The effect of vitrification of immature bovine oocytes to the subsequent in vitro development and gene expression

SummaryImmature bovine oocytes were vitrified using the cryotop method and their post-warming survivability and capability to undergo in vitro maturation, fertilization and subsequent embryonic development were evaluated. In addition throughout the embryonic 2-cell, 4-cell, morula and blastocyst stages, the expression of four developmentally important genes (Cx43, CDH1, DNMT1 and HSPA14) was analysed using the real-time polymerase chain reaction (PCR). Immature oocytes (n = 550) were randomly assigned to non-vitrified (fresh) or cryotop vitrification groups using ethylene glycol (EG) with 1,2 propanediol (PROH) or dimethylsulphoxide (DMSO). After warming, oocytes survivability, embryo cleavage and embryonic developmental rates were not statistically different between the two cryoprotectants groups. However, the DMSO group had a lower (P < 0.05) oocyte maturation rate compared with the fresh and PROH groups. For morula and blastocyst rates, the DMSO group achieved a lower (P < 0.05) morula rate compared with the fresh group, while at the blastocyst stage, there were no differences between fresh and both cryoprotectants groups. For molecular analysis, at the 4-cell stage, most studied genes showed an inconsistent pattern of expression either from the PROH or DMSO groups. Noteworthily, these differences were limited at the morula and blastocyst stages. In conclusion, the cryotop method is sufficient for vitrification of immature bovine oocytes, both for embryonic developmental competence and at the molecular level. Moreover, PROH showed some advantage over DMSO as a cryoprotectant.

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198 THE EFFECT OF SOURCE AND IN VITRO MATURATION ON THE ABUNDANCE OF MATERNAL mRNA OF SELECTED GENES IN FOLLICULAR BOVINE OOCYTES AND THEIR INFLUENCE ON IN VITRO DEVELOPMENT

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab198 ◽

2011 ◽

Vol 23 (1) ◽

pp. 199

Author(s):

T. Somfai ◽

K. Imai ◽

M. Kaneda ◽

S. Akagi ◽

S. Haraguchi ◽

...

Keyword(s):

Gene Expression ◽

Embryo Development ◽

In Vitro Maturation ◽

Blastocyst Stage ◽

Cell Stage ◽

In Vitro Development ◽

Before And After ◽

Vitro Development ◽

Bovine Oocytes

The aim of the present study was to investigate the effect of oocyte source and in vitro maturation (IVM) on the expression of selected genes in bovine oocytes and their contribution to in vitro embryo development. Follicular oocytes were collected either by ovum pick-up from live cows or by the aspiration of ovaries of slaughtered cows following storage in Dulbecco’s PBS at 15°C for overnight. In vitro maturation was performed according to the method of (Imai et al. 2006 J. Reprod. Dev. 52, 19–29 suppl.). Gene expression was assessed before and after IVM by real-time PCR. The following genes were investigated: GAPDH, G6PDH, ACTB, H2A, CCNB1, MnSOD, OCT4, SOX2, CX43, HSP70, GLUT8, PAP, GDF9, COX1, ATP1A1, CDH1, CTNNB1, AQP3, DYNLL1, DYNC 1/1, and PMSB1. In brief, mRNA was extracted from 20 oocytes per sample using a Qiagen RNeasy Micro Kit (Qiagen, Valencia, CA). Gene expression was analysed by a Roche Light Cycler 480 device and software (Roche, Indianapolis, IN). Relative expression of each gene was normalized to CCNB1, which in preliminary experiments appeared the most stably expressed irrespective of oocyte source and meiotic stage. Three replications were performed. Data were analysed by paired t-test. In immature ovum pick-up oocytes, genes related to metabolism (GAPDH, G6PDH, GLUT8) and stress (MnSOD, HSP70), and also OCT4, ATP1A1, and DYNC1/1 showed significantly (P < 0.05) higher expression compared with immature oocytes collected from slaughtered-stored ovaries. The expression of GDF9, GLUT8, CTNNB1, and PMSB1 was significantly (P < 0.05) reduced during IVM irrespective of the oocyte source. In a second experiment, IVF IVM oocytes showing an early (at 22 to 25 h after IVF) or late (at 27 to 30 h after IVF) first cleavage were either cultured in vitro or analysed for gene expression at the 2-cell stage. A higher (P < 0.05) rate of early-cleaving oocytes developed to the blastocyst stage compared with the rate of late-cleaving ones (46.2% v. 15.6%, respectively). Nevertheless, only ATP1A1 showed significantly reduced (P < 0.05) expression in late-cleaving embryos compared with early-cleaving ones. Our results suggest that although removal and storage of ovaries and IVM caused a reduction in the relative abundance of several genes in oocytes, in most cases, this did not affect embryo development. Among the genes studied, only ATP1A1 was correlated with in vitro development.

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N-acetyl-L-cysteine Improves the Developmental Competence of Bovine Oocytes and Embryos Cultured In Vitro by Attenuating Oxidative Damage and Apoptosis

Antioxidants ◽

10.3390/antiox10060860 ◽

2021 ◽

Vol 10 (6) ◽

pp. 860

Author(s):

Wu-Sheng Sun ◽

Hoon Jang ◽

Mi-Ryung Park ◽

Keon Bong Oh ◽

Haesun Lee ◽

...

Keyword(s):

Embryonic Development ◽

Early Stage ◽

Developmental Competence ◽

Beneficial Effects ◽

Developmental Rates ◽

A Cell ◽

Bovine Oocytes ◽

Dose Dependent

Oxidative stress has been suggested to negatively affect oocyte and embryo quality and developmental competence, resulting in failure to reach full term. In this study, we investigated the effect of N-acetyl-L-cysteine (NAC), a cell-permeating antioxidant, on developmental competence and the quality of oocytes and embryos upon supplementation (0.1–10 mM) in maturation and culture medium in vitro using slaughterhouse-derived oocytes and embryos. The results show that treating oocytes with 1.0 mM NAC for 8 h during in vitro maturation attenuated the intracellular reactive oxygen species (ROS) (p < 0.05) and upregulated intracellular glutathione levels (p < 0.01) in oocytes. Interestingly, we found that NAC affects early embryonic development, not only in a dose-dependent, but also in a stage-specific, manner. Significantly (p < 0.05) decreased cleavage rates (90.25% vs. 81.46%) were observed during the early stage (days 0–2), while significantly (p < 0.05) increased developmental rates (38.20% vs. 44.46%) were observed during the later stage (from day 3) of embryonic development. In particular, NAC supplementation decreased the proportion of apoptotic blastomeres significantly (p < 0.05), resulting in enhanced hatching capability and developmental rates during the in vitro culture of embryos. Taken together, our results suggest that NAC supplementation has beneficial effects on bovine oocytes and embryos through the prevention of apoptosis and the elimination of oxygen free radicals during maturation and culture in vitro.

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346 BOVINE EMBRYO DEVELOPMENT AFTER IVM/IVF/IVC OF OOCYTES STORED FOR 22 H IN VARIOUS MEDIA

Reproduction Fertility and Development ◽

10.1071/rdv19n1ab346 ◽

2007 ◽

Vol 19 (1) ◽

pp. 288

Author(s):

C. Kubota ◽

T. Kojima ◽

T. Nagai ◽

X. Tian ◽

X. Yang

Keyword(s):

Subsequent Development ◽

Industrial Applications ◽

Blastocyst Stage ◽

Developmental Competence ◽

Control Group ◽

Bovine Embryo ◽

Becton Dickinson ◽

In Vitro Storage ◽

Bovine Oocytes

The timing of IVM–IVF–IVC is restricted by the onset of oocyte maturation, and sometimes oocytes must be treated at midnight. If we could regulate the timing of IVM of oocytes without decreasing their developmental competence, the IVM–IVF–IVC system could be a more applied technology. The present study was performed to examine the effects of in vitro storage of bovine oocytes in simple media prior to maturation culture to manipulate the start of IVM. Bovine follicular fluid (bFF), Dulbecco's PBS (PBS), M199 Earle salts (M199), and Earle salts supplemented with 5 mM NaHCO3 (M199A) were used as the fundamental media, after an addition of antibiotics, for in vitro storage of bovine cumulus–oocyte complexes (COCs) collected from ovaries obtained at the slaughterhouse. The fundamental media except for bFF were supplemented with 10&percnt; fetal bovine serum (FBS) or 1 mg mL−1 polyvinyl alcohol (PVA). COCs were collected from follicles (3–8 mm in diameter) and washed twice in each medium; then approximately 50 COCs were submerged in 1 mL of each medium in cryotubes (Falcon #2812, 2.5 mL; Becton Dickinson Labware, Lincoln, NJ, USA), which were stored in a container kept at 38.5°C for 22 h under air-closed condition (in vitro storage: IVS). Subsequently, the stored COCs were in vitro-matured (IVM) for 22 h in M199 with 10&percnt; FBS and 20 µg mL−1 estradiol, fertilized (IVF), and cultured in CR1aa (IVC) for examination of their development to the blastocyst stage (Kubota et al. 1998 Mol. Reprod. Dev. 51, 281–286). Fresh oocytes without IVS were used as controls. The nuclear status of oocytes after IVS–IVM was compared to that of control oocytes by aceto-orcein stain. Their developmental rates to the blastocyst stage after IVM–IVF–IVC were compared between experimental and control groups. The experiment was repeated more than 3 times, and results were statistically analyzed using Student's t-test. When bFF and PBS supplemented with FBS or PVA were used for IVS, the rates of survived COCs after IVS and the development to the blastocyst stage after IVM–IVF–IVC (bFF (n = 87): 0&percnt;, 0&percnt;; PBS/FBS (n = 72): 84&percnt;, 1&percnt;; and PBS/PVA (n = 81): 89&percnt;, 6&percnt;, respectively) were significantly lower than those of the control group (n = 406; 97&percnt; and 29&percnt;, respectively). On the other hand, when M199A supplemented with FBS or PVA was used for IVS, the survival rate after IVS and the developmental rate to the blastocyst stage after IVS–IVM–IVF (M199A/FBS (n = 97): 82&percnt;, 28&percnt;; and M199A/PVA (n = 111): 98&percnt;, 31&percnt;, respectively) did not differ from those of the control group. After IVS, cumulus expansion was not seen and most of the oocyte nuclei reached the GVBD stage. These results suggest that the nuclear maturation progress of bovine oocytes can be regulated for at least 22 h in M199A without any deleterious influence on the number of oocytes surviving at an immature state after the storage and their subsequent development to the blastocyst stage after IVM–IVF–IVC. The delayed maturation allows a flexible fertilization schedule which is advantageous in research and industrial applications.

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44 IN VITRO DEVELOPMENT OF INTERSPECIES NUCLEAR TRANSFER EMBRYOS GENERATED WITH BOVINE OOCYTES AND EQUINE SKIN FIBROBLASTS

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab44 ◽

2011 ◽

Vol 23 (1) ◽

pp. 128

Author(s):

J. Lee ◽

J. Park ◽

Y. Chun ◽

W. Lee ◽

K. Song

Keyword(s):

Nuclear Transfer ◽

Polar Body ◽

Donor Cell ◽

Skin Fibroblasts ◽

Developmental Competence ◽

Cleavage Rate ◽

Cell Stage ◽

Bovine Oocytes

Study for equine somatic cell nuclear transfer (SCNT) is an attractive field for research, but it has not been a major field of study because it is hard to obtain a sufficient number of ovaries and it takes a lot of time and effort for the recovery of oocytes matured in vivo by ovum pickup. It was reported that the bovine cytoplast could support the remodelling of equine donor cells (Zhou et al. 2007 Reprod. Domest. Anim. 42, 243–247). The objectives of this study are 1) to monitor the early events of equine SCNT by interspecies SCNT (isSCNT) between bovine cytoplast and equine donor cell, and 2) to investigate the developmental competence of isSCNT embryos. Bovine oocytes were recovered from the follicles of slaughtered ovaries, and matured in TCM-199 supplemented with 10 mU mL–1 FSH, 50 ng mL–1 EGF, and 10% FBS at 39°C under 5% CO2 in air for 22 h. Fibroblasts derived from bovine or equine skin tissues were synchronized at G0/G1 stage by contact inhibition for 72 h. After IVM, oocytes with polar body were enucleated and electrically fused with equine or bovine skin fibroblasts (1.0 kV cm–1, 20 μs, 2 pulses). Fused couplets were activated with 5 μM ionomycin for 4 min followed by 5 h culture in 10 μg mL–1 cycloheximide (CHX) and/or 2 mM 6-DMAP, and cultured in modified synthetic oviduct fluid (mSOF) at 39°C under 5% CO2, 5% O2, and 90% N2 for 7 days. All analyses were performed using SAS (version 9.1; SAS Institute, Cary, NC, USA). The cleavage rate of isSCNT embryos derived from equine cell was not different (252/323, 78.7%; P = 0.94) from that of SCNT embryos derived from bovine cell (230/297, 79.2%). However, the rate of isSCNT embryos developed to over 8-cell stage was lower (3.3%; P < 0.0001) than that of bovine SCNT embryos (39.4%), and total cell number of isSCNT embryos developed to over 8-cell stage was lower (17.5, n = 12; P < 0.0001) than that (80.8, n = 110) of bovine SCNT embryos. Also, the rate of blastocyst formation of isSCNT embryos (0/323; 0.0%) was lower (P < 0.0001) than that of bovine SCNT embryos (83/297; 29.3%). Meanwhile, reconstructed oocytes for isSCNT were fixed at 8 h after activation to investigate the formation of pseudo-pronucleus (PPN) after post-activation treatment with CHX or CHX+6-DMAP. The ratio of oocytes with single PPN after treatment with CHX+6-DMAP (26/35; 74.3%) was not different (P = 0.63) from that of oocytes treated with CHX (24/36; 68.1%). Although isSCNT embryos derived from bovine cytoplast and equine donor cell could not develop to more than the 16-cell stage, it is believed that the results of this isSCNT study could be used for the preliminary data regarding the reprogramming of donor cell in equine SCNT.

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Generation of parthenogenetic goat blastocysts: effects of different activation methods and culture media

Zygote ◽

10.1017/s0967199413000580 ◽

2014 ◽

Vol 23 (3) ◽

pp. 327-335 ◽

Cited By ~ 5

Author(s):

Hruda Nanda Malik ◽

Dinesh Kumar Singhal ◽

Shrabani Saugandhika ◽

Amit Dubey ◽

Ayan Mukherjee ◽

...

Keyword(s):

Culture Media ◽

Combined Treatment ◽

Blastocyst Stage ◽

Developmental Competence ◽

Cleavage Rate ◽

Cell Stage ◽

Quantitative Expression ◽

Pattern Of Variation ◽

Better Than

SummaryThe present study was carried out to investigate the effects of different activation methods and culture media on the in vitro development of parthenogenetic goat blastocysts. Calcium (Ca2+) ionophore, ethanol or a combination of the two, used as activating reagents, and embryo development medium (EDM), modified Charles Rosenkrans (mCR2a) medium and research vitro cleave (RVCL) medium were used to evaluate the developmental competence of goat blastocysts. Quantitative expression of apoptosis, stress and developmental competence-related genes were analysed in different stages of embryos. In RVCL medium, the cleavage rate of Ca2+ ionophore-treated oocytes (79.61 ± 0.86) was significantly (P < 0.05) higher than in ethanol (74.90 ± 1.51) or in the combination of both Ca2+ ionophore and ethanol. In mCR2a or EDM, hatched blastocyst production rate of Ca2+ ionophore-treated oocytes (8.33 ± 1.44) was significantly higher than in ethanol (6.46 ± 0.11) or in the combined treatment (6.70 ± 0.24). In ethanol, the cleavage, blastocyst and hatched blastocyst production rates in RVCL medium (74.90 ± 1.51, 18.30 ± 1.52 and 8.24 ± 0.15, respectively) were significantly higher than in EDM (67.81 ± 3.21, 14.59 ± 0.27 and 5.59 ± 0.42) or mCR2a medium (65.09 ± 1.57, 15.36 ± 0.52 and 6.46 ± 0.11). The expression of BAX, Oct-4 and GlUT1 transcripts increased gradually from 2-cell stage to blastocyst-stage embryos, whereas the transcript levels of Bcl-2 and MnSOD were significantly lower in blastocysts. In addition, different activation methods and culture media had little effect on the pattern of variation and relative abundance of the above genes in different stages of parthenogenetic activated goat embryos. In conclusion, Ca2+ ionophore as the activating agent, and RVCL as the culture medium are better than other tested options for development of parthenogenetic activated goat blastocysts.

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Birth of rats following nuclear exchange at the 2-cell stage

Zygote ◽

10.1017/s0967199403002375 ◽

2003 ◽

Vol 11 (4) ◽

pp. 317-321 ◽

Cited By ~ 10

Author(s):

Sangho Roh ◽

Jitong Guo ◽

Nakisa Malakooti ◽

John R. Morrison ◽

Alan O. Trounson ◽

...

Keyword(s):

Nuclear Transfer ◽

Blastocyst Stage ◽

Developmental Competence ◽

Perivitelline Space ◽

Sprague Dawley ◽

Cell Stage ◽

Rat Embryos ◽

Sprague Dawley Rats ◽

Nuclear Exchange

We report full-term development of nuclear transfer embryos following nuclear exchange at the 2-cell stage. Nuclei from 2-cell rat embryos were transferred into enucleated 2-cell embryos and developed to term after transfer to recipients (NT2). Pronuclear exchange in zygotes was used for comparison (NT1). Zygotes and 2-cell embryos were harvested from 4-week-old female Sprague-Dawley rats. Nuclear transfer was performed by transferring the pronuclei or karyoplasts into the perivitelline space of recipient embryos followed by electrofusion to reconstruct embryos. Fused couplets were cultured for 4 or 24 h before being transferred into day 1 pseudopregnant recipients (Hooded Wistar) at the 1- or 2-cell stage. In vitro culture was also carried out to check the developmental competence of the embryos. In vitro development to the blastocyst stage was not significantly different between the two groups (NT1, 34.3%; NT2, 45.0%). Two of three recipients from NT1 and two of five recipients from NT2 became pregnant. Six pups (3 from NT1, 3 from NT2) were delivered from the four foster mothers. Three female pups survived; 2 from NT1 and 1 from NT2. At 2 months of age these pups appeared healthy, and were mated with Sprague-Dawley males. One rat derived from NT1 delivered 15 pups (5 males, 10 females) as did the rat from NT2 (7 males, 8 females). Our results show that by using karyoplasts from 2-cell stage embryos as nuclear donors and reconstructing them with enucleated 2-cell embryos, healthy rats can be produced.

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43IMPROVED IN VITRO DEVELOPMENT OF PORCINE NUCLEAR TRANSFER EMBRYOS WITH 6-DMAP FOLLOWING FUSION

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab43 ◽

2004 ◽

Vol 16 (2) ◽

pp. 144

Author(s):

G.-S. IM ◽

L. Lai ◽

Z. Liu ◽

Y. Hao ◽

C.M. Murphy ◽

...

Keyword(s):

Nuclear Transfer ◽

Electric Pulse ◽

Developmental Rate ◽

Cell Number ◽

Blastocyst Stage ◽

In Vitro Development ◽

Electric Pulses ◽

Developmental Rates ◽

Vitro Development

Although nuclear transfer (NT) has successfully produced cloned piglets, the development to blastocyst and to term is still low. Activation of the NT embryos is one of the key factors to improve the developmental ability of porcine NT embryos. Electric pulses as well as chemicals have been used to activate porcine NT embryos. This study was conducted to investigate the effect of continued activation following fusion pulses on in vitro development of porcine NT Embryos. Oocytes derived from a local abattoir were matured for 42 to 44h and enucleated. Ear skin cells were obtained from a 4-day-old transgenic pig transduced with eGFP recombinant retrovirus. Enucleated oocytes were reconstructed and cultured in PZM-3 in a gas atmosphere of 5% CO2 in air. Cleavage and blastocyst developmental rates were assessed under a stereomicroscope on Day 3 or 6. Blastocysts were stained with 5μg of Hoechst 33342 and total cell number was determined with an epifluorescent microscope. In Experiment 1, oocytes were activated with two 1.2kV/cm for 30μs (E) in 0.3M mannitol supplemented with either 0.1 or 1.0mM Ca2+. In each treatment, activated oocytes were divided into three groups. The first group was control (E). Other two groups were exposed to either ionomycin and 6-DMAP (E+I+D) or 6-DMAP (E+D) immediately after the electric pulses. In Experiment 2, fusion was conducted by using 1.0mM Ca2+ in the fusion medium. Fused NT embryos were divided into three treatments. NT embryos were fused and activated simultaneously with electric pulse as a control (C); the second group was treated with 6-DMAP immediately after fusion treatment (D0); and the third group was treated with 6-DMAP at 20min (D20) after fusion. In experiment 1, for 0.1mM Ca2+, developmental rates to the blastocyst stage for E, E+I+D or E+D were 12.5, 26.7 and 22.5%, respectively. For 1.0mM Ca2+, developmental rates to the blastocyst stage were 11.4, 28.3 and 35.6%, respectively. The activated oocytes treated with 6-DMAP following the electric pulses by using 1.0mM Ca2+ in fusion medium had higher (P<0.05) developmental rates to the blastocyst stage. In Experiment 2, developmental rates to the blastocyst stage for C, D0 or D20 were 10.0, 12.3, and 19.9%, respectively. Developmental rate to the blastocyst stage was higher (P<0.05) in D20. Fragmentation rates were 19.9, 10.8, and 9.0%, respectively. Regardless of Ca2+ concentration in fusion medium, continued treatments with chemicals following electric pulses supported more development of porcine activated oocytes. Treating NT embryos with 6-DMAP alone after fusion was completed by using 1.0mM Ca2+ in fusion medium improved the developmental rates to the blastocyst stage and prevented fragmentation accompanied by electric fusion. This study was supported by NIH NCRR 13438 and Food for the 21st Century.

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205.The effect of FSH concentration during IVM and gamete co-incubation length during IVF on the development of unstimulated prepubertal ewe oocytes

Reproduction Fertility and Development ◽

10.1071/srb04abs205 ◽

2004 ◽

Vol 16 (9) ◽

pp. 205 ◽

Cited By ~ 2

Author(s):

K. M. Morton ◽

W. M. C. Maxwell ◽

G. Evans

Keyword(s):

Blastocyst Stage ◽

Developmental Competence ◽

Blastocyst Formation ◽

In Vitro Development ◽

Oocyte Collection ◽

Chi Squared ◽

Development In Vitro ◽

Stage 1 ◽

Vitro Development

The developmental competence of prepubertal oocytes can be increased by the administration of gonadotrophins prior to oocyte collection (1); but this is not possible with abattoir-sourced oocytes, and modifications to the IVP system may increase in vitro development. Experiments were conducted to determine the effects of FSH concentration (10, 20 or 60 μg mL-1) during IVM (5 replicates) and gamete co-incubation length (short: 2-3 h, long: 18-20 h) during IVF (6 replicates) on subsequent embryonic development. For both experiments ovaries were collected from prepubertal lambs (16-24 weeks) slaughtered at an abattoir and embryos produced in vitro (1). Data were analysed by chi-squared test. Oocyte cleavage at 48 hours post-insemination (hpi) was higher for oocytes matured in medium containing 20 (60/77; 77.9%) and 60 (56/73; 76.7%) than 10 μg mL-1 (40/67; 59.7%) FSH. Blastocyst formation (% cultured oocytes) on Day 7 (Day 0 = IVF) was higher for oocytes matured with 20 (31/77; 40.3%) than 10 (16/67; 23.9%) or 60 μg mL-1 (20/73; 27.4%). Oocyte cleavage at 48 hpi was reduced for short (36/57; 63.2%) compared with long (49/55; 89.1%) co-incubation, although blastocyst formation (% cultured oocytes; Day 7) did not differ between groups (22/57; 38.6% and 23/55; 41.8%, respectively). These results demonstrate that increasing the FSH concentration above normal levels during IVM of prepubertal lamb oocytes improves development in vitro. Gamete co-incubation length did not influence the proportion of oocytes progressing to the blastocyst stage. (1) Morton et al. (2003) Proc. Soc. Reprod. Fert. P18.

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152EFFECT OF REPLACEMENT OF PYRUVATE/LACTATE IN CULTURE MEDIUM WITH GLUCOSE ON PREIMPLANTATION DEVELOPMENT OF PORCINE EMBRYOS IN VITRO

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab152 ◽

2004 ◽

Vol 16 (2) ◽

pp. 198

Author(s):

N.W.K. Karja ◽

S. Medvedev ◽

D. Fuchimoto ◽

A. Onishi ◽

M. Iwamoto ◽

...

Keyword(s):

Energy Source ◽

Cell Number ◽

Blastocyst Stage ◽

Developmental Competence ◽

Culture Period ◽

Blastocyst Formation ◽

Cell Stage ◽

Energy Substrates ◽

Anova Test

Kikuchi et al. (2002 Biol. Reprod. 66, 1033–1041) reported that replacement of pyruvate and lactate with glucose, as energy substrates, at 48h of culture in IVC medium enhanced the quality of IVP porcine blastocysts. However, the exact time during early cleavage stages when the utilization of glucose as an energy source is optimal has not yet been determined. The purpose of this study was to examine the effects of glucose supplementation at different times of culture on the developmental competence of IVP porcine embryos. Porcine cumulus-oocytes complexes were matured in modified NCSU-37 solution and fertilized in vitro according to Kikuchi et al. All cultures were performed at 38.5°C, 5% O2, 5% CO2, and 90% N2. In experiment 1, after being fertilized (Day 0), putative zygotes (1158 in 6 trials) were cultured in NCSU-37 supplemented with 0.4% BSA, 0.17mM sodium pyruvate, and 2.73mM sodium lactate (IVC-pyr/lac). Embryos (30–50 in each group) were then transferred into NCSU-37 supplemented with 0.4% BSA and 5.55mM D-glucose (IVC-glu) at 24, 48, 72, 96, or 118h of culture. As control groups, putative zygotes (391) were cultured in IVC-pyr/lac or IVC-glu for the whole culture period. In experiment 2, after being fertilized, putative zygotes (543 in 4 trials, 30–50 in each group) were cultured in IVC-pyr/lac, and then were transferred into IVC-glu at 48h, 53h, 58h, or 63h of culture, because glycolytic activity of in vitro-derived porcine embryos was reported to increase around the 8-cell stage, and some embryos develop to that stage before 72h of culture in experiment 1. All embryos were cultured for 6 days, and then development to the blastocyst stage and number of cells per blastocyst were assessed. When IVF embryos were cultured in IVC pyr/lac for 24h or 48h and subsequently in IVC-glu until day 6 in experiment 1, the rates of blastocyst formation were significantly higher (P<0.05, ANOVA test) than those of embryos cultured in IVC-pyr/lac for the whole culture period (24.4% and 23.0% v. 14.5%, respectively). However, when IVC pyr/lac was replaced with IVC-glu, there were no significant differences between the energy source replacement groups and the glucose-only group in terms of the proportions of cleavage, development to the blastocyst stage and mean cell number per blastocyst (P>0.05, ANOVA test) (15.2%–24.4%, and 16.8%, respectively). Replacement of pyruvate and lactate with glucose at 58h of culture in experiment 2 significantly enhanced the rate of blastocyst formation (P<0.05, ANOVA test) but not the mean cell number compared with zygotes in which the replacement was done at 48, 53, and 63h of culture (31.3% v. 20.6%, 20.8%, and 21.1%, respectively) (P<0.05, ANOVA test). In conclusion, replacement of pyruvate and lactate with glucose as energy substrates was optimal at 58h of culture for the in vitro development of pig embryos to the blastocyst stage.

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The effect of insemination methods on in vitro maturation outcomes

Clinical and Experimental Reproductive Medicine ◽

10.5653/cerm.2019.03300 ◽

2020 ◽

Vol 47 (2) ◽

pp. 130-134

Author(s):

Pallop Pongsuthirak

Keyword(s):

Polycystic Ovary ◽

Implantation Rate ◽

Fertilization Rate ◽

Blastocyst Stage ◽

Clinical Pregnancy ◽

Developmental Competence ◽

Assisted Reproductive Treatment ◽

Maturation Rate ◽

A Prospective Study

Objective: The aim of this study was to compare the effects of conventional insemination (in vitro fertilization [IVF]) and intracytoplasmic sperm injection (ICSI) on the fertilization, developmental competence, implantation potential, and clinical pregnancy rate of embryos derived from in vitro matured oocytes of patients with polycystic ovary syndrome (PCOS).Methods: A prospective study was carried out among 38 PCOS patients who had undergone in vitro maturation (IVM) treatment. In total, 828 immature oocytes were collected from 42 cycles and randomly assigned for insemination by IVF (416 oocytes) or ICSI (412 oocytes). After fertilization, the embryos were cultured until the blastocyst stage and single embryos were transferred after endometrial preparation and under ultrasound guidance.Results: No significant differences were found in the maturation rate (78.1% vs. 72.6% for IVF and ICSI insemination, respectively; p= 0.076), fertilization rate (59.4% vs. 66.9% for IVF and ICSI insemination, respectively; p= 0.063), or the formation of good-quality blastocysts (40.9% vs. 46.5% for IVF and ICSI insemination, respectively; p= 0.314). Implantation and clinical pregnancy also did not show significant differences.Conclusion: There was a comparable yield of in vitro matured oocytes derived from PCOS patients in terms of fertilization, blastocyst formation, implantation rate, and clinical pregnancy between IVF and ICSI insemination. These findings provide valuable insights for choosing assisted reproductive treatment in women with PCOS, as IVM offers promising outcomes and is less invasive and less costly.

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