scholarly journals Cortical Granule Distribution and Expression Pattern of Genes Regulating Cellular Component Size, Morphogenesis, and Potential to Differentiation are Related to Oocyte Developmental Competence and Maturational Capacity In Vivo and In Vitro

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 815
Author(s):  
Magdalena Kulus ◽  
Wiesława Kranc ◽  
Michal Jeseta ◽  
Patrycja Sujka-Kordowska ◽  
Aneta Konwerska ◽  
...  

Polyspermia is an adverse phenomenon during mammalian fertilization when more than one sperm fuses with a single oocyte. The egg cell is prepared to prevent polyspermia by, among other ways, producing cortical granules (CGs), which are specialized intracellular structures containing enzymes that aim to harden the zona pellucida and block the fusion of subsequent sperm. This work focused on exploring the expression profile of genes that may be associated with cortical reactions, and evaluated the distribution of CGs in immature oocytes and the peripheral density of CGs in mature oocytes. Oocytes were isolated and then processed for in vitro maturation (IVM). Transcriptomic analysis of genes belonging to five ontological groups has been conducted. Six genes showed increased expression after IVM (ARHGEF2, MAP1B, CXCL12, FN1, DAB2, and SOX9), while the majority of genes decreased expression after IVM. Using CG distribution analysis in immature oocytes, movement towards the cortical zone of the oocyte during meiotic competence acquisition was observed. CGs peripheral density decreased with the rise in meiotic competence during the IVM process. The current results reveal important new insights into the in vitro maturation of oocytes. Our results may serve as a basis for further studies to investigate the cortical reaction of oocytes.

2015 ◽  
Vol 27 (7) ◽  
pp. 1082 ◽  
Author(s):  
Maricy Apparicio ◽  
Giuliano Q. Mostachio ◽  
Tathiana F. Motheo ◽  
Aracelle E. Alves ◽  
Luciana Padilha ◽  
...  

The aim of this study was to evaluate the influence of different bi-phasic systems with gonadotrophins and steroids on in vitro maturation rates of oocytes obtained from bitches at different reproductive stages (follicular, luteal, anoestrous). In System A (control) oocytes were matured for 72 h in base medium (BM) with 10 IU mL–1 human chorionic gonadotrophin (hCG), 1 μg mL–1 progesterone (P4) and 1 μg mL–1 oestradiol (E2); in bi-phasic System B oocytes were matured for 48 h in BM with hCG and for 24 h in BM with P4; in bi-phasic System C oocytes were matured for 48 h in BM with hCG, P4 and E2, and for 24 h in BM with P4; in System D, oocytes were cultured in BM without hormonal supplementation. Data were analysed by ANOVA. There was a positive effect of the bi-phasic systems on germinal vesicle breakdown, metaphase I and metaphase II rates, irrespective of reproductive status (P < 0.05). Bi-phasic systems were also beneficial for cortical granule distribution (an indication of cytoplasmic maturation) and its relationship to nuclear status: 74.5% of the oocytes cultured in System B and 85.4% of those cultured in System C presented both nuclear and cytoplasmic maturation (P < 0.001). The stage of the oestrous cycle did not influence maturation rates.


Reproduction ◽  
2017 ◽  
Vol 153 (6) ◽  
pp. 775-784 ◽  
Author(s):  
A Bertero ◽  
F Ritrovato ◽  
F Evangelista ◽  
V Stabile ◽  
R Fortina ◽  
...  

The purpose of this study was to observe in vitro-matured equine oocytes with an objective computerized technique that involves the use of a polarized light microscope (PLM) in addition to the subjective morphological evaluation obtained using a classic light microscope (LM). Equine cumulus-oocyte complexes (COCs, n = 922) were subjected to different in vitro maturation times (24, 36 or 45 h), however, only 36-h matured oocytes were analyzed using CLM. The 36-h matured oocytes that reached maturity were parthenogenetically activated to evaluate the quality and meiotic competence. Average maturation percentages per session in groups 1, 2 and 3 (24-, 36- and 45-h matured oocytes respectively) were 29.31 ± 13.85, 47.01 ± 9.90 and 36.62 ± 5.28%, whereas the average percentages of immature oocytes per session were 28.78 ± 20.17, 7.83 ± 5.51 and 22.36 ± 8.39% respectively. The zona pellucida (ZP) birefringent properties were estimated and correlated with activation outcome. ZP thickness and retardance of the inner layer of the zona pellucida (IL-ZP) were significantly increased in immature oocytes compared with mature oocytes (P < 0.001 and P < 0.01 respectively). The comparison between parthenogenetically activated and non-activated oocytes showed a significant increase in the area and thickness of the IL-ZP in parthenogenetically activated oocytes (P < 0.01). These results show that the 36-h in vitro maturation (IVM) protocol allowed equine oocytes to reach maturity, and PLM observation of ZP can be used to distinguish mature and immature oocytes as well as activated and non-activated oocytes.


2016 ◽  
Vol 28 (2) ◽  
pp. 235
Author(s):  
P. Dini ◽  
O. Bogado ◽  
K. Smits ◽  
A. VanSoom ◽  
P. Daels

It has been reported that immature, equine oocytes can be maintained in meiotic arrest at 24°C. To evaluate a commercial equine embryo holding medium for storage of equine oocyte at 24°C and to determine the effect of holding on maturation kinetics, cumulus‐oocyte complexes (COC) were recovered from slaughtered mares and placed in Syngro® Embryo Holding Solution at 22–25°C for 18–20 h (OH Group) or placed directly in DMEM-F12-based in vitro maturation (IVM) conditions (D-Mat Group) at 5% CO2 in air at 38.5°C. Maturation rate (metaphase II percentage; MII%) was assessed (presence of polar body under stereomicroscope) after denudation at 22, 24, and 28 h. After assessment, the denuded oocytes that were considered immature were placed back in IVM, reassessed at 24 and 28 h, and MII% was compared with that of oocytes remaining uninterrupted in IVM for 24 and 28 h. One-way ANOVA was used to compare dependent variable in different groups using PROC ANOVA (SAS, version 9.2, SAS Institute, Cary, NC, USA). A random selection of mature oocytes from both groups were fertilised using intracytoplasmic sperm injection (ICSI). A total of 250 injected oocytes were cultured in DMEM-F12 with 10% FCS. Blastocyst rates in OH and D-mat groups were similar (7.1% v. 6.3%). At 22 h, significantly more oocytes reached the MII stage in the OH group than in the D-Mat group, but MII% was similar in both groups at 24 and 28 h (Table 1). Denuded, immature oocytes reached similar maturation rate as the undenuded oocytes in the same group. Our data suggest that oocytes can be held in Syngro® Embryo Holding Solution at 22–25°C for 18–20 h without compromising oocyte developmental competence. Overnight holding of oocytes accelerates maturation with similar maturation rate at 22, 24, and 28 h of IVM in the OH group. Denudation of immature oocytes after 22 h of IVM and returning the denuded oocytes to IVM does not affect the progression of maturation. In subsequent experiment, overnight held oocytes were fixed and stained (Hoechst 33342) and MII% was evaluated after 20, 22, and 28 h of IVM. Chromatin configuration confirmed that stored oocytes reach the MII stage at 22 h. Maturation rates were significantly lower at 20 h, suggesting that 22 h of IVM is required for stored oocytes. Table 1.Maturation rates (% in MII stage) at 22, 24, and 28 h of IVM for equine oocytes held in Syngro® Embryo Holding Medium before IVM (OH) and oocytes placed directly in IVM (D-Mat) Thanks to I. Lemahieu and P. Van Damme. Study was supported by the Special Research Fund at UGent.


Zygote ◽  
2004 ◽  
Vol 12 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Boon Chin Alexis Heng ◽  
Ng Soon Chye

This study attempted to develop a ‘less meiotically competent’ murine model for oocyte in vitro maturation (IVM), which could more readily be extrapolated to human clinical assisted reproduction. Oocyte meiotic competence was drastically reduced upon shortening the standard duration of in vivo gonadotrophin stimulation from 48 h to 24 h, and by selecting only naked or partially naked germinal vesicle oocytes, instead of fully cumulus enclosed oocyte complexes. With such a less meiotically competent model, only porcine granulosa coculture significantly enhanced the oocyte maturation rate in vitro, whereas no significant enhancement was observed with macaque and murine granulosa coculture. Increased serum concentrations and the supplementation of gonadotrophins, follicular fluid and extracellular matrix gel within the culture medium did not enhance IVM under either cell-free or coculture conditions. Culture medium conditioned by porcine granulosa also enhanced the maturation rate, and this beneficial effect was not diminished upon freeze–thawing. Enhanced IVM in the presence of porcine granulosa coculture did not, however, translate into improved developmental competence, as assessed by in vitro fertilization and embryo culture to the blastocyst stage.


2005 ◽  
Vol 17 (2) ◽  
pp. 216
Author(s):  
Y.H. Choi ◽  
L.B. Love ◽  
D.D. Varner ◽  
K. Hinrichs

At the time of recovery, immature equine oocytes may be separated into those with either expanded cumuli (Ex) or compact cumuli (Cp). The Cp oocytes originate from viable follicles but are largely juvenile, with low meiotic competence (20 to 30% maturation to MII), and possibly reduced developmental competence. We previously found that in Cp oocytes recovered immediately after slaughter, suppression of meiosis with roscovitine for 24 h before maturation increased embryo development at 4 days after intracytoplasmic sperm injection (ICSI; Franz et al. 2003 Reproduction 125, 693–700). The present study was conducted to evaluate the effect of roscovitine suppression on nuclear maturation and blastocyst formation of Cp oocytes recovered after transport of ovaries from the abattoir (i.e. recovered 5–9 h after slaughter). Compact oocytes recovered from transported ovaries were cultured in M199 with 10% FBS containing 66 μM roscovitine with or without an oil cover. After 16–18 or 24 h, oocytes were fixed to examine the chromatin configuration. Treatment for 16–18 h without oil resulted in the lowest rate of meiotic resumption (0%); thus this treatment was utilized in further studies. Resumption in other treatments ranged from 3 to 6%. Following roscovitine suppression, oocytes were cultured for 30 h in M199 with 10% FBS and 5 μU mL−1 FSH for maturation; control oocytes were cultured for 30 h in the same medium immediately after recovery. Mature oocytes were subjected to ICSI, then cultured in DMEM/F-12 with 10% FBS with or without co-culture with equine oviductal epithelial cells under mineral oil in 5% CO2 in air at 38.2°C, and then evaluated at 7.5 days. Progression to MII (82/376, 22%) after maturation of roscovitine-treated oocytes was similar to that for control oocytes (74/395, 19%). There was no significant difference in cleavage rates after ICSI (72–78%) among treatments. Development to blastocyst was highest in roscovitine-treated oocytes in DMEM/F-12 with co-culture (11/30, 37%); this was significantly higher than that of non-treated oocytes in DMEM/F-12 alone (5/36, 14%), but similar to that of non-treated/DMEM/F-12/co-culture (10/37, 27%) and roscovitine/DMEM/F-12 alone (8/39, 21%). These data indicate that roscovitine induces a fully reversible meiotic suppression in Cp equine oocytes recovered 5–9 h after slaughter, and that this suppression does not harm subsequent developmental competence. This treatment may be used to manipulate the time of onset of maturation of equine oocytes for ease of subsequent procedures. Co-culture with oviductal epithelial cells tended to increase blastocyst rate (P = 0.1, Fisher's exact test) in contrast to our previous findings with embryos from Ex oocytes (Choi et al. 2004 Biol. Reprod. 70, 1231–1238). Further work is needed to determine whether this is related to differences in intrinsic developmental competence between oocyte types. This work was supported by the Link Equine Research Endowment Fund (Texas A&M University).


Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1034
Author(s):  
Joohyeong Lee ◽  
Eunhye Kim ◽  
Seon-Ung Hwang ◽  
Lian Cai ◽  
Mirae Kim ◽  
...  

This study aimed to examine the effects of treatment with glucuronic acid (GA) and N-acetyl-D-glucosamine (AG), which are components of hyaluronic acid (HA), during porcine oocyte in vitro maturation (IVM). We measured the diameter of the oocyte, the thickness of the perivitelline space (PVS), the reactive oxygen species (ROS) level, and the expression of cumulus cell expansion and ROS-related genes and examined the cortical granule (CG) reaction of oocytes. The addition of 0.05 mM GA and 0.05 mM AG during the first 22 h of oocyte IVM significantly increased oocyte diameter and PVS size compared with the control (non-treatment). The addition of GA and AG reduced the intra-oocyte ROS content and improved the CG of the oocyte. GA and AG treatment increased the expression of CD44 and CX43 in cumulus cells and PRDX1 and TXN2 in oocytes. In both the chemically defined and the complex medium (Medium-199 + porcine follicular fluid), oocytes derived from the GA and AG treatments presented significantly higher blastocyst rates than the control after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT). In conclusion, the addition of GA and AG during IVM in pig oocytes has beneficial effects on oocyte IVM and early embryonic development after PA and SCNT.


2016 ◽  
Vol 95 (4) ◽  
pp. 76-76 ◽  
Author(s):  
A. Okamoto ◽  
M. Ikeda ◽  
A. Kaneko ◽  
C. Kishida ◽  
M. Shimada ◽  
...  

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