220 SYNERGISTIC EFFECT ON EMBRYO DEVELOPMENT BY INCLUSION OF SUPPLEMENTAL EMBRYOS IN AGAR CHIPS

2009 ◽  
Vol 21 (1) ◽  
pp. 208 ◽  
Author(s):  
E. M. Senatore ◽  
M. E. Mannino ◽  
M. V. Suarez Novoa ◽  
J. Xu ◽  
S. Chaubal ◽  
...  

The main scope of this study was to evaluate the likelihood of a helper effect of agar-embedded cleaved embryos on a low number of free embryos at a similar stage of development within the same culture droplet. Such an improved system could be beneficial within ovum pickup/in vitro embryo production (OPU/IVEP) combined protocols whenever a low number of OPU-derived cleaved embryos are produced per donor. Oocytes were recovered from abattoir ovaries, and after in vitro maturation (IVM) and in vitro fertilization (IVF), presumptive zygotes were deprived of cumulus investment and allocated into culture droplets for 24 h. At 48 h from IVF, 4- to 8-cell cleaved embryos were randomly allocated into a control and a treatment group. Control groups consisted of 1, 3, 5, and 10 embryos, respectively, in 50-μL droplets. Treatment groups consisted of 1, 3, and 5 free embryos with the addition of 9, 7, and 5 embryos, respectively, at a similar stage of development embedded in agar chips, so as to reach a total number of 10 cleaved embryos in each culture droplet. Culture was performed for both the control and treatment groups in SOF medium droplets covered with mineral oil, with the supplementation of essential and nonessential amino acids in a controlled gas atmosphere consisting of 5% CO2, 7% O2, and 88% N2 at 39°C. Final embryo output was checked at Day 7 from IVF. When considering only free embryos, the difference in progression to blastocyst development was highly significant between the control and treatment groups: 1) group 1 v. 1 + 9: 6.6 v. 84.3% (P = 0.00000); 2) group 3 v. 3 + 7: 11.1 v. 41.3% (P = 0.00001); 3) group 5 v. 5 + 5: 24.4 v. 42.2% (P = 0.00001). Rate of blastocyst development in the control group containing 10 cleaved embryos was not significantly different from free cleaved embryos in the 3 + 7 (39.2 v. 41.3%, P = 0.71) and 5 + 5 treatment groups (39.2 v. 42.2%, P = 0.54), but was significantly lower when compared with the 1 + 9 treatment group (39.2 v. 84.3%, P = 0.000). For 1, 3, 5, and 10 control group embryos, the numbers of replicates and total cleaved embryos used (n) were 30 (n = 30), 27, (n = 81), 27 (n = 135), and 39 (n = 390), respectively. For the 1 + 9, 3 + 7, and 5 + 5 treatment group embryos, the numbers of replicates and total cleaved embryos used were 32 (n = 32), 29 (n = 87), and 27 (n = 135), respectively. In conclusion, a beneficial effect of agar-embedded embryos on the development of free embryos within the same culture droplet was shown. A striking improvement in late-stage embryo development was particularly evident when considering the 1 v. 1 + 9 control and treatment groups. These results may foster a different strategic approach in in vitro culture to enhance embryo development from highly valuable donors.

2013 ◽  
Vol 25 (1) ◽  
pp. 261 ◽  
Author(s):  
M. A. Stout ◽  
J. R. Saenz ◽  
J. F. Chenevert ◽  
G. T. Gentry ◽  
K. B. Bondioli ◽  
...  

Exposure to seminal plasma may modify the ability of sperm to survive cryopreservation, undergo capacitation, and fertilize oocytes. The present work was designed to compare embryo development after IVF of oocytes with ejaculated and epididymal bovine sperm from bulls previously tested and showing similar responses to freezing. However, we also found that this ejaculated and epididymal sperm differed in their in vitro culture dynamics (capacitation, viability, and auto-acrosome reaction) and ability to fertilize oocytes in vitro. Ejaculated and epididymal sperm were collected from the same fertile mature Holstein bulls (n = 4) by artificial vagina and post-castration retrograde caudal epididymal flush, respectively. Collection of epididymal sperm was conducted 2 weeks after the last collection of ejaculated sperm. After collection, ejaculated and epididymal sperm were cryopreserved and stored in LN until use. Before IVF, a viable sperm population was isolated by centrifugation through a Percoll density gradient. Ejaculated and epididymal sperm were then added to fertilization drops at a final concentration of 1 × 106 mL–1, and IVF was conducted with and without the capacitation agent heparin. Oocytes were washed and randomly assigned to one of four treatment groups (ejaculated ± heparin or epididymal ± heparin). Embryo development was determined at 72 and 186 h after IVF. Differences in the mean values among treatment groups were analysed by one-way ANOVA, followed by the Holm-Sidak pairwise multiple comparisons. Embryo cleavage after IVF using ejaculated sperm without heparin (45.2%) was significantly lower (P < 0.05) than in all other groups. Cleavage rates of ejaculated sperm with heparin (56.9%) and epididymal sperm with (58.1%) and without (57.5%) heparin were found to be similar. No difference was noted between ejaculated and epididymal sperm in blastocyst development, although the inclusion of heparin did significantly (P < 0.01) increase blastocyst development in both ejaculated (9.3 compared with 23.6%) and epididymal sperm (2.5 compared with 23.3%). In conclusion, cryopreserved ejaculated and epididymal sperm collected from the same bulls can be successfully used for the in vitro production of bovine blastocysts without changing the existing protocols. This may increase the efficiency when using epididymal sperm in assisted reproductive techniques.


Zygote ◽  
2017 ◽  
Vol 25 (2) ◽  
pp. 222-230 ◽  
Author(s):  
Daiane L. Bulgarelli ◽  
Alessandra A. Vireque ◽  
Caroline P. Pitangui-Molina ◽  
Marcos F. Silva-de-Sá ◽  
Ana Carolina J. de Sá Rosa-e-Silva

SummaryThis study aimed to evaluate the embryo development competence, the nuclear maturation and the viability of germinal vesicle (GV) and metaphase II (MII) oocytes vitrified by the Cryotop method. Cumulus–oocyte complexes were derived from bovine ovaries and three experiments were conducted. In Experiment 1, GV oocytes were vitrified and underwent in vitro maturation (IVM) or not and their nuclear maturation was assessed by orcein staining. In Experiment 2, GV oocytes and MII oocytes were vitrified or not and the viability was assessed by calcein/ethidium homodimer-1 staining. In Experiment 3, MII oocytes matured before or after vitrification were submitted to in vitro fertilization (IVF) and parthenogenetic activation (PA) in order to evaluate embryo development. No difference was found for the nuclear maturation rate in the GV group (50%) and the GV control group (67%; P = 0.23) and for viability rate (56%; 77%; P = 0.055, respectively). However, in the MII group (27%) viability was significantly lower than that of the MII control group (84%; P < 0.0001). The cleavage rate by IVF and PA was similar in the GV group and the MII group. In contrast, vitrified MII oocytes showed no capacity for blastocyst development after IVF or PA and vitrified GV oocytes were able to develop to blastocysts only after PA, but not after IVF. In conclusion, oocyte vitrification by the Cryotop method reduced the capacity for embryo development. Vitrification of GV oocytes, however, did not influence the capacity of meiotic nuclear maturation and they exhibited higher viability following vitrification at the MII stage.


2005 ◽  
Vol 17 (2) ◽  
pp. 219 ◽  
Author(s):  
C.E. Ferguson ◽  
T.R. Davidson ◽  
M.R.B. Mello ◽  
A.S. Lima ◽  
D.J. Kesler ◽  
...  

There has been much debate over a direct role for progesterone (P4) in early bovine embryo development. While previous attempts to supplement bovine embryos in vitro with P4 produced results that vary and are often contradictory, this may be a response of administering P4 at inappropriate times. Therefore, the objective of these experiments was to determine if P4 could exert a direct effect on developing IVF-derived bovine embryos when administered at an appropriate time of embryo development. In Exp. I, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 168); (2) vehicle, CR1aa + ETOH (0.01%) (n = 170); and (3) P4, CR1aa + ETOH + P4 (20 ng/mL in 50-μL droplet) (n = 173). In Exp. II, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 160); (2) vehicle, CR1aa + DMSO (0.01%) (n = 180); and (3) P4, CR1aa + DMSO (0.01%) + P4 (20 ng/mL in 50-μL droplet) (n = 170). All embryos were evaluated on Days 6 to 9 post-insemination and rates calculated from 8-cell embryos. In Exp. I, ETOH tended to have a detrimental effect with significantly fewer (P < 0.05) embryos (53%) developing to the blastocyst stage on Day 7 compared with the control (62%) and P4 (71%) groups. At Day 7, significantly more embryos cultured in P4 (71%) developed to the blastocyst stage compared with the control group (62%). P4 treatment significantly increased the number of Grade 1 blastocysts (25%) on Day 7 compared with vehicle (15%) and control (17%) groups. At the end of culture, there were also significantly more Day 9 hatched blastocysts in the P4 group (33%) compared with vehicle (22%) and control (21%) groups. Supplementing P4 in the culture medium increased the rate of development, resulting in significantly more blastocysts (8%) on Day 6 and hatched blastocysts (21%) on Day 8 compared with vehicle (3% and 12%) and control (0% and 8%) groups, respectively. In Exp. II, there were no significant differences between treatment groups for Day 7 blastocysts (control 54%, DMSO 61%, P4 57%) and Day 9 hatched blastocysts (control 46%, DMSO 51%, P4 46%). However, there were significantly more Grade 1 blastocysts in the P4 group (22% and 36%) on Days 6 and 8 compared with vehicle (11% and 23%) and control (13% and 23%) groups, respectively. The lack of improvement in Day 7 blastocysts and Day 9 hatched blastocysts rates leads to further uncertainty in understanding the P4 vehicle interactions. In conclusion, the results of these two experiments indicate that P4 can exert a direct effect on the developing IVF-derived bovine embryo; however, due to P4 vehicle interactions; other inert vehicles need to be explored to further evaluate the direct effects of P4 on the developing bovine embryo.


2004 ◽  
Vol 9 (1) ◽  
Author(s):  
M.G.L. PINTO ◽  
M.I.B. RUBIN ◽  
C.A.M. SILVA ◽  
T.F. HILGERT ◽  
M.F. SÁ FILHO ◽  
...  

O desenvolvimento embrionário de oócitos bovinos maturados in vitro (MIV) foi avaliado em meio suplementado com líquido folicular eqüino (Lfe). Foram distribuídos 1045 oócitos em 11 repetições formando três grupos tratamentos (T1, T2, T3) e um controle (C). O meio de maturação utilizado foi o TCM-199 acrescido de piruvato de sódio, hormônio folículo estimulante recombinante (rFSHh) e hormônio luteinizante equino (LHe). Suplementou-se esse meio com 10% de soro de égua em estro para o grupo controle e para T1, T2 e T3, o meio foi suplementado com 5, 10, e 20% de LFe, respectivamente. Os oócitos foram maturados in vitro (MIV) por 24h. A fecundação in vitro (FIV) foi realizada em meio Talp-Fert. A MIV e a FIV foram realizadas em estufa a 39ºC com 5% de CO2 em ar e umidade saturada. Os zigotos foram cultivados em meio SOFaaci, sob óleo mineral no interior de bolsas plásticas gaseificadas. As taxas de clivagem e de blastocistos foram observadas diariamente (D), e em D7, foram superiores (P0,05) às do grupo controle. Em D9, a taxa de blastocistos do T2 foi superior (P0,05). O LFe, na concentração de 10% pode ser utilizado, em substituição ao soro de égua em estro para suplementar o meio de MIV de oócitos bovinos. Equine follicular fluid on in vitro maturation of bovine oocytes Abstract Embryo development of bovine oocytes was evaluated using maturation medium supplemented with equine follicular fluid (eFF). One thousand and forty five (1045) oocytes were distributed in 11 replications forming three treatment groups (T1, T2 e T3) and one Control (C). TCM-199 added with sodium pyruvate, rFSHh and LHe was used as maturation medium. This medium was supplemented with 10% estrous mare serum for Control group, and 5, 10, and 20% eFF, respectively, for T1, T2 e T3 groups. In vitro maturation (IVM) of all groups was performed during 24h. In vitro fertilization (IVF) was performed in TALP-FERT medium. IVM and IVF were carried out in an incubator at 39ºC with 5% CO2 in air and saturated humidity. Zygotes were cultured in SOFaaci medium, under mineral oil in gasified bags. Cleavage and blastocyst rates were daily observed (D), and at D7, were higher (P0.05) for those from control group. At D9, blastocyst rate of T2 was higher (P0.05). The eFF, at a 10% concentration, can replace the use of estrous mare serum to supplement the IVM medium of bovine oocytes.


2016 ◽  
Vol 28 (2) ◽  
pp. 210
Author(s):  
P. Hugon ◽  
J. Lamy ◽  
E. Corbin ◽  
P. Mermillod ◽  
M. Saint-Dizier

This study was designed to evaluate the effects of oviductal fluid at different periovulatory times on oocyte maturation, modification of the zona pellucida (ZP), fertilization and embryo development. Bovine oviducts were collected at a slaughterhouse and classified as preovulatory (pre-ov: 1 pre-ov follicle and a regressing corpus luteum) or post-ovulatory (post-ov: a corpus haemorrhagicum or recent corpus luteum; n = 10 cows/stage). Both oviducts were flushed with 1 mL of sterile TCM-199, and oviductal flushes (OF) were aliquoted and stored at –80°C. Abattoir-derived bovine ovaries were aspirated and cumulus‐oocyte complexes (COC) with at least 3 cumulus layers and homogeneous oocyte cytoplasm were in vitro matured for 22 h in standard maturation medium (control group, n = 319) or in standard medium with 2× concentrated additives supplemented (50% v/v) with pre-ov OF (n = 255) or post-ov OF (n = 248). After in vitro maturation (IVM), subgroups of COC were denuded, and the time of digestion of the ZP by pronase 0.1% (v/v in TCM-199) was determined to evaluate ZP hardening. After IVM, COC were fertilised in vitro for 18–20 h at a final concentration of 1.106 million spermatozoa (spz)/mL. After in vitro fertilization (IVF), COC were denuded, washed twice and cultured for 8 days more under standard conditions. After IVM, IVF, and embryo culture, oocytes/embryos were fixed with ethanol, stained with Hoescht, and examined under fluorescence microscopy for determination of (1) maturation and developmental stages, (2) numbers of fertilised and polyspermic oocytes, and (3) spz bound to the ZP. Percentages were compared between groups by chi-square. Times of ZP digestion were compared by Kruskal‐Wallis test. Numbers of spz bound to the ZP were compared by ANOVA on normalised data followed by Newman-Keuls tests. Data are presented as mean ± SEM. A P < 0.05 was considered significant. Addition of OF during IVM had no effect on maturation rates compared with the control. However, the digestion time of the ZP by pronase was reduced after IVM with pre-ov OF (313 ± 21 s; n = 26) compared with post-ov OF (459 ± 23 s; n = 23) but not with the control (416 ± 30 s; n = 25). After IVF, the number of spermatozoa bound to the ZP was increased after IVM with pre-ov OF (57 ± 5 spz/oocyte; n = 67) and decreased after IVM with post-ov OF (34 ± 3 spz/oocyte; n = 76) compared with the control (42 ± 5 spz/oocyte; n = 60). Addition of OF during IVM had no effect on rates of IVF and polyspermia. However, the rate of development to the blastocyst stage was less after IVM with post-ov OF (10%, n = 97 cleaved oocytes) compared with control (24%, n = 130) and pre-ov OF (29%, n = 101). In conclusion, the OF collected before ovulation decreased the resistance of the ZP to protease digestion and increased its ability to bind spz, whereas it was the opposite for the post-ov OF. Furthermore, the post-ov OF decreased the developmental competence of fertilised oocytes.


2011 ◽  
Vol 23 (1) ◽  
pp. 107 ◽  
Author(s):  
B. K. Bauer ◽  
L. D. Spate ◽  
C. N. Murphy ◽  
R. S. Prather

In vitro culture systems are suboptimal as compared to in vivo. Previous next-generation sequencing analysis of in vivo fertilized and in vitro cultured (IVC) or in vivo cultured (IVV) porcine blastocyst stage embryos identified an arginine transporter (SLC7A1) expressed 63 fold higher in IVC compared to IVV blastocysts (Bauer et al. 2010 Biol. Reprod. Epub ahead of print). Arginine catabolism may play important roles in placental and conceptus growth and development as it is a substrate for synthesis of nitric oxide synthase and polyamines. The objective of this study was to determine the effects arginine had on both embryo development and mRNA expression in in vitro fertilized embryos. Cumulus–oocyte complexes were matured for 44 h in M199 supplemented with EGF, FSH, and LH. Oocytes with a visible polar body (metaphase II) were selected and fertilized in modified Tris Buffered Medium for 5 h and then placed into one of 5 treatment groups (Porcine Zygote Medium 3 (PZM3) with 0 mM, 0.12 mM (current concentration of arginine in PZM3), 0.36 mM, 0.72 mM, or 1.69 mM arginine). Twenty-eight hours post-fertilization, cleaved embryos were selected and moved into 25 μL drops of respective culture media and cultured to day 6 in 5% CO2, 5% O2, 90% N2 at 38.5°C. To determine the effect arginine had on development the percent of embryos that made it to the blastocyst stage for each treatment group were analysed using PROC GLM in SAS (SAS Institute, Cary, NC). A least significant difference post test comparison was completed to determine if significant differences existed between treatment groups (a,b,cP < 0.05). The percentage of cleaved embryos on Day 6 that developed to blastocyst was 57.2%b,c, 50.2%c, 67.3%a,b, 67.3%a,b, 70.4%a (N = 147, 163, 150, 120, and 134) in 0 mM, 0.12 mM, 0.36 mM, 0.72 mM, and 1.69 mM arginine, respectively. Real-time PCR was then completed to assess the affect arginine supplementation had on SLC7A1 mRNA expression. Three biological replicates, each containing 10 blastocyst pools to ensure enough starting material, were collected for each treatment group. RNA was isolated from each sample and 5 μL was linearly amplified (NuGEN Ovation Pico WTA System) so multiple genes could be compared and then purified using Bio-Rad MicroSpin Columns. Expression levels were calculated relative to the reference sample and the housekeeping gene, YWHAG. The ΔΔCT values were log-transformed and analysed using PROC GLM in SAS. The expression of SLC7A1 mRNA was decreased (P = 0.0006) compared to PZM3 in the 1.69 mM arginine group. These results illustrate the positive effects that additional arginine may be having on porcine embryo development during culture from the 2-cell to the blastocyst stage. Supplementing arginine to a final concentration of 1.69 mM during culture increases development of porcine embryos to blastocyst compared to PZM3 and also decreases the expression of SLC7A1. Evaluation of the transcriptional profile appears to be a good method of letting the embryo tell us what it needs for development, and in this case arginine. Funded by F21C.


2005 ◽  
Vol 17 (9) ◽  
pp. 91
Author(s):  
K. M. Banwell ◽  
M. Lane ◽  
D. L. Russell ◽  
K. L. Kind ◽  
J. G. Thompson

Follicular antral oxygen tension is thought to influence subsequent oocyte developmental competence. Despite this, in vitro maturation (IVM) is routinely performed in either 5 or 20% O2 and while low O2 has been shown to be beneficial to embryo development in many species, the effect of altering O2 concentration during IVM has not been adequately investigated. Here we investigated the effects of a range of O2 concentrations during IVM on meiotic maturation and subsequent embryo development after IVF. Ovaries from eCG-stimulated CBA F1 female mice (21 days) were collected and intact cumulus oocyte complexes (COCs) cultured for 17–18 h under 2, 5, 10 or 20% O2 (6% CO2 and balance of N2). Matured COCs were denuded of cumulus cells, fixed and stained (1% aceto-orcein) for visualisation of maturation status. No significant difference in maturation rates between treatment groups was observed. Following IVF (performed under 5% O2, 6% CO2 and balance of N2), no difference in fertilisation rates between treatment groups was observed in a randomly selected cohort 7 h post-fertilisation. There was also no significant difference in cleavage rates after 24 h or ability to reach blastocyst stage after 96 h, with a tendency (P = 0.079) for more blastocysts in 2% O2. However there was a significant increase in the number of trophectoderm cells present in the resulting blastocysts (P < 0.05) in the 2% O2 group (35 ± 2.1) compared to 20% O2 (25 ± 2.8). Our data suggests that O2 concentration during IVM does not influence nuclear maturation or subsequent fertilisation, cleavage and blastocyst development rates. However, maturation in 2% O2 significantly alters subsequent cell lineage within blastocysts to favour trophectoderm development. Such skewed trophectoderm cell number may influence embryo viability. Funded by NHMRC and NIH.


2017 ◽  
Vol 65 (4) ◽  
pp. 546-555
Author(s):  
Tayita Suttirojpattana ◽  
Tamás Somfai ◽  
Satoko Matoba ◽  
Takashi Nagai ◽  
Rangsun Parnpai ◽  
...  

This study determined the optimum storage vessel and the effects of resveratrol for the storage of in vitro matured (IVM) bovine oocytes. After IVM, the oocytes were kept in a Hepes-buffered medium at 25 °C for 20 h in different containers including Eppendorf tubes (ET) made of polypropylene (PP) and polystyrene (PS), and tissue culture tubes (TCT) made of PP, PS, and glass. Then oocytes were subjected to IVF and subsequent in vitro embryo development was compared among the groups and to that of a control group without storage. The percentage of blastocyst development in the control group was significantly higher than in the stored groups (P < 0.05). Among oocytes stored in TCT, the percentage of blastocyst development of oocytes stored in glass TCT was significantly higher than that of oocytes stored in PP and PS TCT (P < 0.05); however, it did not differ from that of oocytes stored in ET. The quality of blastocysts did not differ among the control and stored groups. Embryo development was not affected when 0.1, 1 or 10 μM resveratrol was added to the medium during oocyte storage. In conclusion, glass tubes were optimal for oocyte storage and resveratrol did not improve the development of stored oocytes.


2006 ◽  
Vol 18 (2) ◽  
pp. 272
Author(s):  
K. Kananen-Anttila ◽  
M. Eronen ◽  
J. Matilainen ◽  
M. Kallio ◽  
J. Peippo ◽  
...  

We have studied the effect of suppressed IVM on the developmental competence of bovine oocytes, aiming at elucidating the importance of cytoplasmic maturation in fertilization and embryo development. Six replicates of abattoir-derived oocytes were randomly divided into three IVM groups. Control (n = 950): TCM-199 with glutamax-I (Gibco, Grand Island, NY, USA), 0.25 mM Na-pyruvate, 100 IU mL−1 penicillin and 100 μg mL−1 streptomycin, 50 ng mL−1 FSH, and 10% fetal bovine serum (FBS) (Gibco); Serum+FSH-free (n = 944): same as control but without FSH and FBS; α-amanitin (n = 977): same as control but with 10 μg mL−1 α-amanitin. Nuclear maturation of oocytes was studied 24 h after the onset of IVM, the formation of sperm aster structure 10 hours post-insemination (hpi) and the formation of pronuclei 20 hpi. Sperm aster was visualized with β-tubulin antibody (modified from Navara et al. 1999 Dev. Biol. 162, 29–40). Presumptive zygotes were cultured until Day 7 in modified SOFaaci + 4 mg mL−1 fatty acid-free BSA in 5% O2. Cumulus cell expansion was seen only in the control group. The results of nuclear maturation, fertilization, and embryo development are summarized in Table 1. Serum and FSH deprivation did not have a statistically significant effect on the parameters studied (vs. control). α-amanitin exposure during IVM reduced nuclear maturation, fertilization, and Day 3 embryo cleavage vs. control, and resulted in total blockage of Day 7 blastocyst development. The treatment groups had significantly smaller mean diameters of male pronuclei (control: 14 ± 0.6 μ­m; serum+FSH-free: 12 ± 0.5 μ­m, P < 0.05; α-amanitin: 10 ± 0.6 μ­m, P < 0.001) and sperm asters (control: 86 ± 4 μ­m; serum+FSH-free: 82 ± 4 μ­m, P < 0.01; α-amanitin: 49 ± 7 μm, P < 0.001) (nonparametric Kruskall Wallis and Mann-Whitney U tests) vs. control group. Despite reduction in pronucleus and sperm aster diameter, serum and FSH deprivation during IVM did not affect in vitro developmental competence of bovine oocytes, suggesting a need for re-evaluation of the components of IVM. α-Amanitin exposure in IVM disturbed nuclear maturation, fertilization, and embryo development, indicating the essence of early transcription. Table 1. Average percentages ± (n) for nuclear maturation, fertilization (min two pronuclei), embryo cleavage, and blastocyst development


2007 ◽  
Vol 19 (1) ◽  
pp. 273 ◽  
Author(s):  
A. Sugulle ◽  
S. Katakawa ◽  
S. Yamamoto ◽  
S. Oomori ◽  
I. Itou ◽  
...  

The morphological identification of immature oocytes has commonly been used to select the bovine oocytes for IVF. However, &lt;30% of the recovered oocytes reach the blastocyst stage after fertilization, and this is probably due to the quality of the oocytes at the beginning of maturation. The brilliant cresyl blue (BCB) stain determines the activity of glucose-6-phosphate dehydrogenase, an enzyme synthesized in growing oocytes. The aim of this study was to evaluate the effect of the BCB stain on the selection of bovine oocytes and on the subsequent embryo development for in vitro production (IVP). Cumulus–oocyte complexes (COCs) were collected by the aspiration of 2- to 6-mm follicles. A total of 559 oocytes were divided into 2 groups: (1) a control group, immediately cultured, and (2) a BCB-incubated group. After 90 min of BCB staining (Pujol et al. 2004 Theriogenology 61, 735–744), the oocytes were divided into oocytes with blue cytoplasm (BCB+) and oocytes without blue cytoplasm (BCB−). The COCs were matured for 20 h in TCM-199 supplemented with 5% calf serum (CS) and 0.02 mg mL−1 FSH at 38.5°C under an atmosphere of 5% CO2 in air. The matured COCs were inseminated with 5 × 106 sperm mL−1. After 18 h of gamete co-culture, the presumed zygotes were cultured in CR1aa supplemented with 5% CS for 9 days at 38.5°C under an atmosphere of 5% CO2, 5% O2, and 90% N2. Embryonic development was evaluated at 48 h after IVF (proportion of ≥5-cell stage, the total cleavage rates) and on Days 7 to 9 (blastocyst rate). The experiment was replicated 5 times, and the data were analyzed by a chi-square test and ANOVA. The results are presented in Table 1. The proportion of embryos with ≥5-cell stage was significantly higher (P &lt; 0.01) in the BCB+ group than in the BCB− group, but not in the control group. The total cleavage rate for the BCB+ embryos was significantly higher than that of either the BCB− or the control group (P &lt; 0.01). There were also significant differences (P &lt; 0.01) in the blastocyst development between the BCB+ and BCB− embryos and between the BCB− and the control embryos (P &lt; 0.05). This result showed that the selection of bovine oocytes by BCB staining before in vitro maturation may be useful for selecting oocytes that are developmentally competent up to Day 9 for IVP. Table 1.Effect of selection of oocytes by brilliant cresyl blue (BCB) staining on the subsequent embryo development of in vitro-matured/in vitro-fertilized bovine embryos


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