Evaluation of the simulated physiological oocyte maturation (SPOM) system on F1 Gyr × Holstein oocytes and embryos

2019 ◽  
Vol 59 (4) ◽  
pp. 634 ◽  
Author(s):  
Gabriela Ramos Leal ◽  
Clara Ana dos Santos Monteiro ◽  
Helena Fabiana Reis de Almeida Saraiva ◽  
Agostinho Jorge dos Reis Camargo ◽  
André Luís Rios Rodrigues ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
The Other ◽  
Production Rates ◽  
Meiotic Arrest ◽  
Embryo Production ◽  
Commercial Medium ◽  
Number Of Cells

The present study aimed to evaluate the effect of the simulated physiological oocyte maturation (SPOM) system on F1 Gyr × Holstein oocytes and embryos by evaluating the meiotic arrest, embryo production rates, total number of cells and lipid score. Three experiments were conducted and the following three experimental groups were formed according to in vitro maturation (IVM) treatments: CONTROL 1 (TCM 199 medium without FBS), CONTROL 2 (commercial medium) and SPOM (TCM 199 medium with forskolin and 3-isobutyl-1-methylxanthine (IBMX) in pre-IVM and extended IVM with cilostamide). In the first experiment (ovum pick-up), a significant (P < 0.05) reduction in the percentage of matured oocytes in SPOM group was observed. In the second (slaughterhouse ovaries) and third (ovum pickup) experiments, the cleavage and blastocyst rates were reduced (P < 0.05) in the SPOM group. There was no significant (P > 0.05) difference in total number of cells among the groups. No difference (P > 0.05) was found on lipid score among the groups at Day 7 of development, in both Experiments 2 and 3. At Day 9 (Experiment 2), only the CONTROL 2 showed a significant increase (P > 0.05) compared with the other treatments. It was concluded that under our conditions, the SPOM system was efficient in prolonging meiotic arrest on Gyr × Holstein oocytes, offering the oocytes in vitro conditions more similar to those found in vivo; however, it adversely affected embryo production rates and promoted no beneficial effect on the total number of cells and the lipid score.

P–442 Cancer does not adversely affect oocyte maturation in vitro with the exception of breast cancer

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
I Viran. . Klun ◽  
J Bedenk ◽  
N Jancar
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Hormonal Stimulation ◽  
Infertile Women ◽  
Maturation In Vitro ◽  
Infertile Patients

Abstract Study question Do different types of cancer affect the success of oocyte maturation in vitro compared to infertile women included in the in vitro fertilization (IVF) program? Summary answer Cancer does not adversely affect oocyte maturation in vitro, with the exception of breast cancer, compared to infertile women in the in vitro fertilization program. What is known already Vitrification and storage of oocytes in liquid nitrogen is one of the real options for maintaining reproductive function in cancer patients. Despite careful hormonal stimulation of the ovaries, however, the proportion of oocytes is immature and lost to the patient. In vitro maturation of oocytes can play an important role in resolving immature oocytes and increasing the chances of conception in cancer patients. Moreover, it can mean a safe way to store oocytes when ovarian hormonal stimulation could worsen the disease. Therefore, the aim of this study was to determine whether different types of cancer affect oocyte in vitro maturation. Study design, size, duration After ovarian stimulation in 18 cancer patients, the number and maturity of oocytes were compared to 21 infertile patients in the IVF program over a three-year period. In both groups, 119 germinal vesicle-GV oocytes were matured in vitro to compare the maturation rate. After IVF in a subset of 17 infertile patients, the fertilization of in vitro and in vivo matured oocytes was compared in the same cycles. The procedure was considered in cancer patients. Participants/materials, setting, methods In this prospective study, forty-five GV oocytes in cancer patients and 74 GV oocytes in infertile patients underwent in vitro maturation procedure. Each oocyte was matured in vitro in the MediCult IVM System by conditioning in LAG medium and maturation for up to 28 hours in IVM medium with added hormones FSH and hCG, in coculture with cumulus cells from mature oocytes in the same patients. Oocytes were fertilized by intracytoplasmic sperm injection (ICSI). Main results and the role of chance After controlled ovarian hormonal stimulation, 198 oocytes were retrieved in cancer patients and 259 oocytes in infertile women and there were no significant differences in the number of retrieved oocytes, proportion of degenerated oocytes and proportion of GV oocytes. In cancer patients, the proportion of oocytes that matured in vitro was lower than in infertile patients (66.0 vs. 80.0%), but the difference was not significant. Among cancer patients, the oocyte maturation rate tended to be lower in patients with breast cancer than in patients with other cancers (54.5% vs. 81.2%; difference not significant). However, in patients with breast cancer, significantly fewer oocytes matured in vitro than in infertile patients (54.5% vs. 80.0%; P < 0.05, Chi-Square test) even though they tended to be younger (29.3 ± 7.4 vs. 33.4 ± 5.0 years; non-significant difference). After in vitro maturation, there was a 13% increase in mature oocyte yield in cancer patients and a 20.1% increase in infertile women with no significant difference observed. After ICSI in a subset of infertile women, there was approximately the same fertilization rate between oocytes matured in vitro and in vivo (55.1% vs. 57.0%) in the same cycles. Limitations, reasons for caution For ICSI in oocytes matured in vitro, we had to use semen collected the day before, while oocytes matured in vivo were fertilized with fresh semen in the same cycle. Therefore, we could not compare the development of embryos in both groups. Wider implications of the findings: In vitro maturation of oocytes in connection with their vitrification or vitrification of embryos after their fertilization appears to be a valuable way to maintain the fertility of young cancer patients, but a worse outcome is expected in breast cancer patients. Trial registration number National Medical Ethical Committee Approval, No. 0120–222/2016–2; KME 115/04/16.

188 IMPROVEMENT OF IN VITRO CANINE OOCYTE MATURATION BY OVIDUCTAL SECRETOME

2017 ◽  
Vol 29 (1) ◽  
pp. 202 ◽  
Author(s):  
A. Lange-Consiglio ◽  
C. Perrini ◽  
P. Esposti ◽  
F. Cremonesi
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Cumulus Cell ◽  
Follicular Development ◽  
Cumulus Cells ◽  
Chi Square ◽  
Cell Layers ◽  
Hoechst Staining

The in vitro maturation of canine oocyte is problematic because it is difficult to reproduce the oviducal microenvironment where the in vivo maturation occurs. Because cells are able to communicate with each other by paracrine action, oviducal cells could be in vitro cultivated to obtain the conditioned medium (CM) consisting of soluble factors and microvesicles (MV), which represent a carrier for nonsoluble molecules including microRNA. The aim of the present work was to investigate the effect of the addition of CM or MV, secreted by oviducal cells, to the canine in vitro maturation medium. To generate CM, cells from oviducts of 3 animals in late oestrus were cultured for 5 days at 38.5°C in a humidified atmosphere of 5% CO2. Supernatants were collected, pooled, centrifuged at 2500 × g, and stored at −80°C. Microvesicles were obtained by ultracentrifugation of CM at 100,000 × g for 1 h at 4°C and measured for concentration and size by a Nanosight instrument. Ovaries were obtained from 50 healthy domestic bitches (1–4 years old) of different breeds that underwent ovariectomy regardless of the oestrous cycle. Cumulus-oocyte complexes were released by slicing the ovarian cortex with a scalpel blade, and only Grade 1 cumulus-oocyte complexes (darkly granulated cytoplasm and surrounded by 3 or more compact cumulus cell layers) 110 to 120 µm in diameter were selected for culture. Maturation was performed at 38.5°C in a humidified atmosphere of 5% CO2 and 5% of O2 in bi-phasic systems: 24 h in SOF with 5.0 μg mL−1 of LH followed by 48 h in SOF supplemented with 10% of oestrous bitch serum and 10% CM or 50, 75, 100, or 150 × 106 MV mL−1 labelled with PKH-26. Control was the same medium without CM or MV. Oocytes were observed under a fluorescent microscope to detect metaphase II (MII), by Hoechst staining, and the incorporation of MV. Statistical analysis was performed by chi-square test. Results show that canine oviducal cells secreted MV of 234 ± 23 nm in size, underling that these MV fall within the shedding vesicles category. The incorporation of labelled MV occurred at first in cumulus cells, at 48 h of maturation, and then, at 72 h, in oocyte cytoplasm. These MV had a positive effect on maturation rate (MII) at the concentration of 75 and 100 × 106 MV mL−1 compared with CM and control (20.34 and 21.82 v. 9.09 and 3.95%, respectively). The concentration of 150 × 106 MV mL−1 provided only 9.26% of MII. To understand the role of MV, we assessed the expression of 3 microRNA (miRNA-30b, miR-375, and miR-503) that are involved in some key pathways (WNT, MAPK, ERbB, and TGFβ) regulating follicular development and meiotic resumption. The lower rate of MII with the higher concentration of MV is possibly due to the high level of miR-375, which recent literature shows to suppress the TGFβ pathway, leading to impaired oocyte maturation. In conclusion, the oviducal MV, or specific microRNA, are involved in cellular trafficking during oocyte maturation, and their possible use in vitro could facilitate the exploitation of canine reproductive biotechnologies.

191 IN VITRO CULTURE DURING OOCYTE MATURATION AND FERTILIZATION INFLUENCES THE TRANSCRIPTOME PROFILES OF BOVINE BLASTOCYSTS

2015 ◽  
Vol 27 (1) ◽  
pp. 186
Author(s):  
A. Gad ◽  
U. Besenfelder ◽  
V. Havlicek ◽  
M. Hölker ◽  
F. Rings ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Oocyte Maturation ◽  
Microarray Data ◽  
In Vitro Maturation ◽  
Culture Conditions ◽  
Control Group ◽  
Bovine Embryos ◽  
Vitro Fertilization

Early embryonic development, the period from oocyte maturation until blastocyst formation, is the most critical period of mammalian development. It is well known that in vitro maturation, fertilization, and culture of bovine embryos is highly affected by culture conditions. However, the stage-specific effect of culture environment is poorly understood. Therefore, we aimed to examine the effect of in vitro culture conditions during oocyte maturation and fertilization on the transcriptome profile of the resulting blastocysts. Bovine oocytes were matured in vitro and then either directly transferred to synchronized recipients, fertilized, and cultured in vivo (Vitro_M), or transferred after in vitro fertilization (Vitro_F), or at zygote stage (Vitro_Z) and blastocysts were collected at Day 7 by uterine flushing. For in vivo or in vitro fertilization, the same frozen-thawed commercial bull semen has been used. Complete in vitro (IVP) and in vivo produced blastocysts were used as controls. Gene expression patterns between each blastocyst group and in vivo produced blastocyst group were compared using EmbryoGENE's bovine microarray (EmbryoGENE, Québec, QC, Canada) over six replicates of each group (10 blastocyst/replicate). Microarray data were statistically analysed using the Linear Models for Microarray Data Analysis (LIMMA) package under the R program (The R Project for Statistical Computing, Vienna, Austria). Results showed that, the longer the embryos spent under in vitro conditions, the higher was the number of differentially expressed genes (DEG, fold-change = 2 with adjusted P-value = 0.05) compared with in vivo control group. The Vitro_M group showed the lowest number of DEG (149); in contrast IVP group represented 841, DEG, respectively compared to in vivo control group. Ontological classification of DEG showed that lipid metabolism was the most significant function influenced by in vitro maturation conditions. More than 55% of DEG in the Vitro_M group were involved in the lipid metabolism process and most of them showed down-regulation compared to in vivo control group. On the other hand, Vitro_F and Vitro_Z groups showed nearly similar numbers of DEG (584 and 532, respectively) and the majority of these genes in both groups were involved in cell-death- and cell-cycle-related functions. Pathway analysis revealed that retinoic acid receptor activation pathways were the common ones in the Vitro_M and Vitro_F groups. However, different signalling pathways were commonly dominant in the Vitro_F and Vitro_Z groups. This study provides the transcriptome elasticity of bovine embryos exposed to different environments during maturation, fertilization, and culture periods of development.

Effect of administering a crude equine gonadotrophin preparation to mares on follicular development, oocyte recovery rate and oocyte maturation in vivo

Reproduction ◽  
2000 ◽  
pp. 351-360 ◽  
Author(s):  
I Bruck ◽  
J Bezard ◽  
M Baltsen ◽  
B Synnestvedt ◽  
I Couty ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Recovery Rate ◽  
In Vitro Maturation ◽  
Follicular Development ◽  
Vitro Fertilization ◽  
Nuclear Maturation ◽  
Oocyte Yield ◽  
Oocyte Recovery

In mares, the shortage of oocytes and the variability in nuclear maturation at a certain time of the oestrous cycle hinders the optimization of methods for in vitro maturation and in vitro fertilization. Increasing the number of small-to-medium-sized follicles available for aspiration in vivo may increase the overall oocyte yield. The aims of the present study were to investigate whether administration of crude equine gonadotrophins affects follicular development, oocyte recovery rate, in vivo oocyte maturation and follicular concentrations of meiosis-activating sterols. During oestrus, all follicles >/= 4 mm were aspirated from 19 pony mares (first aspiration: A1). Over the next 8 days, the mares were treated daily with either 25 mg crude equine gonadotrophins (n = 10) or physiological saline (n = 9). Between day 1 and day 8, follicular growth was monitored by ultrasonography. On day 8, all follicles >/= 4 mm were evacuated (second aspiration: A2) and nuclear maturation of the recovered oocytes was assessed after orcein staining. Follicular growth between A1 and A2, as well as the number and size of follicles at A2 were similar for control mares and mares treated with crude equine gonadotrophins. The oocyte recovery rates at A1 and A2 were similar. At A2, the oocyte recovery rate and oocyte maturation in vivo were not affected by treatment with crude equine gonadotrophins. The number of expanded cumulus oophorus complexes recovered from follicles </= 29 mm was significantly higher at A1 than at A2. The number of oocytes at the germinal vesicle stage was significantly higher at A2 (41.5%) than at A1 (17.8%). Meiosis-activating sterols (FF-MAS and T-MAS) were identified in follicular fluid recovered at A2. Follicular concentrations of FF-MAS and T-MAS were unaffected by treatment with crude equine gonadotrophins. The present study demonstrates that follicular aspiration during oestrus allowed a new follicular population to develop and resulted in a higher degree of synchronization of oocyte development with respect to cumulus expansion and nuclear maturation. The availability of a more homogeneous population of oocytes might facilitate a better optimization of in vitro maturation and in vitro fertilization techniques in mares. Administration of crude equine gonadotrophins during early dioestrus did not affect the growth of small follicles, the oocyte yield after aspiration or oocyte maturation in vivo.

Influence of vasoactive intestinal peptide (VIP), atrial natriuretic peptide (ANP) and insulin-like growth factor-I (IGF-I) on in vitro maturation of prepubertal and adult sheep oocytes

Zygote ◽  
1996 ◽  
Vol 4 (04) ◽  
pp. 343-348 ◽  
Author(s):  
S. Ledda ◽  
L. Bogliolo ◽  
G. Leoni ◽  
P. Calvia ◽  
S. Naitana
Keyword(s):  
Growth Factor ◽  
Atrial Natriuretic Peptide ◽  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Optimal Conditions ◽  
Factor I ◽  
Igf I

Much effort has been focused on establishing optimal conditions for obtainingin vitromaturation of oocytes from different species with results comparable to those achieved afterin vivodevelopment (reviewed by Brackett, 1992). However, even though extraordinary progress has been made, thein vitrotechnology for oocyte maturation lags far behind thatin vivoand improvements are needed to increase the quantity and quality of the embryos produced from these matured oocytes.

6 EXPRESSION PROFILING OF SINGLE BOVINE EMBRYOS REVEALS SIGNIFICANT EFFECTS OF IN VITRO MATURATION, FERTILIZATION AND CULTURE

2006 ◽  
Vol 18 (2) ◽  
pp. 111
Author(s):  
S. L. Smith ◽  
L.-Y. Sung ◽  
R. Page ◽  
B. Henderson ◽  
F. Du ◽  
...  
Keyword(s):  
Gene Expression ◽  
Differentially Expressed Genes ◽  
Oocyte Maturation ◽  
Expression Profiling ◽  
Bovine Serum ◽  
In Vitro Maturation ◽  
Differentially Expressed ◽  
In Vitro Oocyte Maturation

Cattle and sheep embryos transferred after in vitro production are often afflicted by large offspring syndrome (LOS), which has been correlated with the presence of serum and/or cell co-culture. Previous research indicates that post-fertilization culture affects blastocyst quality and gene expression, and in vitro oocyte maturation and fertilization impact developmental competence. To dissect the effects of in vitro maturation, fertilization, and culture, we compared the expression profiles of single bovine blastocysts generated by: (1) in vitro maturation, fertilization and culture (IVF, n = 15); (2) in vivo maturation, in vivo fertilization, and in vitro culture (IVD, n = 14); and (3) in vivo maturation, fertilization, and development (AI, n = 14). For in vitro culture, the embryos were cultured for 2 days in CR1aa medium with bovine serum albumin (BSA) and then transferred to CR1aa with 10% fetal bovine serum (FBS) with cumulus cells until Day 7, at which time the embryos were vitrified. IVD zygotes were surgically collected from two superovulated Holstein donor cows 24 h post-insemination and cultured in the same system. To conduct expression profiling, total RNA was isolated from individual thawed embryos. The RNA was subjected to three rounds of amplification utilizing a previously adapted and validated T7 linear amplification protocol. Amplified RNA from each embryo and from a standard reference was indirectly labeled with Cy3 or Cy5 by dye swap and hybridized to a custom bovine cDNA microarray containing ~6300 unique genes. After Loess normalization, an ANOVA model (GeneSpring 6.1 and SAS 9.0) was used to identify differentially expressed genes. The P-values were adjusted for multiple comparisons using the false discovery rate approach, and a e2-fold differential criterion was applied. A subset of the differentially expressed genes was verified by real-time RT-PCR. The blastocyst rates for IVF and IVD embryos were 37% and 75%, respectively. There were 305, 365, and 200 genes differentially expressed between the AI and IVD, the IVF and IVD, and the AI and IVF comparisons, respectively. Interestingly, 44 differentially expressed genes were identified between the AI embryos and both the IVF and the IVD embryos, making these potential candidates for LOS. There were 61 genes differentially expressed between the IVF embryos and the AI and IVD embryos. The Gene Ontology categories 'RNA processing' and 'RNA binding' were over-represented among the genes that were down-regulated in the IVF embryos, indicating an effect of in vitro oocyte maturation/fertilization on embryonic gene expression. This work was supported by USDA grants to X.Y., H.A.L., and X.C.T.

272 A NEW APPROACH TO IN VITRO MATURATION (IVM) AND EMBRYO IN VITRO PRODUCTION: INDUCED IVM SUBSTANTIALLY IMPROVES EMBRYO YIELD AND PREGNANCY OUTCOMES

2010 ◽  
Vol 22 (1) ◽  
pp. 293
Author(s):  
R. B. Gilchrist ◽  
F. K. Albuz ◽  
J. G. Thompson
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Cumulus Cell ◽  
In Vitro Production ◽  
New Approach ◽  
Fetal Survival ◽  
Wide Range ◽  
Vitro Production

Oocyte in vitro maturation (IVM) is the rate-limiting step in the in vitro production (IVP) of embryos. Oocyte maturation in vivo is a highly orchestrated, induced process, whereby cAMP-mediated meiotic arrest is overridden by the gonadotrophin surge prior to ovulation. However, aspirated oocytes resume maturation spontaneously compromising developmental competence. Hence, we hypothesized that establishing an induced system in vitro would synchronize oocyte-somatic cell communication leading to improved oocyte quality. Abattoir-collected bovine or 129/Sv mouse oocytes were treated for the first 1 to 2 h in vitro (pre-IVM) with the adenylate cyclase activator forskolin (100 μM, 50 μM, respectively) and a nonspecific phosphodiesterase (PDE) inhibitor, IBMX (500 μM, 50 μM), which substantially increased cumulus-oocyte complex (COC) cAMP (bovine, 180 v. 2 fmol/COC, treated v. control; P < 0.001). To maintain oocyte cAMP levels and prevent precocious oocyte maturation, IVM media (VitroMat + BSA) contained an oocyte-specific (type 3) PDE inhibitor, cilostamide (20 μM, 0.1 μM), plus FSH to induce maturation. The net effect of this system (induced-IVM) was to increase oocyte-cumulus cell gap-junctional communication (bovine: 1000 ± 148 v. 340 ± 73 unit, treated v. control; P < 0.05) and to slow meiotic progression through prophase I to metaphase II, extending the normal IVM interval (bovine: 30 v. 24 h, mouse: 22 v. 18 h; treated v. control). FSH was required to complete maturation and FSH-induced maturation was prevented by an epidermal growth factor receptor inhibitor, AG1478 (2.5 μM), demonstrating induced oocyte maturation functions via secondary autocrine signaling within the cumulus cell compartment. These effects on COC functions had profound consequences for oocyte developmental potential. In completely serum-free bovine IVP, induced-IVM more than doubled blastocyst yield (69 v. 27%, treated v. control; P < 0.05) and improved blastocyst quality (186 v. 132 blastomeres). To achieve these rates, the pre-IVM phase, the modified IVM conditions, and delayed IVF were all required. Adapting the system to the mouse, induced-IVM increased blastocyst rate (86 v. 55%, treated v. control; P < 0.05), implantation rate (51 v. 25%; P < 0.01), fetal survival rate (29 v. 5%; P < 0.01) and fetal weight (0.9 v. 0.5 g; P < 0.01). All these embryonic and fetal outcomes in mice were equivalent (P > 0.05) using induced-IVM to levels obtained from in vivo-matured control oocytes (conventional IVF). Data were analyzed by ANOVA. In conclusion, induced-IVM mimics some of the characteristics of oocyte maturation in vivo and substantially improves oocyte developmental outcomes in 2 disparate mammalian species. Adaption of this new approach to clinical/field conditions should lead to new opportunities for a wide range of reproductive biotechnologies. Such a notable increase in IVM efficiency could see IVP as the preferred embryo production technology in future livestock artificial breeding programs. Funded by an Australian Research Council Linkage Grant and Cook Australia. Thanks to M. Sasseville, M. Lane, and D. T. Armstrong.

155 Oocyte Maturation in Lyophilized In Vitro Maturation Medium as a Method to Increase the Medium’s Shelf-Life

2018 ◽  
Vol 30 (1) ◽  
pp. 217
Author(s):  
M. Rubessa ◽  
D. Weisgerber ◽  
S. Bessler ◽  
J. Bertels ◽  
B. Harley ◽  
...  
Keyword(s):  
Shelf Life ◽  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Polar Body ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Freeze Dried ◽  
Maturation Rate ◽  
The Impact

The in vitro production of bovine embryos has dramatically increased in recent years, and with it the demand of stable media with a long shelf-life. In this experiment we evaluated the impact of the freeze-dried in vitro maturation (IVM) medium (Mdry) on in vitro oocyte maturation. We compared the standard IVM and the Mdry media. Medium M199 was used as base for the IVM medium. The percentage of metaphase II oocytes and embryo production were evaluated. Media solutions (10 mL) were aliquoted into 50-mL conical tubes and lyophilized to form a powder concentrate using a Genesis freeze-dryer (VirTis, Gardener, NY, USA). Lyophilization consisted of a constant cooling from 20°C to –10°C at a constant rate of 1°C/min with a 2-h hold at –10°C before sublimation at 0°C. The Mdry medium was held at –80°C for 4 months (only serum and hormones were added before the incubation). When the IVM medium was rehydrated, the pH were adjusted to 7.4. The percentage of mature oocytes was evaluated after 24 h of maturation. The oocytes were stained with Hoechst 33342, and only oocytes with metaphase and a polar body were evaluated as matured. Abattoir-derived Holstein oocytes (n = 540) were in vitro matured (25–30/well in 400 µL) and fertilized with sexed semen, according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347-1355). The oocytes were split for analysis (432 were used for IVP and 108 for maturation rate) over 6 replicates. Twenty hours after IVF, presumptive zygotes were cultured in SOF medium at 39°C with 5% CO2, 7% O2, and 88% N2. On Day 7, embryo yields were assessed. All recorded parameters were subjected to a Student’s t-test. The parameters compared were maturation rate, cleavage rate, blastocyst rate and the percentage of embryos cleaved. The α level was set at 0.05. All data were expressed as quadratic means and mean standard deviations. The results showed no differences between the 2 groups (75.9% v. 74.1%) (t = 0.37; SD = 12.69; P = 0.36; df = 5) when we compared the nuclear maturation; however, when we evaluated embryo production, we found the Mdry treatment had a higher cleavage percentage (t = 2.39; SD = 14.81; P = 0.02; df = 5) and total embryos produced (t = 2.49; SD = 5.6; P = 0.02; df = 5) compared with the control (Table 1.). These results showed that lyophilization can be a valid method to increase the shelf life of IVP media. More replicates must be done in order to understand why the freeze-dried media produced more embryos. Table 1.Mean (SD in parentheses) percentage cleavage and blastocysts

Gene transcription and regulation of oocyte maturation

2004 ◽  
Vol 16 (2) ◽  
pp. 55 ◽  
Author(s):  
Karina F. Rodriguez ◽  
Charlotte E. Farin
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Transcriptional Control ◽  
Molecular Mechanisms ◽  
Developmental Competence ◽  
Developmental Potential ◽  
Oocyte Developmental Competence ◽  
Specific Factors

The developmental potential of an embryo is dependent on the developmental potential of the oocyte from which it originates. The process of oocyte maturation is critical for the efficient application of biotechnologies such as in vitro embryo production and mammalian cloning. However, the overall efficiency of in vitro maturation remains low because oocytes matured in vitro have a lower developmental competence than oocytes matured in vivo. Furthermore, oocytes that have been exposed to gonadotropins have greater developmental competence than oocytes matured in the absence of gonadotropins. By understanding the molecular mechanisms underlying gonadotropin-induced maturation, improvement in oocyte maturation technologies may be expected as procedures to manipulate specific factors involved in signalling for resumption of meiosis are identified. The present review will focus on transcriptional mechanisms underlying the maturation of mammalian oocytes in vitro, as well as on the acquisition of oocyte developmental competence. In addition, a working model for the transcriptional control of mammalian oocyte maturation is proposed.

339 OXYGEN CONCENTRATION DURING IN VITRO MATURATION OF MURINE OOCYTES INFLUENCES SUBSEQUENT FETAL AND PLACENTAL OUTCOMES

2007 ◽  
Vol 19 (1) ◽  
pp. 285
Author(s):  
K. M. Banwell ◽  
M. Lane ◽  
D. L. Russell ◽  
K. L. Kind ◽  
J. G. Thompson
Keyword(s):  
Oxygen Concentration ◽  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Weight Ratio ◽  
Average Weight ◽  
Intermediate Cell ◽  
Blastocyst Development ◽  
Oxygen Environment

Although the oxygen environment of the ovarian follicle is thought to influence oocyte developmental competence, little is known of the optimal oxygen environment for oocyte in vitro maturation (IVM). Previously, we found that oxygen concentration (either 2, 5, 10, or 20% O2; 6% CO2; and balance of N2) during IVM of murine oocytes had no effect on maturation rate or subsequent fertilization, cleavage, and blastocyst development rates. However, 2% O2 results in blastocysts with a higher (P &lt; 0.05) trophectoderm cell number (mean � SEM, 35.1 � 2.3) when compared to 20% (19.4 � 1.7), with 5 and 10% O2 yielding similar but intermediate cell numbers. When examined for cell apoptosis by TUNEL labelling, the 2% O2 IVM-derived embryos were also found to have a significantly higher percentage of cells undergoing apoptosis compared to the 5% O2 IVM-derived embryos and embryos derived from in vivo matured oocytes (unpublished data). Although the blastocyst development rate is not affected by varying oxygen environment during oocyte maturation, the resultant blastocysts exhibited signs of differing quality. The aim of this study was to investigate the effect of varying oxygen during IVM on post-transfer outcomes. Immature cumulus-oocyte complexes (COCs) were collected from the ovaries of eCG-stimulated CBAB6F1 females (21 days) and cultured for 17–18 h under 2, 5, or 20% O2, whereas in vivo-matured COCs were also collected post-hCG. After IVF/C (both under 5% O2), 6 blastocysts were transferred to each uterine horn of pseudopregnant Swiss recipients. Fetal and placental parameters were measured on Day 18 of pregnancy. The ability of the embryos to implant or develop was not altered by IVM oxygen concentration. However, the average weight of fetuses derived from 5% O2 matured oocytes was reduced (823.3 � 28.1 mg, P &lt; 0.05) compared to those in the 20% O2 group (928.5 � 26.1 mg). The average weight of the placenta in the 5% O2 group was also reduced (87.4 � 4.0 mg) compared to those derived from in vivo-matured oocytes (104.5 � 5.4 mg). In contrast, the fetal:placental weight ratio was unchanged in the 5% O2 treatment, suggesting these placentae, although small, are still efficient. This is the first evidence that programming of fetal/placental growth occurs from treatments applied during oocyte maturation.

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