243 NUCLEOSIDES REDUCE THE POTENTIAL OF THE MITOCHONDRIAL INNER MEMBRANE AND THE DEVELOPMENTAL COMPETENCE OF MOUSE OOCYTES DURING IN VITRO MATURATION

2008 ◽  
Vol 20 (1) ◽  
pp. 201
Author(s):  
W. Fujii ◽  
H. Funahashi
Keyword(s):  
In Vitro Maturation ◽  
Developmental Competence ◽  
Mouse Oocytes ◽  
Mitochondrial Inner Membrane ◽  
Maturation Medium ◽  
Equine Chorionic Gonadotropin ◽  
Post Hoc ◽  
Pronuclear Formation

Although nucleosides such as adenosine exist in follicular fluid and decrease during oocyte maturation (Eppig et al. 1985 Biol. Reprod. 33, 1041–1049), the role of nucleosides is still unclear. The present study was undertaken to determine the effect of nucleoside on nuclear and cytoplasmic maturation of mouse oocytes. Oocyte–cumulus complexes (OCCs)were collected from the large antral follicles of C57BL/6J female mice (3–5 weeks old) 4 h after a combination injection of equine chorionic gonadotropin (eCG) and hCG with a 48-h interval, and cultured in maturation medium (αMEM containing 3 mg mL–1 BSA, 0.23 mm Na pyruvate and antibiotics) with or without ribo- and deoxyribo-nucleosides (10–11 µg mL–1) for 12 h. Statistical analyses in this study were carried out by ANOVA and Bonferroni/Dunn's post hoc test. Regardless of the presence of nucleosides, a majority of oocytes developed to the metaphase-II stage in vitro, and the incidence was not different with in vivo-matured oocytes. However, the mitochondrial membrane potential (MMP) of oocytes was significantly lower when the oocytes were matured in the presence of nucleosides, as compared with nucleoside-free controls. In the scanning experiment of MMP level during in vitro maturation (IVM), the MMP of oocytes maturing in vivo increased between 8 and 12 h after hCG injection, whereas no rises of MMP was observed in oocytes matured in vitro in the presence of nucleosides. To examine the affecting period of nucleosides, OCCs were cultured for the first 4 h or the latter 8 h of IVM in the presence of nucleosides. MMP of the oocytes was significantly lower only when the OCCs were exposed to nucleosides for the latter 8 h of IVM. To determine if adenosine in the nucleosides (10 µg mL–1) affects the MMP of oocytes, OCCs were exposed to adenosine or a mixture of guanosine, cytidine, and uridine during the latter 8 h of IVM. The MMP of oocytes exposed to adenosine was lower than that of in vivo-matured oocytes and of oocytes exposed to a mixture of guanosine, cytidine, and uridine. To determine the effect of nucleosides on the developmental competence, oocytes exposed to adenosine during the latter 8 h of IVM were cultured in kSOMaa containing 1 mg mL–1 BSA after activation in the presence of 10 mm SrCl2 and 5 µg mL–1 cytochalasin B for 6 h. Pronuclear formation and early development of those were compared with artificially activated oocytes matured in vivo or in the absence of nucleosides. The incidences of pronuclear formation and cleavage of oocytes matured in the presence of adenosine following activation were extremely decreased, as compared with control oocytes matured in vivo or in the absence of adenosine. These observations indicate that nucleosides, at least adenosine, inhibit an increase of MMP of oocytes during the latter half of meiotic maturation, and detrimentally affect the developmental competence of murine oocytes.

scholarly journals ANALYSIS OF INDICATORS OF FERTILITY OF PORCINE OOCYTES THAT HAVE FINISHED GROWTH PHASE IN VIVO ASPIRATED FROM THE FOLLICLES OF DIFFERENT DIAMETERS

2018 ◽  
Vol 51 ◽  
pp. 240-247
Author(s):  
T. I. Kuzmina ◽  
S. I. Kovtun ◽  
E. C. Usenbekov ◽  
O. A. Epishko ◽  
V. N. Stefanova
Keyword(s):  
Oocyte Maturation ◽  
Growth Phase ◽  
In Vitro Maturation ◽  
Developmental Competence ◽  
Brilliant Cresyl Blue ◽  
Cresyl Blue ◽  
Maturation Medium ◽  
Selection Of

The selection of competent oocytes to completion of meiosis in vitro, fertilization or reconstructing (cloning, transgenesis) is the initial stage of cell reproductive technologies in animal husbandry. The development of effective methods of early prediction prospective potencies for extracorporeal maturation and fertilization of oocyte is the actual problem of rapidly developing embryo technologies. Numerous factors determined developmental competence of the oocytes. Brilliant cresyl blue (BCB) staining has been used for selection of oocytes from several mammalian species, including pigs (Ericsson S. et al, Theriogenology, 39(1): p.214, 1993). BCB determines the intracellular activity of glucose-6-phosphate dehydrogenase, which plays an important role in cell growth, as a key enzyme in the pentose phosphate cycle. The enzyme activity in the growing oocyte increases, opposite in the oocytes that have finished growth phase it decreases (Alm et al., 2005). BCB - diagnostics of the initial population of oocytes based on staining with vital dye brilliant cresyl blue have proposed as an effective indicator of completion of oocyte growth phase.   The aim of the present study was to evaluate the developmental competence of porcine oocytes that have finished growth phase (BCB+) in vivo depending on diameter (d) of follicles (d <3 mm, 3 –5 mm, <6 mm). Before in vitro maturation compact cumulus oocyte complexes were incubated in BCB solution (13 μM) for 90 minutes. Treated oocytes were divided into BCB­-­ (colourless cytoplasm) and BCB+ (coloured cytoplasm). We have found that different diameter follicles contain both growing oocytes and oocytes that have finished growth phase in vivo (follicles d <3 mm – 71%; follicles d 3 - 5 mm – 86%; follicles d 6 – 8mm – 86%). Only BCB+ oocytes were used in the experiments. The medium used for oocyte maturation was NCSU 23 supplemented with 10% follicular fluid, 0.1 mg/ml cysteine,10 IU/ml eCG and 10 IU/ml hCG. Follicular fluid was collected from follicles with 3 - 6 mm in diameter. Oocyte cumulus complexes were cultured in maturation medium with pieces of wall (600 – 900 µmin length) from non athretic healthy follicles (d 3 – 6mm). After 20 – 22 h of culture, oocyte cumulus complexes and pieces of wall were washed and transferred into the same maturation medium but without hormonal supplements for another 20-22 h of culture. After in vitro maturation, oocytes were fertilized in vitro and embryos were cultured by standard protocols (Kuzmina et al., 2008). We have estimated oocyte maturation, quality of early embryos including status of chromatin (Tarkowsky, 1966). All chemicals used in this study were purchased from Sigma-Aldrich. Data were analyzed by Chi2 – test. Oocytes that have finished their growth phase of examined species have shown high potency to maturation in all groups of experiment (follicles d <3 mm – 78%; follicles d 3 –5mm – 79%; follicles d 6 – 8 mm– 85%). Level of oocyte with degenerative chromatin had not significant differences in all groups of experiments. We did not find significant differences between the level of cleavage and blastocyst in all groups of experiments. Percentages of cleavage and blastocyst in the groups were: follicles d <3 mm– 43% (27/63) and 29% (18/63); follicles d 3 – 5 mm– 46% (45/98) and 35% (34/98); follicles d < 6 – 8 mm–48% (28/58) and 28% (16/58) (χ² test). Analysis of morphology and chromatin abnormalities in embryos has not shown significant differences between the groups of experiment. Developmental competence of Sus Scrofa Domesticus oocytes that have finished growth phase in vivo, isolated from the follicles of various diameters (<3 mm, 3 – 5mm and 6 – 8mm) was analyzed. There were no significant differences in the level of cleavage and embryos on the blastocyst stage and their morphological characteristics. The findings suggest the equal potency to the maturation and fertilization of oocytes that have finished growth phase in vivo, independently of diameter of follicles.

scholarly journals α-Tocopherol modifies the expression of genes related to oxidative stress and apoptosis during in vitro maturation and enhances the developmental competence of rabbit oocytes

2018 ◽  
Vol 30 (12) ◽  
pp. 1728 ◽  
Author(s):  
M. Arias-Álvarez ◽  
R. M. García-García ◽  
J. López-Tello ◽  
P. G. Rebollar ◽  
A. Gutiérrez-Adán ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
In Vitro Maturation ◽  
Cumulus Cell ◽  
Rabbit Model ◽  
Developmental Competence ◽  
Antioxidant Agents ◽  
Junction Protein

The developmental competence of in vitro maturation (IVM) oocytes can be enhanced by antioxidant agents. The present study investigated, for the first time in the rabbit model, the effect of adding α-tocopherol (0, 100, 200 and 400 µM) during IVM on putative transcripts involved in antioxidant defence (superoxide dismutase 2, mitochondrial (SOD2), glutathione peroxidase 1 (GPX1), catalase (CAT)), cell cycle regulation and apoptosis cascade (apoptosis tumour protein 53 (TP53), caspase 3, apoptosis-related cysteine protease (CASP3)), cell cycle progression (cellular cycle V-Akt murine thymoma viral oncogene homologue 1 (AKT1)), cumulus expansion (gap junction protein, alpha 1, 43 kDa (GJA1) and prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclo-oxygenase) (PTGS2)) and metabolism (glucose-6-phosphate dehydrogenase (G6PD)). Meiotic progression, mitochondrial reallocation, cumulus cell apoptosis and the developmental competence of oocytes after IVF were also assessed. Expression of SOD2, CAT, TP53, CASP3 and GJA1 was downregulated in cumulus–oocyte complexes (COCs) after IVM with 100 μM α-tocopherol compared with the group without the antioxidant. The apoptotic rate and the percentage of a non-migrated mitochondrial pattern were lower in COCs cultured with 100 μM α-tocopherol, consistent with better-quality oocytes. In fact, early embryo development was improved when 100 μM α-tocopherol was included in the IVM medium, but remained low compared with in vivo-matured oocytes. In conclusion, the addition of 100 μM α-tocopherol to the maturation medium is a suitable approach to manage oxidative stress and apoptosis, as well as for increasing the in vitro developmental competence of rabbit oocytes.

249 FOLLICLE-STIMULATING HORMONE AND DIBUTYRYL cAMP TREATMENTS DURING IN VITRO MATURATION IMPROVE THE DEVELOPMENTAL COMPETENCE OF MOUSE OOCYTES

2008 ◽  
Vol 20 (1) ◽  
pp. 204
Author(s):  
R. Oishi ◽  
Y. Isaji ◽  
H. Imai ◽  
M. Yamada
Keyword(s):  
In Vitro Maturation ◽  
Basal Medium ◽  
Cumulus Cells ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Control Medium ◽  
Dibutyryl Camp ◽  
Mouse Oocytes ◽  
Junctional Communication

The high level of cyclic adenosine monophosphate (cAMP), which is provided to the oocytes from cumulus cells via gap junctional complexes in cumulus-enclosed oocytes (CEOs), is known to contribute to meiotic arrest at the germinal vesicle (GV) stage of CEOs. However, whether intraoocyte cAMP during the period of in vitro maturation (IVM) affects postfertilization developmental competence of mouse oocytes still remains unclear. The aim of this study was to examine the effects of FSH or dibutyryl cAMP (dbcAMP) treatment during IVM on in vitro development of mouse oocytes after in vitro fertilization (IVF). Whether a junctional association between cumulus cells and the oocyte would be essential for a cytoplasmic maturation-promoting effect was also examined. CEOs were isolated from and eCG-primed 3-week-old ICR mouse by rupturing preovulatory follicles with needles in M16 medium with 5% FCS and essential and nonessential amino acids (basal medium). IVM media used were basal medium without (control) or with 100 µm dbcAMP or 1 IU mL–1 FSH. Carbenoxolone (100 µm, CBX), an inhibitor of gap junction, was used to inhibit a junctional association between cumulus cells and the oocyte. Denuded oocytes (DOs) were prepared by repeatedly pipetting in basal medium with 0.2% hyaluronidase. CEOs and DOs were cultured in IVM media at 37�C under 5% CO2 in air for 16.5 h, and then transferred to TYH medium (a modified Krebs-Ringer bicarbonate medium) containing 0.4% BSA, followed by insemination with capacitated sperm. After 6 h of IVF, inseminated oocytes were cultured in KSOM medium with 0.3% BSA. Development to the 2-cell and blastocyst stages was estimated at 24 h and 120 h after IVF, respectively. All experiments were done in 3 replicates, and the statistical analysis was carried out by ANOVA and Fisher's protected least-squares difference (PLSD) test. When CEOs were matured in IVM media, the rates of postfertilization development to the 2-cell and blastocyst stages of oocytes matured in the control medium were very low(29% and 13%, respectively), whereas those of oocytes matured with FSH or dbcAMP significantly increased (FSH: 61% and 52%, dbcAMP: 63 and 57%, respectively, v. control; P < 0.05). Next, when CEOs were matured in basal medium with 1 IU mL–1 FSH and 100 µm CBX, the developmental rate to the 2-cell stage (56%) was similar to that in medium with FSH alone (61%) but the rate to the blastocyst stage (40%) was little lower compared with that in medium with FSH alone (52%), although not significantly different (P > 0.05). Furthermore, when DOs were matured in IVM media, the developmental rates to the blastocyst stage after IVF of the oocytes matured with FSH or dbcAMP significantly increased (FSH: 25%, dbcAMP: 15%; P < 0.05) compared with those in control medium (7%). Taken together, it is suggested that increasing the concentration of intraoocyte cAMP during the IVM period is important to improve the developmental competence after IVF of mouse oocytes, and that the competence is acquired in part in a cumulus-oocyte junctional communication-independent manner.

3 IN VITRO MATURATION ALTERS GENE EXPRESSION IN MOUSE OOCYTES

2008 ◽  
Vol 20 (1) ◽  
pp. 82
Author(s):  
M. Paczkowski ◽  
C. Bidwell ◽  
D. Spurlock ◽  
J. Waddell ◽  
R. L. Krisher
Keyword(s):  
Gene Expression ◽  
Cell Death ◽  
Dna Methyltransferase ◽  
In Vitro Maturation ◽  
Fold Increase ◽  
Developmental Competence ◽  
Differentially Expressed ◽  
Dna Methyltransferase 1

The in vitro culture environment significantly impacts nuclear maturation, fertilization, embryonic development, and epigenetic competence; however, our knowledge of the effects of in vitro maturation on oocyte developmental competence, and specifically cytoplasmic maturation, is limited. The objective of this experiment was to identify alterations in the transcriptome of oocytes matured in vitro compared to those matured in vivo that correlate to developmental competence. Immature oocytes were collected from Day 26 and 7-8-week-old B6D2F1 mice 48 h post-pregnant mare serum gonadotropin (PMSG) administration and matured for 16 h in Gmat supplemented with 0.5 mm citric acid, 0.5 mm cysteamine, 100 ng mL–1 epidermal growth factor (EGF), 0.05% insulin-transferrin-selenium (ITS; v/v), 0.01% recombumin (v/v) and 2 mg mL–1 fetuin. In vivo-matured oocytes from females of the same ages were collected from the oviducts 62 h post-PMSG and 14 h post-hCG and mating to vasectomized males. In vivo- and in vitro-matured oocytes were identified visually by the presence of the first polar body. Mature oocytes were pooled into three groups of 150 oocytes per treatment and lysed; poly A+ RNA was extracted. Samples were processed through two cycles of linear amplification and hybridized to the GeneChip� Mouse Genome 430 2.0 Array (Affymetrix, Inc., Santa Clara, CA, USA), with three arrays per treatment. Microarray data were sorted and filtered to include genes that were classified as having two present calls per treatment. The data were then normalized to the chip median and analyzed using a one-way analysis of variance; the level of significance was calculated at P < 0.01. In total, 2.17% (482/22170) and 1.61% (358/22170) of genes were differentially expressed between in vitro- and in vivo-matured oocytes in Day 26 and 7–8-week-old mice, respectively. However, 72.82% (351/482) and 67.87% (243/358) of differentially expressed genes had increased abundance in the in vitro- and in vivo-matured oocytes, respectively. Transcripts involved in gene expression, cellular growth and proliferation, and cellular development were increased in in vivo-matured oocytes from both age groups compared to those matured in vitro. Cell death was one of the higher ranking functional groups increased in the 7–8-week-old in vitro-matured oocytes compared to the 7–8-week-old in vivo-matured oocytes. Specific genes altered by in vitro maturation conditions in Day 26 oocytes were DNA methyltransferase 1 (>7-fold increase in vivo), caspase 8 (>4-fold increase in vivo), and eukaryotic translation initiation factor 1B (>4-fold increase in vivo). DNA methyltransferase 1 and ubiquitin-conjugating enzyme E2T were significantly increased in in vivo-matured 7–8-week-old oocytes (>3-fold and >5-fold, respectively). These results indicate that gene expression is altered in oocytes matured in vitro compared to those matured in vivo. Based on the functional annotations of genes differentially expressed, dysregulation of gene expression in the oocyte resulting in altered DNA methylation and an up-regulation in cell death pathways are potential developmental mechanisms influenced by in vitro culture conditions that correlate to reduced embryonic developmental potential.

Paradoxical effects of kisspeptin: it enhances oocyte in vitro maturation but has an adverse impact on hatched blastocysts during in vitro culture

2012 ◽  
Vol 24 (5) ◽  
pp. 656 ◽  
Author(s):  
Islam M. Saadeldin ◽  
Ok Jae Koo ◽  
Jung Taek Kang ◽  
Dae Kee Kwon ◽  
Sol Ji Park ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Formation Rate ◽  
Early Period ◽  
Threshold Effect ◽  
Developmental Competence ◽  
Control Group ◽  
Maturation Medium ◽  
Paradoxical Effects

Kisspeptin (Kp) is best known as a multifunctional peptide with roles in reproduction, the cardiovascular system and cancer. In the present study the expression of kisspeptin hierarchy elements (KISS1, GNRH1 and LHB) and their receptors (KISS1R, GNRHR and LHCGR, respectively) in porcine ovary and in cumulus–oocyte complexes (COCs) were investigated, as were its effects on the in vitro maturation (IVM) of oocytes and their subsequent ability to sustain preimplantation embryo competence after parthenogenetic electrical activation. Kp system elements were expressed and affected IVM of oocytes when maturation medium was supplemented with 10–6 M Kp. Oocyte maturation, maternal gene expression (MOS, GDF9 and BMP15), blastocyst formation rate, blastocyst hatching and blastocyst total cell count were all significantly increased when oocytes were matured in medium containing Kp compared with the control group (without Kp). A Kp antagonist (p234) at 4 × 10–6 M interfered with this hierarchy but did not influence the threshold effect of gonadotrophins on oocyte maturation. FSH was critical and permissive to Kp action on COCs by increasing the relative expression of KISS1R. In contrast, Kp significantly increased apoptosis, the expression of pro-apoptotic gene, BAK1, and suppressed trophoblast outgrowths from hatched blastocysts cultured on feeder cells. The present study provides the first functional evidence of the Kp hierarchy in porcine COCs and its role in enhancing oocyte maturation and subsequent developmental competence in an autocrine–paracrine manner. However, Kp supplementation may have a harmful impact on cultured hatched blastocysts reflecting systemic or local regulation during the critical early period of embryonic development.

scholarly journals Quercetin improves developmental competence of mouse oocytes by reducing oxidative stress during in vitro maturation

2018 ◽  
Vol 18 (1) ◽  
pp. 87-98
Author(s):  
Seyede Zahra Banihosseini ◽  
Marefat Ghaffari Novin ◽  
Hamid Nazarian ◽  
Abbas Piryaei ◽  
Siavash Parvardeh ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Embryo Development ◽  
In Vitro Maturation ◽  
Mature Oocyte ◽  
Developmental Competence ◽  
Nuclear Maturation ◽  
Mouse Oocytes ◽  
Blastocyst Rate ◽  
And Control

Abstract Quercetin is a natural flavonoid with strong antioxidant activity. In the present study, we evaluate the influence of different concentrations of quercetin (QT) on intracytoplasmic oxidative stress and glutathione (GSH) concentration, during in vitro maturation (IVM) and fertilization in mouse oocytes. IVM was carried out in the presence of control (QT0), 5 (QT5), 10 (QT10), and 20 (QT20) μg/mL of QT. Nuclear maturation, intracellular GSH and ROS content were evaluated following the IVM. In these oocytes, we subsequently evaluated the effect of QT supplementation on embryo development, including 2-cell, 8-cell, and blastocyst rate. The results of the present study showed that the supplementation of 10 μg/mL QT in maturation medium increased the number of MII oocytes. In addition, fertilization and blastocyst rate in QT10 treatment group were significantly higher in comparison to the other groups, and elevated the amount of intracellular GSH content compared to other QT concentrations and control groups. The intracellular ROS level was the lowest among oocytes matured in Q5 and Q10 treatment groups. This result suggested that quercetin dose-dependently improves nuclear maturation and embryo development, via reducing intracytoplasmic oxidative stress in mature oocyte.

314 MELATONIN ON IN VIVO AND IN VITRO MATURATION OF MOUSE OOCYTES

2015 ◽  
Vol 27 (1) ◽  
pp. 246 ◽  
Author(s):  
H. Fernandes ◽  
L. Schefer ◽  
F. C. Castro ◽  
C. L. V. Leal
Keyword(s):  
Ovarian Stimulation ◽  
In Vitro Maturation ◽  
F1 Hybrids ◽  
Saline Control ◽  
Control Group ◽  
Mouse Oocytes ◽  
Maturation Rate ◽  
Different Doses

Melatonin is a pineal hormone related to the control of the circadian cycle, besides the reproductive seasonality of some animal species, and has shown positive effects on oocyte maturation and embryo development. The aim of this study was to assess the effects of melatonin on in vivo and in vitro maturation of mouse oocytes. Female F1 hybrids (C57BL/6 × CBA; n = 8 per group/treatment) were used in 3 different treatments (trt) groups: (I) in vivo trt: mice received 2 different doses of melatonin injections, 10 and 20 mg kg–1 per IP including a saline control dose (0 mg kg–1 per IP) for 4 days along with ovarian stimulation trt of 5 IU of eCG IP, followed by 5 IU of hCG IP 48 h later, and cumulus-oocyte complexes (COC) were collected 16 h after hCG; (II) mice received a similar in vivo melatonin trt, but ovarian stimulation trt was only 5 IU of eCG, no hCG, and COC were collected after 48 h and subsequently matured in vitro with 0.5 µg mL–1 of FSH for 16 h; (III) in vitro maturation of oocytes: COC were collected 48 h after 5 IU of eCG and maturated in the presence of 3 different doses of melatonin (10–9, 10–6, and 10–3 M) or 0.5 µg mL–1 of FSH (control) for 16 h. In vitro-maturing oocytes were in incubated at 37°C, 5% CO2, and 95% humidity. Maturation rates were evaluated according to the presence of the first polar body under an inverted microscope. Statistical analyses were performed by ANOVA followed by Tukey's test (4 replicates). In the first treatment, 20 mg kg–1 of melatonin showed the highest in vivo maturation rate, 80.3% (61/76), while 10 mg kg–1 of melatonin was 62.4% (53/85) and the saline control group was 69.4% (77/111), but differences were not significant (P > 0.05). For in vitro maturation of oocytes from animals previously treated with melatonin, the 10 mg kg–1 of melatonin group had the highest maturation rate, 53.2% (99/186), in comparison with the saline and 20 mg kg–1 of melatonin groups, which showed 46.6 (88/189) and 39.0% (85/218), respectively; again, no differences were detected (P > 0.05). In the last treatment, the maturation rates increased from 48.9 (43/88) to 53.7 (51/95) and 56.0% (56/100) as the melatonin concentrations decreased from 10–3, 10–6, and 10–9 M, respectively. The control group had the highest rate of 57.3% (55/96), but no statistical differences were observed (P = 0.706). In conclusion, under the conditions studied, melatonin was unable to improve the maturation rate neither after in vivo nor in vitro treatment. However, during in vitro maturation, melatonin alone was as efficient as FSH in promoting maturation in murine oocytes, indicating its potential effect on stimulating meiosis. Therefore, the role of melatonin in stimulating meiosis needs further investigation.Acknowledgments to FAPESP for fellowship (HF) and funding (CLVL).

313 PRE-IN VITRO MATURATION WITH CYCLIC AMP AND CYCLIC GMP MODULATORS IMPROVES DEVELOPMENTAL COMPETENCE OF MOUSE OOCYTES

2015 ◽  
Vol 27 (1) ◽  
pp. 245 ◽  
Author(s):  
N. W. Santiquet ◽  
A. F. Greene ◽  
W. B. Schoolcraft ◽  
R. L. Krisher
Keyword(s):  
Embryo Development ◽  
In Vitro Maturation ◽  
Subsequent Development ◽  
Developmental Competence ◽  
Nuclear Maturation ◽  
Oocyte Developmental Competence ◽  
Oocyte Collection ◽  
Short Period

In vitro maturation (IVM) of cumulus-oocyte complexes (COC) results in oocytes with reduced quality and is still not as efficient as in vivo maturation in most species. One hypothesis that could explain the low developmental competence of oocytes following IVM is that the oocytes resume meiosis too quickly after being retrieved from the follicles. Studies in mice and bovine have shown that a short period of prematuration in the presence of cAMP modulators, before IVM, enhances oocyte developmental competence. Moreover, other studies have recently demonstrated that cGMP is also a crucial molecule involved in meiotic resumption. Here, our objective was to examine the effect of a cGMP modulator in combination with a cAMP modulator during a short period of prematuration on mouse oocyte nuclear maturation and subsequent embryo development following IVF. The COC were collected (6 replicates) from 2-month-old outbred CF1 mice 48 h after PMSG (5 IU) injection in the presence (pre-IVM) or absence (control) of cGMP and cAMP modulators. Pre-IVM COC (n = 184) were then placed in prematuration medium that also contained these cGMP and cAMP modulators. After 2 h, pre-IVM COC were washed and transferred to our in-house prepared, completely defined IVM medium (Paczkowski et al. 2014 Reprod.) for the remaining 16 h of culture; 10 oocytes per 50 µL drop under oil, at 37°C in 7.5% CO2 and 6.5% O2 due to the increased altitude at our location. Control COC (n = 161) were matured in the same IVM medium under identical conditions for 18 h, without prematuration. After IVM, oocytes were fixed for assessment of nuclear maturation, or fertilized and cultured in vitro and subsequent development (96 and 112 h) was recorded (Paczkowski et al. 2014 Reprod.). Results were analysed by ANOVA. A short 2-h prematuration period in the presence of cGMP and cAMP modulators had no impact on oocyte nuclear maturation to metaphase II after IVM or on embryo cleavage after IVF. However, pre-IVM treatment improved the developmental competence of the oocyte, as demonstrated by increased embryo development. More (P < 0.02) blastocysts (96 h of culture) and hatched blastocysts (112 h of culture) developed in the pre-IVM treatment compared to control (31.0 ± 3.4 v. 19.9 ± 3.2%; 31.5 ± 3.4 v. 19.9 ± 3.2%, respectively). In conclusion, a combination of cGMP and cAMP modulators during oocyte collection and a subsequent short pre-IVM improves oocyte developmental competence and could therefore be a potential tool to improve embryo yield following IVM.

Sign in / Sign up

Export Citation Format

Share Document