Reduced oxygen concentration improves the developmental competence of mouse oocytes following in vitro maturation

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.

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

Annals of Animal Science ◽

10.1515/aoas-2017-0029 ◽

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.

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Effect ofPapaver rhoeasextract on in vitro maturation and developmental competence of immature mouse oocytes

Reproductive Medicine and Biology ◽

10.1007/s12522-010-0059-0 ◽

2010 ◽

Vol 9 (4) ◽

pp. 211-215 ◽

Cited By ~ 7

Author(s):

Afsaneh Golkar-Narenji ◽

Hussein Eimani ◽

Firooz Samadi ◽

Saeed Hasani ◽

Abdol-Hossein Shahverdi ◽

...

Keyword(s):

In Vitro Maturation ◽

Developmental Competence ◽

Mouse Oocytes ◽

Immature Mouse

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

Reproduction Fertility and Development ◽

10.1071/rdv20n1ab243 ◽

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.

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