220 EFFECT OF ZINC SUPPLEMENTATION DURING IN VITRO MATURATION ON EQUINE BLASTOCYST RATES AFTER INTRACYTOPLASMIC SPERM INJECTION

2016 ◽  
Vol 28 (2) ◽  
pp. 241
Author(s):  
Y. H. Choi ◽  
J. R. Gibbons ◽  
H. S. Canesin ◽  
K. Hinrichs
Keyword(s):  
Oocyte Maturation ◽  
Follicular Fluid ◽  
Intracytoplasmic Sperm Injection ◽  
In Vitro Maturation ◽  
Zinc Supplementation ◽  
Blastocyst Formation ◽  
Blastocyst Development ◽  
Zinc Concentrations ◽  
The Mean

Use of intracytoplasmic sperm injection (ICSI) in horses has growing clinical and research importance; however, little is known of factors affecting efficacy of this system. Supplementation of zinc during in vitro maturation (IVM) has been shown to increase oocyte glutathione levels, decrease reactive oxygen species, and increase blastocyst rates in vitro in cattle and pigs, but has not been evaluated in the horse. In this study, we examined the effect of zinc supplementation during IVM on rates of maturation and blastocyst formation after ICSI. Oocytes were collected from follicles ≥5 mm in diameter in live mares. Blood serum and follicular fluid from 15- to 30-mm follicles were collected from 3 mares for zinc analysis by flame atomic absorption spectrometry. Oocytes were held overnight at room temperature (Choi et al. 2006 Theriogenology 66, 955–963), and then randomly assigned to IVM in the presence of 1 of 4 concentrations of added zinc (0.0, 0.5, 1.0, and 1.5 μg mL–1), added as ZnSO4·7H2O. The oocytes were cultured for IVM in M199 with Earle’s salts, 5 mU mL–1 FSH, and 10% fetal bovine serum (FBS) for 30 h. The oocytes were then denuded of cumulus and those with a polar body subjected to ICSI with frozen-thawed sperm. Presumptive zygotes were cultured in a commercial human embryo culture medium (LifeGlobal; http://www.lifeglobalgroup.com/), supplemented with 10% FBS, under 6% CO2, 5% O2, and 89% N2 at 38.2°C. On Day 5 (Day 0 = injection day), embryos were evaluated for presumptive cleavage and transferred to medium with 20 mM added glucose. Blastocyst formation was evaluated on Days 7 to 11. Data were analysed by Fisher’s exact test. The mean zinc concentrations in mare serum and follicular fluid were 0.50 and 0.44 μg mL–1, respectively. The mean zinc concentration of the FBS was 2.70 μg mL–1, and that of IVM medium containing 10% FBS were 0.28, 0.80, 1.23, and 1.68 μg mL–1 for the 0.0, 0.5, 1.0, and 1.5 μg mL–1 added-zinc treatments, respectively. The rates of oocyte maturation were not significantly different among treatments (43/61, 70%; 46/70, 66%; 45/71, 63%; and 49/70, 70%, respectively). Neither cleavage rates (81–92%) nor blastocyst rates (12/42, 29%; 9/43, 21%, 8/44, 18%, and 15/48, 31%, respectively) differed significantly among treatments. However, the proportion of blastocysts that developed on Day 7 out of total blastocysts was higher for the combined added-zinc treatments (0.5, 1, and 1.5 μg mL–1) than for the treatment with no added zinc (15/32, 47% v. 1/12, 8%, respectively; P < 0.05). These results indicate that supplementation of zinc to the IVM medium used did not influence equine oocyte maturation or blastocyst development rates but may have improved embryo quality, as reflected in earlier blastocyst development. The more subtle response seen, compared with that reported in other species, may be because the 10% FBS resulted in zinc concentrations in the basal medium (0.28 μg mL–1) only slightly lower than that in equine follicular fluid (0.44 μg mL–1). This work was supported by the Link Equine Research Endowment Fund, Texas A&M University, and by the Clinical Equine ICSI Program, Texas A&M University.

300 BLASTOCYST PRODUCTION BY IN VITRO MATURATION AND DEVELOPMENT OF PORCINE OOCYTES IN DEFINED MEDIA FOLLOWING INTRACYTOPLASMIC SPERM INJECTION

2007 ◽  
Vol 19 (1) ◽  
pp. 265
Author(s):  
Y. Kobayashi ◽  
M. Fukui
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
In Vitro Maturation ◽  
Subsequent Development ◽  
Basic Medium ◽  
Control Medium ◽  
Blastocyst Formation ◽  
Cell Numbers ◽  
Defined Media ◽  
The Mean

Most culture media for in vitro production (IVP) of porcine embryos contain serum or bovine serum albumin (BSA); especially in the case of in vitro maturation (IVM) porcine follicular fluid is added. The present study was carried out to establish porcine-defined IVP. In Experiment 1, we investigated the efficacy of additional 0.6 mM cystine, 100 �M cysteamine (Cys), or cystine + Cys to a defined TCM-199 maturation medium with regard to the developmental competence of in vitro-matured porcine oocytes following intracytoplasmic sperm injection (ICSI). The control medium was a modified TCM-199 containing 0.05% (w/v) polyvinyl alcohol (PVA). In Experiment 2, the effect of epidermal growth factor (EGF) addition to a modified porcine zygote medium (mPZM) for in vitro culture (IVC) medium was investigated on embryonic development following ICSI. As positive and negative controls, 0.3% BSA (mPZM-3) or 0.3% PVA (mPZM-4), respectively, was added to the basic medium. Five or 10 ng mL-1 of EGF was supplemented in the negative control medium (mPZM-4). All percentage data on cleavage and blastocyst development were subjected to arcsine transformation before statistical analysis using the STATVIEW program (Abacus Concepts, Berkeley, CA). The mean cell numbers per blastocyst (assessed by Giemsa staining method) were analyzed by one-way ANOVA, and the differences among the groups were also analyzed using Tukey-Kramer multiple comparison tests. In Experiment 1, there were no significant differences in the rates of cleavage (31.4 to 64.3%) and blastocyst formation (6.5 to 22.9%) among the treatment and control groups. The mean cell numbers per blastocyst ranged from 30 to 48 among the groups, without significant differences. In Experiment 2, the rates of cleavage (43.0 to 58.0%) and blastocyst formation (14.0 to 23.6%), and the mean cell numbers per blastocyst (30 to 37) were not significantly different among the groups. However, the addition of 5 ng mL-1 of EGF to the mPZM-4 resulted in a significantly (P d 0.05) higher blastocyst rate (48.6%) to cleaved embryos than the other two defined groups (mPZM-4 and mPZM-4 with 10 ng mL-1 EGF: 23.4% and 23.1%, respectively), but not significantly different with mPZN-3 (40.1%). The present results indicate that TCM-199 with added cysteamine (100 �M) can be used as a defined IVM medium for porcine oocytes, and further addition of cystine into the IVM medium is not necessary. The addition of 5 ng mL-1 of EGF to a defined IVC medium enhanced subsequent development after ICSI. These results show that porcine blastocysts can be produced by defined media throughout the steps of IVP (IVM, ICSI, and IVC). This study was partly supported by a grant-in-aid for Scientific Research (17580242) from the Japan Society for the Promotion of Science.

scholarly journals 311EFFECT OF OOCYTE MATURATION MEDIA ON THE SPEED OF MEIOTIC PROGRESSION AND BLASTOCYST DEVELOPMENT OF BOVINE EMBRYOS

2004 ◽  
Vol 16 (2) ◽  
pp. 275
Author(s):  
D. Fischer ◽  
J. Bordignon ◽  
C. Robert ◽  
D. Betts
Keyword(s):  
Embryo Development ◽  
Oocyte Maturation ◽  
Immunofluorescence Microscopy ◽  
Chromosomal Abnormalities ◽  
Culture Media ◽  
Blastocyst Formation ◽  
Blastocyst Development ◽  
Nuclear Maturation ◽  
Meiotic Progression

Environment is crucial for in vitro development of gametes and embryos. The recent progression of culture media towards defined conditions brought to surface the impact of different medium supplements on oocyte and embryo development. In this work we evaluate the effect of various oocyte culture media on bovine oocyte maturation and subsequent embryo development. Bovine cumulus-oocyte complexes were recovered from slaughterhouse ovaries and matured in vitro in either TCM-199 (Gibco) or SOF (Synthetic Oviduct Fluid) media supplemented with BSA (fatty acid-free) or serum (fetal bovine serum). Oocytes from each treatment group were denuded and fixed at 18, 20, 22, 24, 26 and 28h post-maturation (p.m.). Oocyte meiotic progression was monitored in each of the groups (n=28–40 oocytes/group) by immunofluorescence microscopy of chromatin. Oocytes matured in SOF showed a slower rate of meiotic progression when compared to the other groups, with the highest percentage of oocytes reaching the MII stage by 28h p.m. (60.71% SOF-BSA, 71.43% SOF-Serum). The fastest developmental rate was observed in oocytes matured in TCM-serum (77.15% at 24h p.m.) followed by oocytes matured in TCM-BSA (74.29% at 26h p.m.). In order to evaluate the effect of nuclear maturation on chromosome segregation, chromosomal organization of MII oocytes was evaluated by immunofluorescence microscopy within each media group (n=26–31 oocytes/group) at 18, 22 and 26h p.m.. No chromosomal abnormalities were found at 18h p.m.. Both media supplemented with BSA induced lower frequencies of chromosomal abnormalities (0 to 3.23%) and (3.57 to 7.69%) for SOF and TCM, respectively, when compared to their serum-supplemented counterparts (7.14 to 11.54%) and (10 to 10.71%) for SOF and TCM, respectively at 22 and 26h p.m.. Remarkably, the maturation medium and its supplements influenced the speed of blastocyst development. For this experiment, oocytes were matured in TCM-BSA, TCM-Serum, SOF-BSA or SOF-serum, fertilized in vitro in a TALP-base media supplemented with BSA and cultured in SOF-BSA. Blastocyst development was assessed at 7, 8 and 9 days of culture. Cleavage rates were similar between the groups (84–90%), whereas development rates to blastocyst stage varied among treatment groups. Maturation in SOF-BSA induced a delay in blastocyst formation that reached its highest percentage only on day 9 of culture (30.8%); moreover, blastocyst development was carried over until Day 12. When oocytes were matured in the presence of serum, the number of blastocysts did not increase after Day 8 of culture (26.6%, TCM-serum). These results provide evidence of a severe impact of oocyte culture media on the nuclear maturation of oocytes and their subsequent embryonic development after IVF. Moreover, the difference in the rate of oocyte maturation and blastocyst formation emphasizes the necessity for reviewing and adapting current protocols to new systems such as SOF-BSA. [Research funded by NSERC and OMAF of Canada.]

188 HUMAN FOLLICULAR FLUID IN EQUINE IN VITRO MATURATION MEDIUM SUPPORTS IN VITRO MATURATION AND VIABLE INTRACYTOPLASMIC SPERM INJECTION-BLASTOCYST PREGNANCIES

2012 ◽  
Vol 24 (1) ◽  
pp. 206
Author(s):  
C. Makloski ◽  
R. Gotti ◽  
K. Harris ◽  
J. Bottger ◽  
M. Meintjes
Keyword(s):  
Follicular Fluid ◽  
Intracytoplasmic Sperm Injection ◽  
In Vitro Maturation ◽  
Transvaginal Ultrasound ◽  
Human Follicular Fluid ◽  
Immature Oocytes ◽  
Treatment Groups ◽  
Maturation Medium ◽  
And Control

The aim of this study was 2-fold: (1) To determine if altrenogest-treated mares will yield higher numbers of quality in vitro-matured (IVM) oocytes than early pregnant mares and cycling/control mares and (2) if the addition of human follicular fluid (HFF) to IVM medium can support IVM and viable pregnancies from in vitro-produced blastocysts. In this study, 18 mares were assigned to 3 equally sized treatment groups and each mare was subjected to follicle aspiration every 10 to 11 days without monitoring follicular growth. The 3 treatment groups were altrenogest-treated mares (0.044 mg kg–1 of PO daily), early pregnant mares (30–110 days) and control/cycling mares. Using transvaginal ultrasound guidance, all visible follicles were aspirated. Altrenogest-treated mares each yielded more follicles (8.75) per aspiration session when compared with the control mare group (5.75) and the pregnant mare group (3.72), but there was no difference in oocyte recovery rates among the groups (Table 1). A limited number of these oocytes were subjected to in vitro maturation. After heated (38.5°C) transport of oocytes to an off-site laboratory, the oocytes were placed in maturation medium containing 10% HFF obtained from preovulatory follicles after ovulation induction, 20% serum substitute supplement and no hormones for 36 h. This approach yielded a maturation rate of 61.8, 68.8 and 82.0% for the altrenogest, pregnant and control treatment groups, respectively (not significant). Mature oocytes (n = 65) were injected with frozen-thawed sperm using a standard intracytoplasmic sperm injection (ICSI) technique. Four expanding blastocysts (Table 1) were selectively transported back to the embryo transfer facility and transcervically transferred into recipient mares on Day 6 post-ICSI. These 4 transfers resulted in 2 viable, normally progressing pregnancies, ongoing beyond 60 days of gestation. Both pregnancies resulted from the altrenogest-treated aspiration group. In this study we concluded that (1) altrenogest-treated mares provide more follicles and may be a better source of viable immature oocytes for the production of ICSI embryos and foals, but their overall advantage is unclear; (2) addition of HFF to IVM media, in the absence of added gonadotropins, can support oocyte maturation, blastocyst production and viable pregnancies; (3) an aspiration schedule of every 10 to 11 days without ultrasonic monitoring can yield viable immature oocytes, capable of producing ICSI blastocysts, resulting in viable pregnancies. Table 1.Altrenogest-treated mares compared to early pregnant mares and control mares

228 EFFECT OF INSULIN ON BOVINE OOCYTE MATURATION, CUMULUS CELL APOPTOSIS, AND EARLY EMBRYO DEVELOPMENT IN VITRO

2015 ◽  
Vol 27 (1) ◽  
pp. 203
Author(s):  
I. Lindgren ◽  
P. Humblot ◽  
D. Laskowski ◽  
Y. Sjunnesson
Keyword(s):  
Embryo Development ◽  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Insulin Treatment ◽  
Cumulus Cells ◽  
Early Embryo ◽  
Blastocyst Formation ◽  
Early Embryo Development ◽  
Maturation In Vitro

Dairy cow fertility has decreased during the last decades, and much evidence indicates that metabolic disorders are an important part of this decline. Insulin is a key factor in the metabolic challenge during the transition period that coincides with the oocyte maturation and may therefore have an impact on the early embryo development. The aim of this study was to test the effect of insulin during oocyte maturation on early embryo development by adding insulin during the oocyte maturation in vitro. In this study, abattoir-derived bovine ovaries were used and cumulus-oocyte complexes (n = 991) were in vitro matured for 22 h according to standard protocols. Insulin was added during maturation in vitro as follows: H (10 µg mL–1 of insulin), L (0.1 µg mL–1 of insulin), or Z (0 µg mL–1 of insulin). After maturation, oocytes were removed and fixed in paraformaldehyde before staining. Click-it TUNEL assay (Invitrogen, Stockholm, Sweden) was used for apoptotic staining and DRAQ5 (BioNordika, Stockholm, Sweden) for nuclear staining (n = 132). Cumulus-oocyte complexes were evaluated using laser scanning confocal microscope (Zeiss LSM 510, Zeiss, Oberkochen, Germany). Five levels of scans were used to assess oocyte maturation (MII stage) and apoptosis. Because of incomplete penetration of the TUNEL stain (3–5 layers of cumulus cells), only the outer 2 layers of the cumulus complex were investigated regarding apoptosis. Apoptotic index was calculated as apoptotic cells/total cells visualised. Remaining oocytes were fertilized and cultured in vitro until Day 8. Day 7 and Day 8 blastocyst formation was assessed as well as blastocyst stage and grade. Effect of insulin treatment on variables was analysed by ANOVA following arc sin √p transformation. Post-ANOVA comparisons between H+L group v. Z were performed by using the contrast option under GLM (Scheffé test). Results are presented as least squares means ± s.e. P-values ≤ 0.05 were considered as statistically significant. Insulin treatment during oocyte maturation in vitro had no significant effect on oocyte nuclear maturation or apoptotic index of the cumulus cells (Z: 0.052 ± 0.025, L: 0.039 ± 0.016, H: 0.077 ± 0.044, P > 0.05). No effect was seen on cleavage rates (Z: 0.85 ± 0.02, L: 0.85 ± 0.02, H: 0.89 ± 0.03, P > 0.05), but insulin treatment significantly decreased Day 7 rates from fertilized oocytes (Z: 0.19 ± 0.02, L: 0.14 ± 0.02, H: 0.12 ± 0.02, P < 0.05). This study also showed a significantly retarded developmental stage and decreased grade of blastocysts in insulin-treated groups taken together when compared with the control group (P < 0.05). In this study, no effect of insulin supplementation during in vitro maturation was seen on bovine oocyte maturation and apoptosis of cumulus cells, but blastocyst formation and development were negatively affected. Further studies are needed for understanding the relationship between the addition of insulin during maturation in vitro and impaired blastocyst formation. Insulin is a common supplement in the first phase of the first in vitro maturation medium for pig oocytes and is believed to have a beneficial effect on this species.Funding was received from Stiftelsen Nils Lagerlöfs Fond H12–0051-NLA.

167 DEVELOPMENTAL COMPETENCE OF PORCINE OOCYTES DERIVED FROM SMALL- OR MEDIUM-SIZED FOLLICLES AND DENUDED OF CUMULUS CELLS BEFORE AND DURING IN VITRO MATURATION

2017 ◽  
Vol 29 (1) ◽  
pp. 192
Author(s):  
P. Ferré ◽  
K. X. Nguyen ◽  
T. Wakai ◽  
H. Funahashi
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Polar Body ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cumulus Cells ◽  
Developmental Competence ◽  
Blastocyst Formation ◽  
First Polar Body

This experiment was undertaken to assess the meiotic and developmental competences of oocytes derived from different sized follicles and denuded of cumulus cells 0, 20, and 44 h after the start of culture for in vitro maturation (IVM). Groups of 60 oocyte-cumulus complexes from small- (SF; <3 mm) and medium-sized follicles (MF; 3–6 mm) were cultured for IVM in porcine oocyte medium with 50 μM β-mercaptoethanol supplemented with 1 mM dibutyryl-cyclic adenosine monophosphate, 10 IU mL−1 of eCG, and 10 IU mL−1 of hCG for 20 h at 39°C and 5% CO2 in air. Then, after washing, they continued culture in fresh β-mercaptoethanol without dibutyryl-cyclic adenosine monophosphate and gonadotropins under the same conditions for another 24 h. At 0, 20, and 44 h of IVM, cumulus cells were removed with 0.1% (wt/vol) hyaluronidase and the denuded oocytes continued IVM culture following the protocol. Mature oocytes with the first polar body were selected, parthenogenetically activated with a single electrical pulse (DC: 1.2 kV/cm, 30 µs), incubated with 4% (wt/vol) BSA and 5 μM cytochalasin B for 4 h, and cultured in porcine zygote medium for 5 days. Cleavage and blastocyst formation rates were observed on Day 2 and 5, respectively. Blastocysts were stained with 4’,6-diamidino-2-phenylindole for cell count assessment. The experiment was replicated 5 times and analysed with a 1- or 2-way ANOVA. If P < 0.05 in ANOVA, a Tukey multiple comparisons test was performed. Regardless of the time of cumulus cell removal, oocytes from MF had significantly higher in rates of maturation, cleavage, and blastocyst rates, as compared with those from SF, whereas there were no significant differences in the cell number of blastocysts between SF and MF (32 v. 34 cells, respectively). When oocytes were denuded before IVM culture, rates of oocyte maturation (37.6% in SF and 50.8% in MF), and blastocyst formation (2.7% in SF and 27.3% in MF) were significantly lower than controls (51.2% in SF and 76% in MF; 25.8% in SF and 48.5% in MF, respectively). When oocytes were denuded 20 h after the start of IVM, oocyte maturation rates were significantly increased (64.1% in SF and 82.5% in MF) as compared with controls, whereas no significant differences were observed in cleavage and blastocyst formation rates in comparison with controls. These results conclude that removing cumulus cells from oocyte-cumulus complexes 20 h after the start of IVM improves the meiotic competence of oocytes derived from both SF and MF, without any reduction of developmental competence of the oocytes following parthenogenetical activation.

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.

191 SUPPLEMENTATION OF MATURATION MEDIUM WITH FOLLICULAR FLUID, EPIDERMAL GROWTH FACTOR AND NEUREGULIN AFFECTS MITOCHONDRIAL DNA REPLICATION, OOCYTE MATURATION AND EMBRYO DEVELOPMENT IN PIGS

2012 ◽  
Vol 24 (1) ◽  
pp. 208
Author(s):  
J. Mao ◽  
K. M. Whitworth ◽  
L. D. Spate ◽  
E. M. Walters ◽  
J. Zhao ◽  
...  
Keyword(s):  
Growth Factor ◽  
Embryo Development ◽  
Oocyte Maturation ◽  
Follicular Fluid ◽  
Copy Number ◽  
In Vitro Maturation ◽  
Meiotic Maturation ◽  
Mtdna Copy Number ◽  
Maturation Medium

Mitochondria supply the majority of ATP in a cell. Mitochondrial DNA (mtDNA) copy number in oocytes might be used as a marker of viability and might be a key determinant of pre-implantation embryo development. However, little is known about mtDNA copy number changes during porcine oocyte maturation and its regulation by extracellular growth factors. The objectives of the current study were to determine the effects of supplementation of in vitro maturation medium with porcine follicular fluid (pFF; 0, 10, 20 and 30%), epidermal growth factor (EGF; 10 ng mL–1), neuregulin 1 (NRG; 20 ng mL–1) and NRG + IGF1 (insulin-like growth factor-1; 100 ng mL–1 + NRG, 20 ng mL–1) during in vitro maturation on mtDNA copy number, oocyte meiotic maturation and subsequent embryo development after parthenogenic activation. Follicular fluid used for the pFF supplementation experiment was prepared from medium-sized (3–6 mm in diameter) healthy follicles. Cumulus–oocyte complexes (COCs) were collected from antral follicles (3–6 mm in diameter), cultured in LH- and FSH-containing maturation medium for 22 h at 38.5°C, transferred into basic maturation medium without FSH and LH and cultured for another 22 h. The basic maturation medium was TCM-199 supplemented with 0.1% polyvinylalcohol (w/v), 3.05 mM D-glucose, 0.91 mM sodium pyruvate, 10 μg mL–1 of gentamicin, 0.57 mM cysteine and without or with different growth factors depending on the experimental design. In total, 177 germinal vesicle (GV) oocytes and 3837 MII oocytes were used for this study. All data were analyzed by the general linear model (GLM) procedure of SAS software (V9.2). The mtDNA copy number in oocytes increased (P < 0.05) from GV to MII stage oocytes (MII oocytes from all treatment groups pooled). Supplementation of IVM media with 10% pFF decreased mtDNA copy number (P < 0.05), whereas 20 and 30% pFF had no major effect on mtDNA copy number, resulting in a quadratic correlation between percentage of pFF and mtDNA copy number. There was a negative linear correlation between percentage of pFF and oocyte meiotic maturation, with a higher percentage of pFF inhibiting meiotic maturation (73.2 ± 5.2, 71.9 ± 4.8, 64.1 ± 8.5 and 65.8 ± 6.4% for 0, 10, 20 and 30% pFF groups, respectively). The mtDNA copy numbers in EGF and NRG-treated MII oocytes were significantly higher than those in GV oocytes, whereas the control was not different (EGF, 237 042.6 ± 22 198.2; NRG, 281 293.4 ± 22 893.5; and control, 231 856.8 ± 21 883.5 in MII oocytes vs 192 288.7 ± 21 675.4 in GV oocytes). The EGF, NRG and NRG+IGF1 treatments enhanced oocyte maturation as well. There was no difference in Day-7 blastocyst formation between EGF, NRG+IGF1 and the control, whereas the NRG treatment enhanced blastocyst formation as compared to the control (23.8 ± 2.4 vs 15.1 ± 2.1%; P < 0.05). This study demonstrated that there was an increase in mtDNA copy number during in vitro maturation. The EGF and NRG treatments stimulated mitochondria biogenesis, which may provide new means to increase oocyte quality and enhance embryonic development.

scholarly journals Exposure to follicular fluid during oocyte maturation and oviductal fluid during post-maturation does not improve in vitro embryo production in the horse

Zygote ◽  
2017 ◽  
Vol 25 (5) ◽  
pp. 612-630 ◽  
Author(s):  
Cécile Douet ◽  
Olivia Parodi ◽  
Nicola Antonio Martino ◽  
Giovanni Michele Lacalandra ◽  
Michele Nicassio ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Follicular Fluid ◽  
Culture Conditions ◽  
Blastocyst Development ◽  
Embryo Production ◽  
Development Rates ◽  
Maturation Medium ◽  
In Vitro Embryo Production ◽  
Oviductal Fluid

SummaryMost wild equids and many domestic horse breeds are at risk of extinction, so there is an urgent need for genome resource banking. Embryos cryopreservation allows the preservation of genetics from male and female and is the fastest method to restore a breed. In the equine, embryo production in vitro would allow the production of several embryos per cycle. Intracytoplasmic sperm injection (ICSI) is used to generate horse embryos, but it requires expensive equipment and expertise in micromanipulation, and blastocyst development rates remain low. No conventional in vitro fertilization (IVF) technique for equine embryo production is available. The development of culture conditions able to mimic the maturation of the oocyte in preovulatory follicular fluid (pFF) and the post-maturation in oviductal fluid (OF) may improve embryo production in vitro. Our aim was to analyse the effect of in vitro maturation in pFF and incubation in OF on in vitro maturation of equine oocytes, fertilization using conventional IVF or ICSI, and embryo development after culture in synthetic oviductal fluid (SOF) or DMEM-F12. Oocytes collected from slaughtered mares or by ovum pick up were matured in vitro in pFF or semi-synthetic maturation medium (MM). The in vitro maturation, fertilization and development rates were not statistically different between pFF and MM. After in vitro maturation, oocytes were incubated with or without OF. Post-maturation in OF did not significantly improve the fertilization and development rates. Thus, in our study, exposure to physiological fluids for oocyte maturation and post-maturation does not improve in vitro embryo production in the horse.

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