF, whereas there were no significant differences in the cell number of blastocysts between SF and MF (32 v. 34 cells, respectively). When oocytes were denuded before IVM culture, rates of oocyte maturation (37.6% in SF and 50.8% in MF), and blastocyst formation (2.7% in SF and 27.3% in MF) were significantly lower than controls (51.2% in SF and 76% in MF; 25.8% in SF and 48.5% in MF, respectively). When oocytes were denuded 20 h after the start of IVM, oocyte maturation rates were significantly increased (64.1% in SF and 82.5% in MF) as compared with controls, whereas no significant differences were observed in cleavage and blastocyst formation rates in comparison with controls. These results conclude that removing cumulus cells from oocyte-cumulus complexes 20 h after the start of IVM improves the meiotic competence of oocytes derived from both SF and MF, without any reduction of developmental competence of the oocytes following parthenogenetical activation.

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Folic acid facilitates in vitro maturation of mouse and Xenopus laevis oocytes

British Journal Of Nutrition ◽

10.1017/s0007114512003248 ◽

2012 ◽

Vol 109 (8) ◽

pp. 1389-1395 ◽

Cited By ~ 6

Author(s):

Xiaoli Huang ◽

Shu Gao ◽

Wei Xia ◽

Shaoying Hou ◽

Kun Wu

Keyword(s):

Folic Acid ◽

Oocyte Maturation ◽

Polar Body ◽

Water Soluble ◽

Mitogen Activated Protein Kinase ◽

Xenopus Laevis Oocytes ◽

Cortical Granules ◽

Germinal Vesicle Breakdown ◽

First Polar Body

The water-soluble B vitamins, folate and folic acid, play an important role in reproductive health, but little is known about the effects of folic acid on infertility. The present study tested the hypothesis that folic acid affects oocyte maturation, a possible cause of female infertility. We have studied the in vitro maturation of mouse and Xenopus oocytes. Hypoxanthine (Hx) was used as an inhibitor of mouse oocyte maturation to mimic in vivo conditions by maintaining high levels of cyclic-AMP. The frequency of first polar body (PB1) formation and germinal vesicle breakdown (GVBD) in mouse oocytes was decreased by Hx. This effect was counteracted by folic acid added to the medium. PB1 extrusion and GVBD percentages rose to 27·7 and 40·0 % from 12·8 and 19·9 %, respectively, by exposure to 500 μm-folic acid. Folic acid also restored the spindle configuration, which had been elongated by Hx, as well as normalising the distribution of cortical granules (CG). In folic acid-treated Xenopus eggs, extracellular signal-regulated kinase 1 was phosphorylated, cyclin B2 and Mos were up-regulated and the frequency of GVBD was accelerated. Taken together, the findings suggest that folic acid facilitates oocyte maturation by altering the expression and phosphorylation of proteins involved in M-phase-promoting factor and mitogen-activated protein kinase pathways, as well as causing changes in spindle configuration and CG migration.

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174 EFFECT OF HUMAN ENDOTHELIAL PROGENITOR CELLS ON IN VITRO MATURATION OF PORCINE OOCYTES AND PARTHENOGENETIC EMBRYO DEVELOPMENT COMPETENCE

Reproduction Fertility and Development ◽

10.1071/rdv29n1ab174 ◽

2017 ◽

Vol 29 (1) ◽

pp. 195

Author(s):

S. H. Lee ◽

H. J. Oh ◽

M. J. Kim ◽

G. A. Kim ◽

E. M. N. Setyawan ◽

...

Keyword(s):

Growth Factor ◽

Embryo Development ◽

Oocyte Maturation ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Polar Body ◽

Blastocyst Formation ◽

First Polar Body ◽

Significant Difference

In oocyte maturation, hepatocyte growth factor and vascular endothelial growth factor (VEGF) contribute to promote granulosa cell proliferation and cumulus cell expansion. It is well known that human endothelial progenitor cells (hEPC), which are isolated from monocytes and macrophages, secrete a variety of growth factors, such as hepatocyte growth factor and VEGF, and improve the process of angiogenesis. Therefore, the aim of this study was to investigate the effects of hEPC on in vitro oocyte maturation and subsequent embryo development in pigs. To isolate and culture hEPC, human peripheral blood sample was collected from a healthy donor and peripheral blood mononuclear cells were separated. The peripheral blood mononuclear cells were seeded into flask with defined Keratinocyte-SFM-based medium and incubated at 37°C, 5% CO2. The hEPC were cultured and cryopreserved until use for co-culturing with porcine oocytes obtained from a local slaughterhouse ovaries. Cumulus-oocyte complexes were randomly cultured in 2 groups; 1) co-culturing with hEPC and 2) culturing without hEPC. Cumulus-oocyte complexes were cultured in the in vitro maturation (IVM) medium containing TCM-199 supplemented with 0.57 mM cysteine, 0.91 mM sodium pyruvate, 5 μL mL−1 of insulin-transferrin-selenium solution 100X (Invitrogen, Seoul, South Korea), 10% porcine follicular fluid, 10 IU mL−1 of eCG, and 10 IU mL−1 of hCG. After IVM, the first polar body extrusion was observed under the microscope. To evaluate embryo development competence, the matured oocytes were activated with electrical stimulus and cultured in porcine zygote medium-5 for 7 days. The cleavage and blastocyst formation rates were observed on Day 2 and 7, respectively. Also, blastocysts were stained with Hoechst 33342 and total blastocyst cell numbers were evaluated under a fluorescence microscope. As a result, the oocyte maturation rate or first polar body extrusion rate of the hEPC co-culture group (90.06 ± 0.75) was significantly higher than the control group (90.06 ± 0.75 v. 85.79 ± 0.59; P < 0.05). There was no significant difference between the hEPC co-cultured and the control groups in cleavage rate. However, a significant difference in blastocyst formation rate was observed between the hEPC co-cultured and the control groups (28.45 ± 4.92 v. 15.87 ± 2.27; P < 0.05), whereas total blastocyst cell numbers did not show significant difference between the 2 groups. The all data were analysed by unpaired t-test using GraphPad Prism 5.0 (GraphPad Software Inc., La Jolla, CA, USA). Values are means ± standard error of mean. In conclusion, the results in the present study demonstrated that co-culturing with hEPC improved the in vitro oocyte maturation and blastocyst formation rate. Also, we are underway in analysing the concentration of VEGF families in the hEPC co-culture medium after IVM. For further study, we will analyse the genes of the VEGF signaling pathway in the cumulus cells and matured oocytes derived from the 2 groups. This research was supported by Nature Cell (#550-20150030), global PH.D Fellowship Program through NRF funded by the Ministry of Education (NRF-20142A1021187), and Research Institute for Veterinary Science, the BK21 plus program.

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H1foo is essential for in vitro meiotic maturation of bovine oocytes

Zygote ◽

10.1017/s0967199414000021 ◽

2014 ◽

Vol 23 (3) ◽

pp. 416-425 ◽

Cited By ~ 13

Author(s):

Yan Yun ◽

Peng An ◽

Jing Ning ◽

Gui-Ming Zhao ◽

Wen-Lin Yang ◽

...

Keyword(s):

Oocyte Maturation ◽

Polar Body ◽

Linker Histone ◽

Meiotic Maturation ◽

Control Group ◽

Bovine Oocyte ◽

First Polar Body ◽

Effective Sirnas ◽

Bovine Oocytes

SummaryOocyte-specific linker histone, H1foo, is localized on the oocyte chromosomes during the process of meiotic maturation, and is essential for mouse oocyte maturation. Bovine H1foo has been identified, and its expression profile throughout oocyte maturation and early embryo development has been established. However, it has not been confirmed if H1foo is indispensable during bovine oocyte maturation. Effective siRNAs against H1foo were screened in HeLa cells, and then siRNA was microinjected into bovine oocytes to down-regulate H1foo expression. H1foo overexpression was achieved via mRNA injection. Reverse transcription polymerase chain reaction (RT-PCR) results indicated that H1foo was up-regulated by 200% and down-regulated by 70%. Based on the first polar body extrusion (PB1E) rate, H1foo overexpression apparently promoted meiotic progression. The knockdown of H1foo significantly impaired bovine oocyte maturation compared with H1foo overexpression and control groups (H1foo overexpression = 88.7%, H1foo siRNA = 41.2%, control = 71.2%; P < 0.05). This decrease can be rescued by co-injection of a modified H1foo mRNA that has escaped from the siRNA target. However, the H1e (somatic linker histone) overexpression had no effect on PB1E rate when compared with the control group. Therefore we concluded that H1foo is essential for bovine oocyte maturation and its overexpression stimulates the process.

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Proline-rich tyrosine kinase2 is involved in F-actin organization during in vitro maturation of rat oocyte

Reproduction ◽

10.1530/rep.1.01212 ◽

2006 ◽

Vol 132 (6) ◽

pp. 859-867 ◽

Cited By ~ 13

Author(s):

Xiao-Qian Meng ◽

Ke-Gang Zheng ◽

Yong Yang ◽

Man-Xi Jiang ◽

Yan-Ling Zhang ◽

...

Keyword(s):

Oocyte Maturation ◽

Actin Filaments ◽

Laser Scanning ◽

Polar Body ◽

Laser Scanning Microscopy ◽

Meiotic Spindle ◽

Confocal Laser ◽

Cell Cortex ◽

First Polar Body

Microfilaments (actin filaments) regulate various dynamic events during meiotic maturation. Relatively, little is known about the regulation of microfilament organization in mammalian oocytes. Proline-rich tyrosine kinase2 (Pyk2), a protein tyrosine kinase related to focal adhesion kinase (FAK) is essential in actin filaments organization. The present study was to examine the expression and localization of Pyk2, and in particular, its function during rat oocyte maturation. For the first time, by using Western blot and confocal laser scanning microscopy, we detected the expression of Pyk2 in rat oocytes and found that Pyk2 and Try402 phospho-Pyk2 were localized uniformly at the cell cortex and surrounded the germinal vesicle (GV) or the condensed chromosomes at the GV stage or after GV breakdown. At the metaphase and the beginning of anaphase, Pyk2 distributed asymmetrically both in the ooplasm and the cortex with a marked staining associated with the chromosomes and the region overlying the meiotic spindle. At telophase, Pyk2 was observed in the cleavage furrows in addition to its cortex and cytoplasm localization. The dynamics of Pyk2 were similar to that of F-actin, and this kinase was found to co-localize with microfilaments in several developmental stages during rat oocyte maturation. Microinjection of Pyk2 antibody demolished the microfilaments assembly and also inhibited the first polar body (PB1) emission. These findings suggest an important role of Pyk2 for rat oocyte maturation by regulating the organization of actin filaments.

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311EFFECT OF OOCYTE MATURATION MEDIA ON THE SPEED OF MEIOTIC PROGRESSION AND BLASTOCYST DEVELOPMENT OF BOVINE EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab311 ◽

2004 ◽

Vol 16 (2) ◽

pp. 275

Author(s):

D. Fischer ◽

J. Bordignon ◽

C. Robert ◽

D. Betts

Keyword(s):

Embryo Development ◽

Oocyte Maturation ◽

Immunofluorescence Microscopy ◽

Chromosomal Abnormalities ◽

Culture Media ◽

Blastocyst Formation ◽

Blastocyst Development ◽

Nuclear Maturation ◽

Meiotic Progression

Environment is crucial for in vitro development of gametes and embryos. The recent progression of culture media towards defined conditions brought to surface the impact of different medium supplements on oocyte and embryo development. In this work we evaluate the effect of various oocyte culture media on bovine oocyte maturation and subsequent embryo development. Bovine cumulus-oocyte complexes were recovered from slaughterhouse ovaries and matured in vitro in either TCM-199 (Gibco) or SOF (Synthetic Oviduct Fluid) media supplemented with BSA (fatty acid-free) or serum (fetal bovine serum). Oocytes from each treatment group were denuded and fixed at 18, 20, 22, 24, 26 and 28h post-maturation (p.m.). Oocyte meiotic progression was monitored in each of the groups (n=28–40 oocytes/group) by immunofluorescence microscopy of chromatin. Oocytes matured in SOF showed a slower rate of meiotic progression when compared to the other groups, with the highest percentage of oocytes reaching the MII stage by 28h p.m. (60.71% SOF-BSA, 71.43% SOF-Serum). The fastest developmental rate was observed in oocytes matured in TCM-serum (77.15% at 24h p.m.) followed by oocytes matured in TCM-BSA (74.29% at 26h p.m.). In order to evaluate the effect of nuclear maturation on chromosome segregation, chromosomal organization of MII oocytes was evaluated by immunofluorescence microscopy within each media group (n=26–31 oocytes/group) at 18, 22 and 26h p.m.. No chromosomal abnormalities were found at 18h p.m.. Both media supplemented with BSA induced lower frequencies of chromosomal abnormalities (0 to 3.23%) and (3.57 to 7.69%) for SOF and TCM, respectively, when compared to their serum-supplemented counterparts (7.14 to 11.54%) and (10 to 10.71%) for SOF and TCM, respectively at 22 and 26h p.m.. Remarkably, the maturation medium and its supplements influenced the speed of blastocyst development. For this experiment, oocytes were matured in TCM-BSA, TCM-Serum, SOF-BSA or SOF-serum, fertilized in vitro in a TALP-base media supplemented with BSA and cultured in SOF-BSA. Blastocyst development was assessed at 7, 8 and 9 days of culture. Cleavage rates were similar between the groups (84–90%), whereas development rates to blastocyst stage varied among treatment groups. Maturation in SOF-BSA induced a delay in blastocyst formation that reached its highest percentage only on day 9 of culture (30.8%); moreover, blastocyst development was carried over until Day 12. When oocytes were matured in the presence of serum, the number of blastocysts did not increase after Day 8 of culture (26.6%, TCM-serum). These results provide evidence of a severe impact of oocyte culture media on the nuclear maturation of oocytes and their subsequent embryonic development after IVF. Moreover, the difference in the rate of oocyte maturation and blastocyst formation emphasizes the necessity for reviewing and adapting current protocols to new systems such as SOF-BSA. [Research funded by NSERC and OMAF of Canada.]

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Ultrastructure of in vitro oocyte maturation in buffalo (Bubalus bubalis)

Zygote ◽

10.1017/s0967199409990335 ◽

2010 ◽

Vol 18 (4) ◽

pp. 309-314 ◽

Cited By ~ 8

Author(s):

Rafael Gianella Mondadori ◽

Tiago Rollemberg Santin ◽

Andrei Antonioni Guedes Fidelis ◽

Khesller Patrícia Olázia Name ◽

Juliana Souza da Silva ◽

...

Keyword(s):

Polar Body ◽

Bubalus Bubalis ◽

Ultrastructural Changes ◽

Oocyte Nucleus ◽

Cortical Granules ◽

Immature Oocytes ◽

Transmission Electron ◽

High Lipid ◽

First Polar Body

SummaryThe objective of the present study was to describe ultrastructural changes in the nucleus and cytoplasmic organelles during in vitro maturation (IVM) of buffalo cumulus–oocyte complexes (COCs). The structures were collected by ovum pick-up (OPU). Some COCs, removed from maturation medium at 0, 6, 12, 18 and 24 h, were processed for transmission electron microscopy. The average number of COCs collected by OPU/animal/session was 6.4, and 44% of them were viable. Immature oocytes had a peripherally located nucleus, Golgi complex and mitochondrial clusters, as well as a large number of coalescent lipid vacuoles. After 6 h of IVM, the oocyte nucleus morphology changed from round to a flatter shape, and the granulosa cells (GC) lost most of their contact with zona pellucida (ZP). At 12 h the first polar body was extruded and the aspect of lipid droplet changed to dark, probably denoting lipid oxidation. Cortical granules were clearly visible at 18 h of maturation, always located along the oocyte periphery. At 24 h of IVM the number of cortical granules increased. Ultrastructure studies revealed that: (1) immature oocytes have a high lipid content; (2) the perivitelline space (PS) increases during IVM; (3) Golgi complexes and mitochondrial clusters migrate to oocyte periphery during IVM; (4) 6 h of IVM are enough to lose contact between GC and ZP; (5) the oocyte lipid droplets’ appearance changes between 6 and 12 h of IVM.

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Grape Seed Proanthocyanidin Ameliorates FB1-Induced Meiotic Defects in Porcine Oocytes

Toxins ◽

10.3390/toxins13120841 ◽

2021 ◽

Vol 13 (12) ◽

pp. 841

Author(s):

Wenhui Li ◽

Yijing He ◽

Hongyu Zhao ◽

Lei Peng ◽

Jia Li ◽

...

Keyword(s):

Oxidative Stress ◽

Polar Body ◽

Grape Seed ◽

Ros Generation ◽

Mrna Levels ◽

Blastocyst Development ◽

Cleavage Rate ◽

First Polar Body ◽

Grape Seed Proanthocyanidin

Fumonisin B1 (FB1), as the most prevalent and toxic fumonisin, poses a health threat to humans and animals. The cytotoxicity of FB1 is closely related to oxidative stress and apoptosis. The purpose of this study is to explore whether Grape seed proanthocyanidin (GSP), a natural antioxidant, could alleviate the meiotic maturation defects of oocytes caused by FB1 exposure. Porcine cumulus oocyte complexes (COCs) were treated with 30 μM FB1 alone or cotreated with 100, 200 and 300 μM GSP during in vitro maturation for 44 h. The results show that 200 μM GSP cotreatment observably ameliorated the toxic effects of FB1 exposure, showing to be promoting first polar body extrusion and improving the subsequent cleavage rate and blastocyst development rate. Moreover, 200 μM GSP cotreatment restored cell cycle progression, reduced the proportion of aberrant spindles, improved actin distribution and protected mitochondrial function in FB1-exposed oocytes. Furthermore, reactive oxygen species (ROS) generation was significantly decreased and the mRNA levels of CAT, SOD2 and GSH-PX were obviously increased in the 200 μM GSP cotreatment group. Notably, the incidence of early apoptosis and autophagy level were also significantly decreased after GSP cotreatment and the mRNA expression levels of BAX, CASPASE3, LC3 and ATG5 were markedly decreased, whereas BCL2 and mTOR were observably increased in the oocytes after GSP cotreatment. Together, these results indicate that GSP could exert significant preventive effects on FB1-induced oocyte defects by ameliorating oxidative stress through repairing mitochondrial dysfunction.

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Pengaruh urea dalam media maturasi in vitro terhadap tingkat maturasi oosit sapi

Ovozoa Journal of Animal Reproduction ◽

10.20473/ovz.v10i2.2021.46-52 ◽

2021 ◽

Vol 10 (2) ◽

pp. 46

Author(s):

Sepvian Dewi Kurniawati ◽

Suryanie Sarudji ◽

Widjiati Widjiati

Keyword(s):

Oocyte Maturation ◽

Polar Body ◽

Metaphase Plate ◽

Petri Dish ◽

Control Group ◽

Maturation Medium ◽

First Polar Body ◽

Maturation Rate ◽

Follicle Aspiration

This study was aimed to determine the effect of urea in maturation medium on in vitro oocyte maturation rate. The medium used was TCM-199 added with Hepes, NaHCO3, Kanamycin 0.15 IU/mL, PMSG, 0.15 IU/mL hCG, and 10% FBS. Cumulus oocyte complexes (COCs) of cows derived from follicle aspiration were divided into three groups. In control group (P0), the COCs were matured in vitro in a maturation medium without urea addition, meanwhile in the P1 and P2 groups, the medium was added with urea 20 and 40 mg/dL, respectively. Each petri dish contained three drops of maturation medium (300 µl/drops) according to the groups. Microdrops were coated with mineral oil and then incubated in a 5% CO2 incubator, at 39 ˚C with maximum humidity. Aceto-orcein staining was conducted to evaluate the maturation of oocytes based on the achievement of metaphase II phase that is indicated by the presence of metaphase plate and/or first polar body. The result showed that the oocyte maturation rates of P0, P1, and P2 were 51.25, 52.43 (p >0.05), and 46.88 % (p <0.05) respectively. It could be concluded that the presence of urea at 40 mg/dL in maturation medium reduced the percentage of bovine oocyte maturation in vitro.

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UCH-L1 inhibitor LDN-57444 hampers mouse oocyte maturation by regulating oxidative stress and mitochondrial function and reducing ERK1/2 expression

Bioscience Reports ◽

10.1042/bsr20201308 ◽

2020 ◽

Vol 40 (10) ◽

Author(s):

Pan Yuan ◽

Li Zhou ◽

Xiaona Zhang ◽

Lan Yao ◽

Jun Ning ◽

...

Keyword(s):

Oxidative Stress ◽

Embryo Development ◽

Oocyte Maturation ◽

Mitochondrial Function ◽

Molecular Mechanisms ◽

Polar Body ◽

Mouse Oocyte ◽

Body Formation ◽

First Polar Body ◽

Spindle Body

Abstract Oocyte maturation is a prerequisite for successful fertilization and embryo development. Incomplete oocyte maturation can result in infertility. Ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) has been found to be implicated in oocyte maturation and embryo development. However, the cellular and molecular mechanisms of UCH-L1 underlying oocyte maturation have not been fully elucidated. In the present study, we observed that the introduction of UCH-L1 inhibitor LDN-57444 suppressed first polar body extrusion during mouse oocyte maturation. The inhibition of UCH-L1 by LDN-57444 led to the notable increase in reactive oxygen species (ROS) level, conspicuous reduction in glutathione (GSH) content and mitochondrial membrane potential (MMP), and blockade of spindle body formation. As a conclusion, UCH-L1 inhibitor LDN-57444 suppressed mouse oocyte maturation by improving oxidative stress, attenuating mitochondrial function, curbing spindle body formation and down-regulating extracellular signal-related kinases (ERK1/2) expression, providing a deep insight into the cellular and molecular basis of UCH-L1 during mouse oocyte maturation.

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