scholarly journals Oocyte Competence Biomarkers Associated With Oocyte Maturation: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Batara Sirait ◽  
Budi Wiweko ◽  
Ahmad Aulia Jusuf ◽  
Dein Iftitah ◽  
R. Muharam
Keyword(s):  
Oocyte Maturation ◽  
Blastocyst Stage ◽  
Current Approach ◽  
Developmental Competence ◽  
Matrix Remodeling ◽  
Oocyte Competence ◽  
Nuclear Maturation ◽  
Oocyte Developmental Competence ◽  
Cumulus Oocyte Complex

Oocyte developmental competence is one of the determining factors that influence the outcomes of an IVF cycle regarding the ability of a female gamete to reach maturation, be fertilized, and uphold an embryonic development up until the blastocyst stage. The current approach of assessing the competency of an oocyte is confined to an ambiguous and subjective oocyte morphological evaluation. Over the years, a myriad of biomarkers in the cumulus-oocyte-complex has been identified that could potentially function as molecular predictors for IVF program prognosis. This review aims to describe the predictive significance of several cumulus-oocyte complex (COC) biomarkers in evaluating oocyte developmental competence. A total of eight acclaimed cumulus biomarkers are examined in the study. RT-PCR and microarray analysis were extensively used to assess the significance of these biomarkers in foreseeing oocyte developmental competence. Notably, these biomarkers regulate vital processes associated with oocyte maturation and were found to be differentially expressed in COC encapsulating oocytes of different maturity. The biomarkers were reviewed according to the respective oocyte maturation events namely: nuclear maturation, apoptosis, and extracellular matrix remodeling, and steroid metabolism. Although substantial in vitro evidence was presented to justify the potential use of cumulus biomarkers in predicting oocyte competency and IVF outcomes, the feasibility of assessing these biomarkers as an add-on prognostic procedure in IVF is still restricted due to study challenges.

scholarly journals Effect of varying glucose and glucosamine concentration in vitro on mouse oocyte maturation and developmental competence

2013 ◽  
Vol 25 (8) ◽  
pp. 1095 ◽  
Author(s):  
L. A. Frank ◽  
M. L. Sutton-McDowall ◽  
D. L. Russell ◽  
X. Wang ◽  
D. K. Feil ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Blastocyst Development ◽  
Oocyte Competence ◽  
Hexosamine Pathway ◽  
Hexosamine Biosynthesis ◽  
Necessary And Sufficient

The effects of hyper- and hypo-glycaemic conditions during the in vitro maturation of mouse cumulus–oocyte complexes on developmental competence were examined, with an emphasis on the role of the hexosamine biosynthesis pathway. A low (1 mM) glucose concentration achieved optimal oocyte competence (3-fold higher blastocyst development rate compared with high (30 mM) glucose, P < 0.05). In addition, glucose supplementation during only the first hour after release from the follicle was necessary and sufficient to support oocyte maturation and embryo development to the blastocyst stage. Glucosamine (a known hyperglycaemic mimetic and specific activator of the hexosamine pathway) was able to substitute for glucose during this first hour, indicating that flux through the hexosamine pathway is essential for oocyte competence. In the absence of glucose throughout the maturation period, glucosamine was not able to increase developmental competence, and at higher concentrations (2.5 and 5 mM) had a detrimental effect on MII and blastocyst development rates, compared with controls (P < 0.05). These experiments underscore the importance of glucose metabolic pathways during in vitro maturation and support the concept that excess flux through the hexosamine pathway has detrimental consequences.

266 Effects of Inflammatory States on Ovarian Biology and Oocyte Competence

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 134-135
Author(s):  
Jennifer A Hernandez Gifford ◽  
Emily Ferranti ◽  
Kylee Forrest ◽  
Craig A Gifford
Keyword(s):  
Granulosa Cell ◽  
Oocyte Maturation ◽  
Beta Catenin ◽  
Control Mechanisms ◽  
Steroid Production ◽  
Oocyte Competence ◽  
Nuclear Maturation ◽  
Naturally Occurring ◽  
Hormonal Milieu

Abstract Female fertility is dependent on estradiol concentrations which regulate a multitude of ovarian functions including follicle development and oocyte maturation leading to ovulation of a viable oocyte. Estradiol biosynthesis is regulated by coordinated actions of follicle-stimulating hormone and intra-ovarian control mechanisms including the co-transcription factor beta-catenin. Beta-catenin is a multi-faceted protein recognized for its role in granulosa cell steroid production and is shown to be modulated by lipopolysaccharide (LPS), the endotoxin responsible for stimulation of the immune system in infections caused by Gram-negative bacteria. Beef heifers treated with subacute concentrations of LPS during a synchronized follicular wave demonstrate a decline in serum estradiol concentrations 50 h after CIDR withdrawal, corresponding with dominant follicle maturation and preceding ovulation. The endotoxin exposure also resulted in increased LPS concentration and E2:P4 ratios in follicular fluid suggesting that low dose LPS modulates the intra-follicular hormonal milieu. Additionally, in a granulosa cell line, LPS treatment decreased mRNA expression of aromatase and beta-catenin. These data indicate that LPS alters E2 synthesis by modulating beta-catenin and subsequent steroidogenic enzyme expression. To further explore the contribution of naturally occurring LPS exposure on follicular steroid production and developing oocytes, bovine ovary pairs were collected from local abattoirs. Oocytes were aspirated from small follicles and matured in vitro to evaluate meiotic events related to nuclear maturation and spindle morphology. Small follicles from ovarian pairs were separated by the detectable LPS concentrations into high and low LPS groups. Oocytes matured from low LPS follicles demonstrated an increase in the percent of abnormal maturation events. Data indicate that induced or naturally occurring low doses of LPS can alter circulating and follicular estradiol concentrations impairing oocyte maturation. Perturbation to local ovarian signaling cascades from subclinical inflammatory disease may be an unappreciated factor altering fertility and leading to decreased cow retention.

scholarly journals Effect of Hyaluronan on Developmental Competence and Quality of Oocytes and Obtained Blastocysts fromIn VitroMaturation of Bovine Oocytes

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jolanta Opiela ◽  
Joanna Romanek ◽  
Daniel Lipiński ◽  
Zdzisław Smorąg
Keyword(s):  
Dna Fragmentation ◽  
Oocyte Maturation ◽  
Developmental Competence ◽  
Meiotic Maturation ◽  
Nuclear Maturation ◽  
Significant Difference ◽  
The Mean ◽  
Bovine Oocytes

The objective of the present study was to evaluate the effect of hyaluronan (HA) during IVM on meiotic maturation, embryonic development, and the quality of oocytes, granulosa cells (GC), and obtained blastocysts. COCs were maturedin vitroin control medium and medium with additional 0.035% or 0.07% of exogenous HA. The meiotic maturity did not differ between the analysed groups. The best rate and the highest quality of obtained blastocysts were observed when 0.07% HA was used. A highly significant difference (P<0.001) was noted in the mean number of apoptotic nuclei per blastocyst and in the DCI between the 0.07% HA and the control blastocysts (P<0.01). Our results suggest that addition of 0.035% HA and 0.07% HA to oocyte maturation media does not affect oocyte nuclear maturation and DNA fragmentation. However, the addition of 0.07% HA during IVM decreases the level of blastocysts DNA fragmentation. Finally, our results suggest that it may be risky to increase the HA concentration during IVM above 0.07% as we found significantly higherBaxmRNA expression levels in GC cultured with 0.07% HA. The final concentration of HA being supplemented to oocyte maturation media is critical for the success of the IVP procedure.

327 OOCYTE-SECRETED FACTORS DIRECTLY AFFECT OOCYTE DEVELOPMENTAL COMPETENCE DURING IN VITRO MATURATION OF THE BOVINE CUMULUS - OOCYTE COMPLEX

2006 ◽  
Vol 18 (2) ◽  
pp. 271 ◽  
Author(s):  
T. S. Hussein ◽  
R. B. Gilchrist ◽  
J. G. Thompson
Keyword(s):  
In Vitro Maturation ◽  
Cumulus Cell ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Bovine Oocyte ◽  
Paracrine Factors ◽  
Cell Functions ◽  
Oocyte Developmental Competence ◽  
Secreted Factors

Paracrine factors secreted by the oocyte (oocyte-secreted factors, OSFs) regulate a broad range of cumulus cell functions including proliferation, differentiation, and apoptosis. The capacity of oocytes to regulate their own microenvironment by OSFs may in turn contribute to oocyte developmental competence. The aim of this study was to determine if OSFs have a direct influence on bovine oocyte developmental competence during in vitro maturation (IVM). Cumulus-oocyte complexes (COCs) were obtained by aspiration of >3-mm follicles from abattoir-derived ovaries. IVM was conducted in Bovine VitroMat (Cook Australia, Eight Mile Plains, Brisbane, Australia) supplemented with 0.1 IU/mL rhFSH for 24 h under 6% CO2 in air at 38.5�C. In the first experiment, COCs were co-cultured with denuded oocytes (DOs, 5/COC in 10 �L) beginning at either 0 or 9-h of IVM. To generate the 9-h DO group, COCs were first cultured intact for 9-h and then denuded. In the second experiment, specific OSFs, recombinant bone morphogenetic protein-15 (BMP-15) and growth differentiation factor 9 (GDF-9), were prepared as partially purified supernatants of transfected 293H cells, and used as 10% v/v supplements in Bovine VitroMat. Treatments were: (1) control (no supplement), (2) BMP-15, (3) GDF-9, (4) BMP-15 and GDF-9, and (5) untransfected 293H control. Following maturation, in vitro production of embryos was performed using the Bovine Vitro system (Cook Australia) and blastocysts were examined on Day 8 for development. Developmental data were arcsine-transformed and analyzed by ANOVA, followed by Tukey's test. Cell numbers were analyzed by ANOVA. Co-culturing intact COCs with DOs from 0 or 9 h did not affect cleavage rate, but increased (P < 0.001) the proportion of cleaved embryos that reached the blastocyst stage post-insemination (50.6 � 1.9 and 61.3 � 1.9%, respectively), compared to COCs cultured alone (40.7 � 1.4%). Therefore, paracrine factors secreted by DOs increased the developmental competence of oocytes matured as COCs. OSFs also improved embryo quality, as co-culture of COCs with DOs (0 or 9 h) significantly increased total cell (156.1 � 1.3 and 159.1 � 1.3, respectively) and trophectoderm (105.7 � 1.3 and 109.8 � 0.4, respectively) numbers, compared to control COCs (total = 148 � 1.2, trophectoderm = 98.2 � 0.8, P < 0.001). BMP-15 alone or with GDF-9 also significantly (P < 0.001) increased the proportion of oocytes that reached the blastocyst stage post insemination (57.5 � 2.4% and 55.1 � 4.5%, respectively), compared to control (41.0 � 0.9%) and 293H-treated (27.1 � 3.1%) COCs. GDF-9 also increased blastocyst yield (49.5 � 3.9%) but not significantly. These results are the first to demonstrate that OSFs, and particularly BMP-15 and GDF-9, directly affect bovine oocyte developmental competence. These results have far-reaching implications for improving the efficiency of IVM in domestic species and human infertility treatment, and support the role of OSF production by oocytes as a diagnostic marker for developmental competence.

246 IN VITRO PRODUCTION OF SPRINGBOK (ANTIDORCAS MARSUPIALIS) EMBRYOS

2007 ◽  
Vol 19 (1) ◽  
pp. 239 ◽  
Author(s):  
R. Krisher ◽  
A. Auer ◽  
K. Clark ◽  
K. Emsweller ◽  
S. Rogers ◽  
...  
Keyword(s):  
South Africa ◽  
Oocyte Maturation ◽  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Genetic Management ◽  
Blastocyst Development ◽  
Antidorcas Marsupialis

The objective of this experiment was to develop in vitro embryo production (IVP) technologies in springbok (Antidorcas marsupialis), a southern African antelope. Springbok, a fairly common species on game farms in parts of South Africa, may be used as a model species for gamete rescue and IVP techniques to be applied to the conservation of other threatened antelope species. Springbok belong to the family bovidae, subfamily antilopinae, tribe antilopini, which comprises about twenty species in genera Gazella, Antilope, Procapra, Antidorcas, Litocranius, and Ammodorcas. In this tribe alone, there are 4 species or subspecies that are critically endangered, 3 that are endangered, and 10 that are considered vulnerable, demonstrating the need for antelope conservation efforts. In addition, our studies contributed to the South African biological resource bank, so that banked springbok semen and embryos might be used in the future for managed genetic contribution to isolated captive or wild populations via assisted reproductive technologies. Oocytes were recovered (3 replicates) from ovaries obtained at supervised culls for management purposes in South Africa, and cultured in defined Gmat or undefined TCM-199 with FCS maturation medium for 28-30 h (Brad et al. 2004 Reprod. Fertil. Dev. 16, 223). Oocytes were fertilized with frozen-thawed springbok epididymal spermatozoa in modified SOF fertilization medium with caffeine (Herrick et al. 2004 Biol. Reprod. 71, 948–958). Eighteen hours after insemination, a randomly selected subset of the zygotes were fixed to determine fertilization success. The remaining zygotes were cultured in G1/G2 media. On Day 7 of culture, embryos were analyzed for development to the morula or blastocyst stage. A total of 259 selected oocytes were collected from 50 females (5.2 selected oocytes/female on average). There was no difference in the percentage of oocytes normally fertilized (2 pronuclei, PN) between oocytes matured in Gmat (n= 43; 12%) and those matured in TCM-199 (n= 42; 10%). There were significantly (P &lt; 0.05) more oocytes penetrated (e2 PN) when matured in TCM (50%) compared to Gmat (23%). There were no differences in embryonic cleavage or morula/blastocyst development (of total oocytes inseminated) between treatments (Gmat,n= 89, 54%, 9.0%; TCM-199, n= 85, 68%, 9.4%, respectively). In both treatments, the average blastocyst grade was 2.125 using the standard bovine grading system (Curtis, Cattle Embryo Transfer Procedure, 1991). In conclusion, in vitro oocyte maturation, fertilization, and embryo culture to the blastocyst stage is possible in springbok. Importantly, blastocysts can be produced in vitro under semi-defined conditions, demonstrating that oocyte maturation without serum does support developmental competence. This is important for the potential international movement of IVP embryos to be used for genetic management in the conservation of antelope species.

172 DETERMINING THE REQUIREMENTS FOR LH AND FSH DURING SHEEP IN VITRO OOCYTE MATURATION

2014 ◽  
Vol 26 (1) ◽  
pp. 200 ◽  
Author(s):  
C. de Frutos ◽  
R. Vicente-Perez ◽  
P. J. Ross
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Mixed Logit ◽  
Cumulus Cells ◽  
Pituitary Hormones ◽  
Developmental Competence ◽  
Cumulus Expansion ◽  
Nuclear Maturation ◽  
Grade 3

In vitro maturation (IVM) of oocytes in domestic animals is a widespread practice of research and commercial relevance. Gonadotropic hormones are typically supplemented to the IVM medium to stimulate resumption of meiosis, progression to metaphase II (MII), and oocyte developmental competence. The common use of pituitary-derived products presents 2 problems: contamination from other pituitary hormones and inconsistences from batch-to-batch variation. Recombinant hormones can help circumvent these issues and identify specific gonadotropin requirements for in vitro maturation. The aim of the present study was to determine the effect of supplementing recombinant bovine LH and/or FSH (AspenBio) to the maturation of ovine oocytes in terms of cumulus expansion and progression to the MII stage. Abattoir-derived sheep cumulus–oocyte complexes (COC) were obtained from 1- to 5-mm-diameter antral follicles by ovary slicing. Oocytes with a homogeneous cytoplasm surrounded by at least 3 layers of cumulus cells were selected and cultured in serum-free IVM medium (Cotterill et al. 2012 Reproduction 144, 195–207) at 38.5°C and 5% CO2. The COC obtained from 8 replicates were allocated into 4 experimental groups: (1) no hormones; (2) 1.5 μg mL–1 recombinant bovine LH (rbLH); (3) 1.5 μg mL–1 recombinant bovine FSH (rbFSH); and (4) rbLH and rbFSH. The expansion of cumulus cells was recorded in each group after 24 h of IVM and COC classified as (1) very poor or no cumulus expansion (grade 1); (2) limited cumulus expansion (grade 2); and (3) full cumulus expansion (grade 3). Nuclear maturation in the 4 treatments was evaluated by assessing progression to the MII stage via DNA staining with Hoechst 33342 and fluorescence imaging. The effect of treatment on the observed proportion of MII oocytes was evaluated using a mixed logit model including treatment and replicate as fixed and random effects, respectively. Culture in IVM medium in the absence of gonadotropins or in the presence of rbLH resulted in poor cumulus expansion (grade 1). The supplementation of IVM medium with rbFSH (with or without rbLH) yielded a high degree of cumulus expansion (grades 2–3). Likewise, addition of rbFSH enhanced progression of oocytes to the MII stage, whereas use of rbLH, although it had an effect on progression to MII, did not augment the effect of rbFSH (Table 1). These results indicate that rbFSH is necessary and sufficient to induce sheep oocyte maturation in a high proportion of oocytes. Table 1.Cumulus expansion and oocyte nuclear stage after IVM

The effect of FF-MAS on porcine cumulus–oocyte complex maturation, fertilization and pronucleus formation in vitro

Zygote ◽  
2006 ◽  
Vol 14 (3) ◽  
pp. 189-199 ◽  
Author(s):  
Inger Faerge ◽  
Frantisek Strejcek ◽  
Jozef Laurincik ◽  
Detlef Rath ◽  
Heiner Niemann ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Follicular Fluid ◽  
Developmental Potential ◽  
Nuclear Maturation ◽  
Cumulus Oocyte Complex ◽  
Constant Ph ◽  
Porcine Oocyte ◽  
Fine Glass ◽  
Epidermal Growth

SummaryFollicular fluid meiosis-activating sterol (FF-MAS) has been isolated from the follicular fluid (FF) of several species including man. FF-MAS increases the quality of in vitro oocyte maturation, and thus the developmental potential of oocytes exposed to FF-MAS during in vitro maturation is improved. The aim of the present study was to investigate the effects of FF-MAS on porcine oocyte maturation and pronucleus formation in vitro. Porcine cumulus–oocyte complexes (COCs) were isolated from abattoir ovaries and in vitro matured for 48 h in NCSU 37 medium supplemented with 1 mg/l cysteine, 10 ng/ml epidermal growth factor and 50 μM 2-mercaptoethanol with or without 10% porcine follicular fluid (pFF). For the first 22 h, 1 mM db-cAMP and 10 I.E PMSG/hCG was added. The medium was supplemented with 1 μM, 3 μM, 10 μM, 30 μM or 100 μM FF-MAS dissolved in ethanol. After maturation the COCs were denuded mechanically using a fine glass pipette under constant pH and in vitro fertilized with fresh semen (5 × 105 spermatozoa/ml). The presumptive zygotes were evaluated 18 h after fertilization. The addition of pFF increased the monospermic as well as the polyspermic penetration of oocytes. In the absence of pFF, the addition of FF-MAS decreased the polyspermic penetration rate, whereas FF-MAS in combination with pFF decreased monospermic and increased polyspermic penetration. The degeneration rate of ova decreased in the presence of FF-MAS irrespective of the presence or absence of pFF. In the absence of pFF, FF-MAS at 3–10 μM increased the number of zygotes with advanced maternal pronuclear stages. In supraphysiological doses, i.e. 30–100 μM, FF-MAS dose-dependently and reversibly inhibited nuclear maturation in the absence of pFF.

scholarly journals Effect of epidermal growth factor-like peptides on pig cumulus cell expansion, oocyte maturation, and acquisition of developmental competence in vitro: comparison with gonadotropins

Reproduction ◽  
2011 ◽  
Vol 141 (4) ◽  
pp. 425-435 ◽  
Author(s):  
Radek Procházka ◽  
Michal Petlach ◽  
Eva Nagyová ◽  
Lucie Němcová
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Oocyte Maturation ◽  
Cumulus Cell ◽  
Cumulus Cells ◽  
Blastocyst Stage ◽  
Human Chorionic Gonadotrophin ◽  
Developmental Competence ◽  
Epidermal Growth

The aim of this work was to assess the FSH-stimulated expression of epidermal growth factor (EGF)-like peptides in cultured cumulus–oocyte complexes (COCs) and to find out the effect of the peptides on cumulus expansion, oocyte maturation, and acquisition of developmental competencein vitro. FSH promptly stimulated expression of amphiregulin (AREG) and epiregulin (EREG), but not betacellulin (BTC) in the cultured COCs. Expression ofAREGandEREGreached maximum at 2 or 4 h after FSH addition respectively. FSH also significantly stimulated expression of expansion-related genes (PTGS2,TNFAIP6, andHAS2) in the COCs at 4 and 8 h of culture, with a significant decrease at 20 h of culture. Both AREG and EREG also increased expression of the expansion-related genes; however, the relative abundance of mRNA for each gene was much lower than in the FSH-stimulated COCs. In contrast to FSH, AREG and EREG neither stimulated expression ofCYP11A1in the COCs nor an increase in progesterone production by cumulus cells. AREG and EREG stimulated maturation of oocytes and expansion of cumulus cells, although the percentage of oocytes that had reached metaphase II was significantly lower when compared to FSH-induced maturation. Nevertheless, significantly more oocytes stimulated with AREG and/or EREG developed to blastocyst stage after parthenogenetic activation when compared to oocytes stimulated with FSH alone or combinations of FSH/LH or pregnant mares serum gonadotrophin/human chorionic gonadotrophin. We conclude that EGF-like peptides do not mimic all effects of FSH on the cultured COCs; nevertheless, they yield oocytes with superior developmental competence.

296 IMPACT OF CO-CULTURING CUMULUS-ENCLOSED PORCINE OOCYTES WITH DENUDED OOCYTES DURING IN VITRO MATURATION IN A DEFINED MEDIUM ON CUMULUS EXPANSION AND OOCYTE MATURATION

2015 ◽  
Vol 27 (1) ◽  
pp. 237
Author(s):  
R. Appeltant ◽  
T. Somfai ◽  
M. Nakai ◽  
S. Bodo ◽  
D. Maes ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Binary Logistic Regression ◽  
Defined Medium ◽  
Positive Influence ◽  
Developmental Competence ◽  
Cumulus Expansion ◽  
Nuclear Maturation ◽  
Morphological Criteria

Recent research has revealed that oocyte-secreted factors (OSF) affect cumulus expansion and play important roles during maturation and embryo development of mammalian oocytes. The use of denuded oocytes (DO) as supplements during in vitro maturation (IVM) in a nondefined medium improved developmental competence of cumulus-enclosed porcine oocytes (COC; Gomez et al. 2012 Zygote 20, 135–145). We investigated the effect of DO on cumulus expansion and nuclear maturation of COC in pigs during IVM using a defined medium. If the DO exert a positive influence on IVM, the defined medium can then be analysed for the presence of OSF. Immature COC were collected in the slaughterhouse from prepubertal gilts. To obtain DO, some COC were completely denuded by pipetting through a narrow-bore glass pipette. The COC used as a source for DO fulfilled the same morphological criteria as the COC used for IVM. The IVM medium was porcine oocyte medium (POM; Yoshioka et al. 2008 J. Reprod. Dev. 54, 208–213) with hormone supplementations applied only during the first 20 h of the IVM period. The COC were fixed to the bottom of 35-mm plastic Petri dishes in 3 × 3 grids by Cell-Tak (BD Bioscience, Bedford, MA, USA) in 100-µL droplets POM covered by paraffin oil. Culture droplets (each including 1 COC grid) were supplemented with (DO+ group, n = 179) or without 16 DO (DO– group, n = 143). After 20 h of IVM, the medium was replaced with a preincubated hormone-free POM and oocytes were cultured for an additional 28 h. At 0, 20, and 48 h of IVM, images of each grid were taken at the same magnification. The size of each COC was measured as a 2-dimensional area in pixels by analysing images with ImageJ software. Relative cumulus expansion was calculated at 20 and 48 h of IVM on the basis of the initial COC size at 0 h, which was assigned as 1. At 48 h of IVM, the COC were denuded and examined for oocyte maturation by orcein staining. The experiment was replicated 5 times. Cumulus expansion ratios at 20 and 48 h of IVM were compared between the DO+ and DO– groups by ANOVA. Maturation rates were compared between the DO+ and DO– groups by binary logistic regression. No difference in cumulus expansion between DO– and DO+ could be observed at 20 h (1.83 ± 0.04 and 1.75 ± 0.03, respectively) and 48 h (1.41 ± 0.03 and 1.47 ± 0.02, respectively) of IVM. Nuclear maturation rates of COC in DO– and DO+ groups did not differ significantly (39.0 ± 5.4 and 32.9 ± 8.8%, respectively). In conclusion, addition of DO to the defined IVM medium did not affect the cumulus expansion and oocyte maturation of follicular porcine COC. Further research is needed to assess the effects of DO during IVM on subsequent fertilization. If DO prove to be beneficial for fertilization, the nature of the OSF will be investigated.This study was supported by FCWO of UGent and by FWO-Flanders (grant number FWO11/ASP/276).

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.

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