scholarly journals The fate and rôle of macromolecules synthesized during mammalian oocyte meiotic maturation. II. — Autoradiographic topography of (3H)-fucose incorporation in pig oocytes cultured in vitro

1982 ◽  
Vol 22 (1A) ◽  
pp. 93-106 ◽  
Author(s):  
J. PIVKO ◽  
J. MOTLIK ◽  
V. KOPEČNÝ ◽  
J.-E. FLÉCHON
2021 ◽  
pp. 1-7
Author(s):  
Dongjie Zhou ◽  
Zheng-Wen Nie ◽  
Xiang-Shun Cui

The cytoskeleton plays an orchestrating role in polarized cell growth. Microtubules (MTs) not only play critical roles in chromosome alignment and segregation but also control cell shape, division, and motility. A member of the plus-end tracking proteins, end-binding protein 1 (EB1), regulates MT dynamics and plays vital roles in maintaining spindle symmetry and chromosome alignment during mitosis. However, the role of EB1 in mouse oocyte meiosis remains unknown. Here, we examined the localization patterns and expression levels of EB1 at different stages. EB1 protein level was found to be stable during meiosis. EB1 mainly localized along the spindle and had a similar localization pattern as that of α-tubulin. The EB1 protein was degraded with a Trim-Away method, and the results were further confirmed with western blotting and immunofluorescence. At 12 h of culture after EB1 knockdown (KD), a reduced number of mature MII oocytes were observed. EB1 KD led to spindle disorganization, chromosome misalignment, and missegregation; β-catenin protein binds to actin via the adherens junctional complex, which was significantly reduced in the EB1 KD oocytes. Collectively, we propose that the impairment of EB1 function manipulates spindle formation, thereby promoting chromosomal loss, which is expected to fuel aneuploidy and possibly fertilization failure.


Author(s):  
Maria Cristina Budani ◽  
Gian Mario Tiboni

Nitric oxide (NO) is formed during the oxidation of L-arginine to L-citrulline by the action of multiple isoenzymes of NO synthase (NOS): neuronal NOS (nNOS), endotelial NOS (eNOS), and inducible NOS (iNOS). NO plays a relevant role in the vascular endothelium, in central and peripheral neurons, and in immunity and inflammatory systems. In addition, several authors showed a consistent contribution of NO to different aspects of the reproductive physiology. The aim of the present review is to analyse the published data on the role of NO within the ovary. It has been demonstrated that the multiple isoenzymes of NOS are expressed and localized in the ovary of different species. More to the point, a consistent role was ascribed to NO in the processes of steroidogenesis, folliculogenesis, and oocyte meiotic maturation in in vitro and in vivo studies using animal models. Unfortunately, there are few nitric oxide data for humans; there are preliminary data on the implication of nitric oxide for oocyte/embryo quality and in-vitro fertilization/embryo transfer (IVF/ET) parameters. NO plays a remarkable role in the ovary, but more investigation is needed, in particular in the context of human ovarian physiology.


Chemosphere ◽  
2020 ◽  
Vol 249 ◽  
pp. 126182 ◽  
Author(s):  
Zhi-Ming Ding ◽  
Li-Ping Hua ◽  
Muhammad Jamil Ahmad ◽  
Muhammad Safdar ◽  
Fan Chen ◽  
...  

Reproduction ◽  
2016 ◽  
Vol 152 (5) ◽  
pp. R143-R157 ◽  
Author(s):  
R B Gilchrist ◽  
A M Luciano ◽  
D Richani ◽  
H T Zeng ◽  
X Wang ◽  
...  

The cyclic nucleotides, cAMP and cGMP, are the key molecules controlling mammalian oocyte meiosis. Their roles in oocyte biology have been at the forefront of oocyte research for decades, and many of the long-standing controversies in relation to the regulation of oocyte meiotic maturation are now resolved. It is now clear that the follicle prevents meiotic resumption through the actions of natriuretic peptides and cGMP – inhibiting the hydrolysis of intra-oocyte cAMP – and that the pre-ovulatory gonadotrophin surge reverses these processes. The gonadotrophin surge also leads to a transient spike in cAMP in the somatic compartment of the follicle. Research over the past two decades has conclusively demonstrated that this surge in cAMP is important for the subsequent developmental capacity of the oocyte. This is important, as oocyte in vitro maturation (IVM) systems practised clinically do not recapitulate this cAMP surge in vitro, possibly accounting for the lower efficiency of IVM compared with clinical IVF. This review particularly focuses on this latter aspect – the role of cAMP/cGMP in the regulation of oocyte quality. We conclude that clinical practice of IVM should reflect this new understanding of the role of cyclic nucleotides, thereby creating a new generation of ART and fertility treatment options.


2012 ◽  
Vol 24 (1) ◽  
pp. 212
Author(s):  
A. M. Taiyeb Ridha ◽  
D. C. Kraemer

In vitro synchronization of oocyte nuclear and cytoplasmic maturation has been found to improve the IVF rate of ovarian oocytes in several species, including humans, in comparison with nonsynchronized in vitro-matured oocytes. Here, we tested the hypothesis that synchronization of oocyte meiotic maturation by an in vivo system in superovulated mice would increase the oocyte fertilization rate when compared to that of conventional superovulated oocytes. Recently, we observed that cilostazol (CZL), a PDE3-I, was able to inhibit mouse oocyte meiotic maturation in both in vitro and in vivo systems. Administering CZL at 7.5 mg, 4 or 7 h pre-hCG allowed retrieval of ovulated oocytes of which >95% were at MI stage, scored by Nikon stereo microscope (SMZ 1500). A conventional superovulation program was adapted in all treated and their control groups, in which mice were injected with eCG and after 48 h with hCG (7.5 IU for each hormone). On the second morning, 13 to 14 h post-hCG, mice were killed and oocytes were collected from oviducts and in vitro fertilized (control). For the treated groups, CZL was administered in a single 7.5 mg oral dose (gavage) 4 or 7 h before the hCG injection. On the second morning, CZL-treated animals were killed at the same timing as control animals and oocytes were retrieved from the oviduct and in vitro matured for 6 h (for those gavaged with CZL, 4 h pre-hCG) or 3 h (for those gavaged with CZL, 7 h pre-hCG) to MII oocytes before IVF. These groups were designated as in vivo-in vitro synchronized/matured oocytes. In other groups treated with CZL, 4 or 7 h pre-hCG, the ovulated oocytes were allowed to mature in the oviduct (full in vivo synchronization and maturation) and oocytes were retrieved and fertilized with the same fertilization timings as the in vivo-in vitro synchronized/matured oocytes. Oocytes were cultured for 1 day after IVF and examined for cleavage. Statistical differences were analyzed by cross-tabulated chi-square test. The full in vivo synchronization and maturation (for both CZL dose timings of 4 and 7 h pre-hCG) gave significantly higher early embryonic development rates compared with those of the control [89% (n = 219) and 92.2% (n = 374) vs 81.8% (n = 198); P = 0.034 and P < 0.0001, respectively]. The in vivo-in vitro synchronized/matured oocytes (CZL dose timing at 7 h, but not 4 h pre-hCG) gave significantly higher early embryonic development rates compared with those of the control [88.5% (n = 339) vs 83.4% (n = 458), respectively; P = 0.043]. However, the increase of the IVF rate of the oocytes from mice treated with CZL, 4 h pre-hCG, in the in vivo-in vitro synchronized/matured group was not significantly different from the control group [88.5% (n = 399) vs 83.4% (n = 458), respectively; P = 0.43]. It is concluded from the present study that synchronization of oocyte meiotic maturation by the in vivo and in vivo-in-vitro protocols can increase the IVF rate of oocytes in superovulated mice.


1978 ◽  
Vol 30 (1) ◽  
pp. 251-264
Author(s):  
R.M. Schultz ◽  
G.E. Letourneau ◽  
P.M. Wassarman

Nucleate and anucleate fragments of mouse oocytes have been isolated following treatment of fully grown oocytes with cytochalasin B. The nucleate oocyte fragments resume meiosis in vitro, progressing from dictyate of the first meiotic prophase to metaphase II (‘meiotic maturation’), and exhibit all of the changes in protein synthesis normally associated with meiotic maturation of mouse oocytes. The anucleate oocyte fragments also undergo certain of the changes in protein synthesis associated with meiotic maturation, despite the absence of nuclear progression. These results suggest that the acquisition of meiotic competence (i.e. the ability to undergo meiotic maturation) during growth of the mammalian oocyte is due to changes in the quality, rather than the quantity, of cytoplasm and that the reprogramming of protein synthesis during meiotic maturation is directed by RNA templates already present in the cytoplasm. The behaviour of anucleate oocyte fragments is discussed in terms of the proposed role for nucleoplasm in the initiation of changes in protein synthesis during meiotic maturation of mouse oocytes.


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