scholarly journals Developmental Competence of Early Stage Porcine Embryos Cultured in Medium with Different Energy Substrate in vitro

2015 ◽  
Vol 11 (1) ◽  
Author(s):  
Ni Wayan Kurniani Karja ◽  
Kazuhiro Kikuchi ◽  
Mokhamad Fahrudin

To elucidate the effect of energy requirement during the early embryonic development on their developmentalability to develop to blastocyst stage, in vitro fertilized (IVF) porcine one-cell embryos were cultured in modifiedNorth Carolina State University (NCSU)-37 supplemented with different energy substrate. Result indicated that thecleavage rate of embryos in Pyr-Lac and Gluc-Pyr-Lact groups was significantly higher than in those in Gluc groupand Gluc-Rib group (P < 0.05). At Day 6 of culture, the highest proportion of embryos develop to the blastocyst stagewas obtained in the presence of pyruvate-lactate only. In the medium with glucose, the addition of pyruvate-lactateor ribose slightly increased the proportion of embryos develop to the blastocyst stage, however the value were notsignificantly different form those obtained in the presence of glucose only. The mean cell number in blastocystsderived from Pyr-Lac and Gluc-Pyr-Lact groups were significantly higher than those in the Gluc group (P < 0.05).These results indicated that the presence of glucose only, as energy substrate, during the first 2 days of in vitro culture(IVC) caused a decrease in development of in vitro produced (IVP) porcine embryos to the blastocyst stage and meancell number in blastocysts .Keywords: porcine embryos-energy substrate-in vitro culture

2014 ◽  
Vol 26 (1) ◽  
pp. 123
Author(s):  
Y. Liu ◽  
A. Lucas-Hahn ◽  
B. Petersen ◽  
R. Li ◽  
P. Hassel ◽  
...  

Two nuclear transfer (NT) techniques are routinely used to produce cloned animals, traditional cloning (TC) and handmade cloning (HMC). The TC embryos keep their zona and can be transferred at early stages, whereas HMC embryos are zona-free and must be cultured to the morula/blastocyst stage before transfer. Some studies have shown that in vitro culture reduces embryo development and quality, but it is not known whether embryos produced by TC or HMC differ because of the NT method or the in vitro culture. Therefore, we investigated the developmental competence and histone acetylation (H3K18ac) of porcine NT embryos produced by TC and HMC with (Day 5 and 6) or without (Day 0) in vitro culture. Nuclear transfer experiments were performed on same day (Day 0), using same batch of porcine oocytes and donor cells and same in vitro culture conditions. Cloning procedures were previously described (TC : Cloning Stem Cells 10 : 355; HMC : Zygote 20 : 61). Parthenogenetically activated embryos (PA) were used as control of activation and culture conditions. Embryos from all groups were collected for immunostaining of H3K18ac on Days 0, 5, and 6. The normalized H3K18ac level was calculated as previously described (Epigenetics 6 : 177). Cell numbers per blastocyst in each group were counted on Days 5 and 6. The cleavage rate (Day 2) and blastocyst rates (Days 5 and 6) between groups were analysed by Chi-squared test, whereas cell number per blastocysts and H3K18ac level between groups and days were analysed by ANOVA (SAS version 9.2; SAS Institute Inc., Cary, NC, USA). Cleavage rate of HMC embryos was lower than that of TC embryos, but blastocyst rate and cell number per blastocyst were higher in the HMC group compared with TC (Table 1). Differences of H3K18ac level between HMC, TC, and PA groups were only observed on Day 6 but not on Day 0 or Day 5. Within HMC and TC groups, there was no difference in H3K18ac level between Day 0 and Day 5, but the level was lower on Day 6 compared with Day 5 in the HMC group, whereas the TC group displayed the opposite pattern. In conclusion, NT embryos produced by HMC show higher blastocyst rate and cell number per blastocyst compared with TC embryos. Both in vitro culture and the NT method result in differences of the normalized H3K18ac levels. Further study is needed to investigate putative differences between NT embryos produced by HMC and TC compared to in vivo embryos also after transfer to recipients. Table 1.Cleavage and blastocyst rate, cell numbers, and normalized H3K18ac level for handmade cloning (HMC), traditional cloning (TC), and parthenogenetically activated (PA) embryos1


2002 ◽  
Vol 14 (5) ◽  
pp. 291 ◽  
Author(s):  
N. W. Kurniani Karja ◽  
Takeshige Otoi ◽  
Masako Murakami ◽  
Minori Yuge ◽  
Mokhamad Fahrudin ◽  
...  

The effects of protein supplementation in culture medium on development to the hatching and hatched blastocyst stages of cat in vitro-fertilized embryos were investigated. In the first experiment, presumptive zygotes derived from in vitro maturation and in vitro fertilization (IVF) were cultured in modified Earle's balanced salt solution (MK-1) supplemented with 0.4% bovine serum albumin (BSA) or 5% fetal bovine serum (FBS) for 9 days. There were no significant differences between the BSA and FBS groups with respect to the proportion of cleavage and development to the morula and blastocyst stages of zygotes. However, the presence of FBS in the medium enhanced development to the hatching blastocyst stage of zygotes compared with the BSA group (31.4% v. 7.8%). Moreover, 2.9% of zygotes cultured with FBS developed to the hatched blastocyst stage. The mean cell number of blastocysts derived from zygotes cultured with FBS was significantly higher (P&lt;0.01) than that from zygotes cultured with BSA (136.6 v.101.5). In the second experiment, embryos at the morula or blastocyst stage, which were produced by culturing in MK-1 supplemented with 0.4% BSA after IVF, were subsequently cultured in MK-1 with 0.4% BSA or 5% FBS. Significantly more morulae developed to the blastocyst (P&lt;0.05) and hatching blastocyst stages (P&lt;0.01) in the FBS group than in the BSA group (71.5% and 53.6% v. 44.9% and 6.0%, respectively). Although none of the morulae cultured with BSA developed to the hatched blastocyst stage, 11.5% of morulae cultured with FBS developed to the hatched blastocyst stage. Moreover, the proportion of development to the hatching blastocyst stage of blastocysts was significantly higher (P&lt;0.01) in the FBS group than in the BSA group (68.7% v. 9.8%). None of the blastocysts cultured with BSA developed to the hatched blastocyst stage, whereas 7.3% of blastocysts cultured with FBS developed to the hatched blastocyst stage. The results of the present study indicate that supplementation with FBS at different stages of early embryo development promotes development to the hatching and hatched blastocyst stages of cat IVF embryos.


2004 ◽  
Vol 16 (2) ◽  
pp. 198
Author(s):  
N.W.K. Karja ◽  
S. Medvedev ◽  
D. Fuchimoto ◽  
A. Onishi ◽  
M. Iwamoto ◽  
...  

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&lt;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&gt;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&lt;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&lt;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.


2008 ◽  
Vol 20 (1) ◽  
pp. 102
Author(s):  
N. Maedomari ◽  
K. Kikuchi ◽  
M. Fahrudin ◽  
N. Nakai ◽  
M. Ozawa ◽  
...  

Metaphase-II chromosome transfer (M-II transfer) of oocytes is considered to be one of the advanced procedures to improve fertilization and developmental abilities of oocytes with poor cytoplasmic maturation. The aim of this study was to investigate the developmental capacity after IVF and IVC of porcine oocytes reconstructed from karyoplasts and cytoplasts produced by centri-fusion (Fahrudin et al. 2007 Cloning Stem Cells 9, 216–228). In brief, IVM oocytes (Kikuchi et al. 2002 Biol. Reprod. 66, 1033–1041) with a visible first polar body were centrifuged at 13 000g for 9 min to stratify the cytoplasm. Then the zonae pellucidae were removed with pronase treatment. Zona-free oocytes were layered on a 300-µL discontinuous gradient of Percoll in TCM-HEPES with 5 µg mL–1 of cytochalasin B. After centrifugation at 6000g for 4 s, fragmented cytoplasms with approximately equal volumes were obtained, stained with Hoechst-33342, and classified into cytoplasm with (K; karyoplast) or without (C; cytoplast) chromosomes. One karyoplast was fused with 0, 1, 2, 3, and 4 cytoplasts (K, K + 1C, K + 2C, K + 3C, and K + 4C, respectively) by an electric stimulation with a single DC pulse (1.5 kV cm–1 for 20 µs) and cultured for 1 h. Zona-free oocytes without any reconstruction served as control oocytes. The diameters of the reconstructed and control oocytes were measured. All specimens were fertilized in vitro with frozen–thawed boar sperm, and cultured using the well of the well (WOW) system (Vajta et al. 2000 Mol. Reprod. Dev. 55, 256–264). Their fertilization status and developmental competence were examined. Data were analyzed by ANOVA followed by Duncan's multiple range tests. The diameter differed significantly among K to K + 4C oocytes (75.0–127.1 µm; P < 0.05), whereas the diameter of K + 2C oocytes was similar to that of the control oocytes (110.5 µm). Regardless of the cytoplast volume, sperm penetration rates (73.1–93.8%) for K to K + 4C oocytes were not significantly different compared to control oocytes (78.0%). Male pronuclear formation rates of K to K + 4C oocytes (92.3–97.1%) were also not different significantly different compared to control oocytes (96.6%). However, monospermy rates of K oocytes was significantly higher (61.6%; P < 0.05) than those of the reconstructed (K + 1C to K + 4C; 18.2–34.9%) and control oocytes (32.9%). The blastocyst formation rates in K, K + 1C, K + 2C, and K + 3C groups (0.0–9.8%; P < 0.05) were significantly lower than those in the control and K + 4C groups (17.8% and 15.3%, respectively; P < 0.05). The total cell numbers per blastocyst in K + 1C and K + 2C groups (7.5 and 8.3 cells, respectively) were significantly lower than in the control, K + 3C, and K + 4C groups (15.3–26.2 cells; P < 0.05). These results suggest that the cytoplast volume of porcine M-II transferred oocytes, produced by reconstruction from a karyoplast and cytoplast(s) and centri-fusion, is important for their ability to develop to the blastocyst stage and influences cell number.


Zygote ◽  
2018 ◽  
Vol 27 (1) ◽  
pp. 36-45
Author(s):  
Jaqueline Sudiman ◽  
Alice Lee ◽  
Kheng Ling Ong ◽  
Wu Zi Yuan ◽  
Sarah Jansen ◽  
...  

SummaryMouse and lamb oocytes were vitrified with, or exposed to, different cryoprotectants and evaluated for their effects on their survival and developmental competence after in vitro fertilization (IVF) and activation treatments. Control oocytes remained untreated, whilst the remainder were exposed to three different combinations of vitrification solutions [dimethyl sulfoxide (DMSO) + ethylene glycol (EG), EG only, or propanediol (PROH) + EG] and either vitrified or left unfrozen (exposed groups). Oocytes in the control and vitrified groups underwent IVF and developmental competence was assessed to the blastocyst stage. In lambs, survival rate in vitrified oocytes was significantly lower than for oocytes in the exposed groups (P <0.05). Blastocyst development was low in vitrified oocytes compared with controls (<6% vs 38.9%, P <0.01). Parthenogenetic activation was more prevalent in vitrified lamb oocytes compared with controls (P <0.05). No evidence of zona pellucida hardening or cortical granule exocytosis could account for reduced fertilization rates in vitrified lamb oocytes. Mouse oocytes demonstrated a completely different response to lamb oocytes, with survival and parthenogenetic activation rates unaffected by the vitrification process. Treatment of mouse oocytes with DMSO + EG yielded significantly higher survival and cleavage rates than treatment with PROH + EG (87.8% and 51.7% vs 32.7% and 16.7% respectively, P <0.01), however cleavage rate for vitrified oocytes remained lower than for the controls (51.7% vs 91.7%, P <0.01) as did mean blastocyst cell number (33 ± 3.1 vs 42 ± 1.5, P <0.05). From this study, it is clear that lamb and mouse show different tolerances to cryoprotectants commonly used in vitrification procedures, and careful selection and testing of species-compatible cryoprotectants is required when vitrifying oocytes to optimize survival and embryo development.


2013 ◽  
Vol 25 (1) ◽  
pp. 265
Author(s):  
K. Knauer ◽  
H. Stinshoff ◽  
S. Wilkening ◽  
C. Wrenzycki

It is known that the progesterone (P4) provided by the corpus luteum is essential for the maintenance of pregnancy. It has been suggested that supplying external P4 in vivo is beneficial to the establishment and upkeep of pregnancy. The aim of the present study was to assess the effects of supplementation with different concentrations of P4 on either of 2 days of in vitro culture (IVC) on early bovine embryo development in an in vitro model. A total of 5073 cumulus–oocyte complexes were matured and fertilized in vitro. Before culture, they were collected in groups of 30 and allocated to 1 of 9 groups. The groups were supplemented with 10, 20, or 100 ng of P4 on Days 4 or 5 of IVC (IVF = Day 0). Alcohol (ETOH) was used as the solvent, so 8 µL of ETOH was used per supplementation. Therefore, two additional groups were supplemented with only ETOH on Day 4 or 5 of IVC. The presumptive zygotes allocated to group 9 were not supplemented. A culture system without oil overlay was used to prevent the lipophilic P4 from moving into the oil. Embryo cleavage and development rates were determined solely on Day 8 of IVC. Single expanded blastocysts were stored at –80°C for RT-qPCR. Subsequently, the relative amounts of six developmentally important gene transcripts (IGF1R, SLC2A1, HSD3B1, IFNT, PGRMC1, and PGRMC2) were analysed in single embryos of all groups. Statistical analysis was performed using one-way and two-way ANOVA, and the level of significance was set at P ≤ 0.05. Cleavage and development rates did not differ among groups (see Table 1). The relative abundance of IGF1R, SLC2A1, PGRMC1, and PGRMC2 was not affected by either the concentration or the timing of P4 supplementation. Nevertheless, there was a statistically significant interaction between the day of treatment and the concentration used for the expression of HSD3B1 mRNA. When 20 ng of P4 was added on Day 5 of IVC, significantly more HSD3B1 transcripts were detected than if 10 ng, 100 ng, or ETOH alone was added. The expression of IFNT was not affected by the day of supplementation, only by the concentration used. Thus, supplementation with 20 ng of P4 resulted in a significantly higher level of transcripts than when 10 ng or ETOH was supplemented. The results indicate that the amount of P4 present during early embryonic development and the timing of its presence had an impact on molecular developmental competence. However, no effects concerning morphological development up to the blastocyst stage could be detected. Table 1.Cleavage and development rates (± SEM) of embryos supplemented with 10, 20, or 100 ng on Day 4 or 5 of in vitro culture (P ≥ 0.05) The financial support of the FBF e.V. is acknowledged.


2018 ◽  
Vol 30 (1) ◽  
pp. 205 ◽  
Author(s):  
R. Emmerstorfer ◽  
K. Radefeld ◽  
V. Havlicek ◽  
U. Besenfelder ◽  
H. Yu ◽  
...  

The aim of this work was to establish an in vitro culture approach using bovine oviducal fluid (OF) to improve embryo quality and to provide an in vitro system to study oviduct function. Bovine oviducts ipsilateral to ovulation were collected at the slaughterhouse, 1 to 4 days after ovulation. The OF was collected by flushing the oviducts with 1 mL of Charles Rosenkrans 1 medium (CR1). Samples from 21 oviducts were pooled and proteins were concentrated using centrifugal filter devices. Aliquots of 3 different protein concentrations, determined by Bradford assay, were prepared and stored at –20°C. Abattoir-retrieved cumulus–oocyte complexes were used for standard in vitro maturation (IVM) and IVF (Day 0). On Day 1, presumptive zygotes (n = 1498) were randomly allocated to 4 different culture groups and cultured up to Day 9. The presumptive zygotes of the control group (n = 364) were cultured in CR1 with 5% oestrous cow serum (OCS) supplemented with 1 mg mL−1 hyaluronan. In the experimental groups, OCS was replaced by OF, resulting in 3 groups with final protein concentrations of 0.1 mg mL−1 (n = 380), 0.5 mg mL−1 (n = 380) or 1 mg mL−1 (n = 374). Cleavage rate was recorded on Day 2 and blastocyst yield on Days 7, 8, and 9 after fertilization. On Day 7, blastocysts were removed and either stained (Hoechst 33342) for cell number or subjected to a slow freezing protocol using 1.5 M ethylene glycol. After thawing, the re-expansion and hatching rate of blastocysts were determined at 24, 48 and 72 h. Eight replicates were carried out and data were analysed by ANOVA. Cleavage rate increased with increasing protein concentration (0.1 mg mL−1: 80.9 ± 4.2%; P > 0.05; 0.5 mg mL−1: 83.4 ± 2.5%; P < 0.1) and was significantly higher in the 1 mg mL−1 group (84.5 ± 4.4%; P < 0.05) compared with the control group (79.7 ± 3.4%). The cumulative blastocyst rate on Day 9 was significantly lower (P < 0.05) in all experimental groups (0.1 mg mL−1: 15.8 ± 8.9%; 0.5 mg mL−1: 18.7 ± 12.0%; 1 mg mL−1: 17.0 ± 11.2%) compared with the control group (34.1 ± 5.4%). The total number of cells was not affected by OF (P > 0.05). There was no significant difference (P > 0.05) in the post-thaw re-expansion rate between the experimental groups (0.1 mg mL−1: n = 26 thawed blastocysts; 0.5 mg mL−1: n = 27; 1 mg mL−1: n = 23) and the control group (n = 58). The post-thaw hatching rate was significantly higher at 24 and 72 h, respectively, in the 0.5 mg mL−1 group (44.4% and 74.1%; P < 0.05) and the 1 mg mL−1 group (47.8%; P < 0.05; and 82.6%; P < 0.01) compared with the control group (18.9% and 44.8%). The replacement of serum with OF during in vitro culture of bovine embryos had a stage specific effect, resulting in higher cleavage rates but lower blastocyst rates. To address this issue, OF will be collected at different stages and applied in the matching in vitro culture phases in future studies. Interestingly, the post-thaw hatching rate was up to twice as high in the experimental groups, indicating better quality of those embryos developing to blastocyst stage.


2016 ◽  
Vol 28 (7) ◽  
pp. 886 ◽  
Author(s):  
Roser Morató ◽  
Míriam Castillo-Martín ◽  
Marc Yeste ◽  
Sergi Bonet

The aim of our study was to assess whether the cryotolerance of in vitro-produced embryos could be influenced by the length of in vitro culture and size of blastocoel cavity before vitrification, using the pig as a model. For this purpose we analysed the cryoresistance and apoptosis rate of blastocysts at different stages of development as derived on Day 5 and 6 of in vitro culture. Blastocysts were subsequently vitrified, warmed and cultured for 24 h. Re-expansion rates were recorded at 3 and 24 h and total cell number and apoptotic cells were determined at 24 h. Day-6 blastocysts showed the highest rates of survival after warming, which indicates higher quality compared with Day-5 blastocysts. Higher re-expansion rates were observed for expanded blastocysts and those in the process of hatching when compared with early blastocysts. Total cell number and apoptotic cells were affected by blastocyst stage, vitrification–warming procedures and length of in vitro culture, as expanding and hatching–hatched blastocysts from Day 6 presented higher percentages of apoptotic cells than fresh blastocysts and blastocysts vitrified at Day 5. Our findings suggest that the cryotop vitrification method is useful for the cryopreservation of porcine blastocysts presenting a high degree of expansion, particularly when vitrification is performed after 6 days of in vitro culture. Furthermore, these results show that faster embryo development underlies higher blastocyst cryotolerance and provide evidence that blastocoel cavity expansion before vitrification is a reliable index of in vitro-produced embryo quality and developmental potential.


Reproduction ◽  
2011 ◽  
Vol 142 (4) ◽  
pp. 517-527 ◽  
Author(s):  
Maria Gracia Catalá ◽  
Dolors Izquierdo ◽  
Svetlana Uzbekova ◽  
Roser Morató ◽  
Montserrat Roura ◽  
...  

The aim of this study was to test the Brilliant Cresyl Blue (BCB) stain to select prepubertal sheep oocytes for in vitro blastocyst production. Oocyte diameter, mitochondrial activity, maturation-promoting factor (MPF) activity and mRNA relative expression (RE) of genes related to metabolism (ATPase Na+/K+ transporting α 1 (ATP1A1) and cytochrome c oxidase subunit 1 (COX1)) and constitutive function of the cell (cytoplasmic polyadenylation-element-binding protein (CPEB) and S100A10) were assessed. Immature oocytes were exposed to different BCB concentrations (13, 26, 39 and 52 μM) and classified according to their cytoplasm colouration as grown BCB+ (blue cytoplasm) and growing BCB− (colourless cytoplasm). Staining oocytes with 13 μM BCB during 60 min allows selection of (BCB+) the largest (123.66 μm) and most competent oocytes to develop to the blastocyst stage (21%) with a higher number of cells (69.71±6.19 s.e.m.) compared with non-stained BCB− oocytes (106.82 μm, 9% and 45.91±3.35 s.e.m. respectively). Mitochondrial activity, assessed by MitoTracker Orange CMTMRos probe, was significantly higher in BCB+ than in BCB− oocytes after in vitro maturation (3369 and 1565 AU respectively). MPF activity was assessed by CDC2 kinase activity assay showing significantly higher activity at metaphase II stage in BCB+ than in BCB− oocytes (1.479±0.09 and 1.184±0.05 optical density respectively). The genes analysed in this work, ATP1A1, COX1, CPEB and S100A10, did not show significant effect in mRNA RE between BCB selected oocytes. In conclusion, BCB stains larger and more competent oocytes to develop to the blastocyst stage with more active mitochondria and MPF activity and higher blastocyst cell number.


2009 ◽  
Vol 21 (1) ◽  
pp. 209 ◽  
Author(s):  
T. Somfai ◽  
Y. Inaba ◽  
Y. Aikawa ◽  
M. Ohtake ◽  
S. Kobayashi ◽  
...  

In in vitro embryo production systems, there is a need to select embryos with good developmental competence at the early stages. This study was conducted to determine whether there was any relationship between the duration of the first 3 cell cycles, the cleavage pattern of the first cell division, and the developmental competence of embryos during in vitro culture. A total of 320 in vitro-matured and in vitro-fertilized bovine oocytes were cultured in microdrops of CR1aa medium supplemented with 5% calf serum covered by mineral oil in 5% CO2 and 20% O2 at 38.5°C. The kinetics of embryo development were measured by time-lapse cinematography. Embryos were classified according to their cleavage pattern at the first cell division. Of 285 cleaved embryos, 119 had 2 blastomeres of the same size (normal cleavage: NC), 49 had 2 blastomeres with multiple small fragments (multiple fragments: MF), 34 had 2 blastomeres and a protrusion (protrusion: PT), 45 showed direct cleavage from 1 cell to 3 or 4 blastomeres (3–4BL), and 60 oocytes cleaved to 2 blastomeres of different sizes (unequal blastomeres: UB). (Twenty-two embryos belonged to 2 classes.) After 175 h of culture, blastocysts were either subjected to differential inner cell mass/trophectoderm (ICM/TE) staining or karyotyped. The first and second cell cycles (mean ± SEM) of viable embryos (that could develop to the blastocyst stage) were significantly shorter than those of nonviable embryos (24.9 ± 0.3 h and 8.7 ± 0.1 h v. 26.6 ± 0.7 h and 10.0 ± 0.1 h, respectively); however, the length of the third cell cycle did not differ (P < 0.05, paired t-test). The duration of 1 cell stage in the NC group was significantly shorter than that of MF, PT, 3–4BL, and UB groups (24.7 ± 0.4 h, 26.6 ± 0.5 h, 26.3 ± 0.6 h, 26.0 ± 0.2 h, and 27.7 ± 0.9 h, respectively). The length of the second and third cell cycles did not differ among the groups. The percentage of NC embryos that developed to the blastocyst stage was similar to that of the 3–4BL group (66.9 and 56.7%, respectively) but was significantly higher than those of the MF, PT, and UB groups (40.5, 26.5, and 35.6%, respectively; P < 0.05, ANOVA). The mean cell numbers of NC blastocysts did not differ from those of the MF, 3–4BL, and UB groups but were higher than those of PT embryos (147.1, 155.6, 121.6, 146.4, and 115.1, respectively). There was no difference in ICM/TE rates between the groups. Unlike NC, MF, PT, and UB embryos, most (6 of 8 karyotyped) 3–4BL blastocysts had abnormal ploidy, such as haploid, triploid, mixoploid, or chaotic chromosome numbers, in blastomeres. Our results revealed that not only the length of the first cell cycles, but also the cleavage pattern during first cell division can be a marker of developmental competence and should be considered for the selection of good-quality embryos for embryo transfer. This work was supported by the Research and Development Program for New Bio-industry Initiatives.


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