scholarly journals 127 LETHAL EFFECT OF HIGH CONCENTRATIONS OF PARECOXIB AND FLUNIXIN MEGLUMINE ON THE IN VITRO CULTURE OF BOVINE EMBRYOS

2009 ◽  
Vol 21 (1) ◽  
pp. 163 ◽  
Author(s):  
E. M. Razza ◽  
R. A. Satrapa ◽  
C. F. Silva ◽  
R. A. L. Simões ◽  
T. Nabhan ◽  
...  

The aim of this experiment was to evaluate the effects of cycloxigenase inhibitor drugs, i.e. flunixin meglumine (FM) and parecoxib (P), on the development of bovine embryos cultured in vitro until the blastocyst and hatched blastocyst stages. Immature oocytes were aspirated from slaughterhouse ovaries and morphologically selected for IVM (Monteiro FM et al. 2007 Anim. Reprod. 4, 51–58). Twenty hours after maturation (39°C and 5% CO2 in air), matured oocytes were transferred to fertilization media, inseminated with frozen–thawed semen, and incubated for 10 to 12 h. Presumptive zygotes (PZ) were then transferred to TCM 199 HEPES medium, vortexed to remove cumulus cells and finally to drops of IVC media (SOFaaci plus 5% BFS [Gibco] with 13 mm sodium pyruvate). Each drop of IVC medium had appropriate concentrations of FM (0.14/n = 123; 1.4/n = 122; 14/n = 117; 140/n = 44 or 1400 μg mL–1/n = 44 PZ) or P (0.09/n = 134; 0.9/n = 109; 9/n = 118; 90/n = 113 or 900 μg mL–1/n = 45 PZ), besides extra drops as control groups (CFM; n = 124 and CP; n = 149 PZ). Based on published data from bovine (FM) and human (P) administered concentrations, it was calculated the blood concentration to a bovine weighing 450 kg (FM = 14 and P = 9 μg mL–1). Both drugs were used from available commercial preparations, and in a pilot test, there were no deleterious effects of the solvent itself on the blastocyst and hatched blastocyst rates. During culture, petri dishes containing PZ/embryos were kept into plastic bags, under controlled atmosphere of 5% O2, 5% CO2 and 90% N2 at 39°C. There were 11 replicates for each treatment. In all drops (both drug concentrations and control group) the blastocyst and hatched blastocyst rates (BR and HBR, respectively) were evaluated at 144 and 192 h after fertilization, respectively. Statistical analysis was performed with ANOVA on ranks (Dunn’s test a posteriori and significance being considered when P < 0.05; BioEstat version 5.0). According to the results, FM (1400 and 140 μg mL–1) and P (900 μg mL–1) concentrations were toxic enough for a complete inhibition of in vitro bovine embryo development. There were no significant differences among the other drug concentrations and their respective control group, on the BR (27.7 ± 3.9; 29.6 ± 3.4 and 29.8% ± 4.8) and HBR (13.5 ± 4.4; 15.6 ± 3.8 and 22.1% ± 5.1), respectively to 0.14; 1.4 and 14 μg mL–1 for FM; on BR (26.0 ± 2.6; 18.2 ± 4.6; 25.8 ± 5.9 and 23.2% ± 4.8) and HBR (14.1 ± 3.3; 10.2 ± 3.3; 16.8 ± 3.8 and 12.0% ± 3.4), respectively to 0.09; 0.9; 9 and 90 μg mL–1 for P; and on BR (35.3 ± 5.2 and 36.5% ± 3.4) and HBR (26.6 ± 4.5 and 19.8% ± 3.6), respectively for CFM and CP. The results suggest that, during in vitro bovine embryo culture, there was no significant toxicity of either drug, with exception of the complete lethal concentrations of 140 and 1400 μg mL–1 (flunixin meglumine) and 900 μg mL–1 (parecoxib) on blastocyst production. Supported by FAPESP – Brazil (MFGN 06/06491-2 and 07/07705-9; EMR 07/04284-2; RAS; CFS and RALS) and CAPES – Brazil.

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.


2014 ◽  
Vol 26 (1) ◽  
pp. 155
Author(s):  
L. Baldoceda ◽  
C. Vigneault ◽  
P. Blondin ◽  
C. Robert

Mitochondria play an important role during early mammalian embryo development through their diverse cellular functions, in particular creating balance between production of ATP by electron transport chain and oxidative stress. Embryonic mitochondria are inherited maternally and independently of the nuclear genome. They show limited activity during the early developmental stages before embryonic genome activation. It has been shown that in vitro culture (IVC) has an adverse effect on mitochondrial function in embryos. So far several attempts have been performed to improve and rescue the impaired mitochondria. It has been shown that vitamin K2 (a membrane-bound electron carrier, similar to ubiquinone) was used to rescue mitochondrial dysfunction and resulted in more efficient ATP production in eukaryotic cells (Vos et al. 2012 Science 336, 1306–1310). Therefore, the aim of the present study was to investigate the effects of supplementation of vitamin K2 on mitochondrial activity and blastocyst rate. Cumulus–oocytes complexes (n = 687) recovered from slaughtered animals, were matured and fertilized in vitro according to our standard procedures. After fertilization, zygotes were cultured in SOF media supplemented with 10 mg mL–1 BSA. At 96 h post-fertilization, vitamin K2 was added to the culture media (n = 448 oocytes). On Day 7, treatment embryos were compared with untreated controls (n = 239 oocytes). In vitro culture was carried out at 38.5°C under 5% CO2, 7% O2, and 88% N2. Differences among groups in blastocyst yield were analysed by ANOVA. Mitochondrial activity data was analysed by unpaired 2-tailed t-tests. Results show that the vitamin K2-treated group had a significantly (P < 0.05) higher blastocyst rate (+8.6%), expanded blastocyst rate (+7.8%), as well as better morphological quality compared with the control group. Furthermore, to evaluate mitochondria activity, pools of embryos of each treatment were labelled with a specific dye for active mitochondria (Mitotracker Red). A significantly higher intensity of Mitotracker Red (P < 0.05) was observed in the vitamin K2 treatment versus control group, as measured by fluorescent microscopy. In conclusion, for the first time, our data prove that supplementation of vitamin K2 during IVC of bovine embryos increases blastocyst rates and embryo quality. Future studies will focus on gene expression to identify targets implicated in impaired mitochondrial activity in in vitro bovine embryo production.


2021 ◽  
Author(s):  
Aimé Jazmín Garza Arredondo ◽  
Diana Elisa Zamora Ávila ◽  
Uziel Castillo Velásquez ◽  
Gustavo Moreno Degollado ◽  
José Fernando De La Torre Sánchez ◽  
...  

Abstract Endogenous heat shock cognate 71 kDa protein (HSC70) has a vital role in early embryonic development. This study assessed the effects of exogenous HSC70 on bovine embryo development and expression of genes associated with apoptosis. Expression analyses of HSPA1A, HSPA8, Bcl-2, and Bax genes were performed in bovine embryos in vivo on day 7 of development. Subsequently, expression of HSPA1A and HSPA8 were associated with apoptotic genes (Bcl-2 and Bax) in cultured bovine embryos in vitro that were supplemented with various concentrations (0 or control group, 50, and 100 ng) of HSC70. The results indicated that the control group (0 ng) in vitro embryos had higher expression of HSPA8, Bax, and Bcl-2 genes, compared with the vivo embryos (P < 0.01). In vitro-produced embryos supplemented with 50 ng or 100 ng HSC70 had higher expression of HSPA1A, HSC70, Bcl-2, and Bax genes, compared with the control group (P < 0.01). Embryos supplemented with 100 ng had greater expression of the HSPA8 gene compared with the control group and the group supplemented with 50 ng. However, embryos supplemented with 50 ng had better characteristics (i.e., stage of development and quality) than the control and 100-ng groups. In conclusion, supplementation of in vitro culture medium with HSC70 promoted development to the blastocyst stage and improved blastocyst quality.


2016 ◽  
Vol 28 (2) ◽  
pp. 186
Author(s):  
F. Fieni ◽  
M. Oseikria ◽  
K. Laroucau ◽  
F. Vorimore ◽  
D. Tainturier ◽  
...  

Chlamydia abortus (C. abortus) in cattle has been reported sporadically throughout the world and is implicated in respiratory, ocular, and reproductive disease as abortion, infertility, chronic mastitis, vaginal discharge, and endometritis. In addition, C. abortus presents a zoonotic risk exposure of pregnant women to infected animal and can lead to severe septicaemia in the mother, resulting in spontaneous abortion or stillbirth of the fetus. To investigate the risk of C. abortus transmission via bovine embryo transfer, our study aims to determine whether the embryonic ZP of in vitro-produced embryos protects early embryo cells against C. abortus infection and whether the bacteria adhere to or infect the cells of early bovine embryos (ZP-free) after in vitro infection. We also evaluated the efficacy of the washing procedure recommended by the IETS to decontaminate bovine embryos exposed to C. abortus in vitro. Ninety (8 to 16 cells) bovine embryos, produced in vitro, were randomly divided into 10 batches. Eight batches (4 ZP-intact and 4 ZP-free) of 10 embryos were incubated in a medium containing 4.8 × 107 Chlamydia/mL of AB7 strain (ANSES, Maisons-Alfort, France). After incubation for 18 h at 37°C in an atmosphere of 5% CO2, the embryos were washed in batches in 10 successive baths of a PBS and 5% FCS solution without trypsin nor antibiotics in accordance with IETS guidelines. In parallel, 2 batches of 5 embryos (1 ZP-intact and 1 ZP-free) were subjected to similar procedures but without exposure to C. abortus as a control group. The 10 washing fluids from each batch were collected and centrifuged for 1 h at 13 000 × g. The embryos and wash pellets were tested using RT-PCR. Chlamydia abortus DNA was found in all ZP-intact and ZP-free infected embryos after 10 successive washes. It was also detected in the tenth wash fluid for 1 batch (1/4) of ZP-intact infected embryos and in 3 batches (3/4) of ZP-free infected embryos. In contrast, none of the embryos or their washing fluids in the control batches was DNA positive. These results demonstrate that C. abortus adheres to or penetrates the ZP as well as the early embryonic cells of in vitro-produced bovine embryos after in vitro infection, and that the standard washing protocol recommended by the IETS failed to remove it. The persistence of these bacteria after washing makes the embryo a potential means of transmission of the bacterium during embryo transfer from infected donor cows to healthy recipients or their offspring. Nevertheless, the finding of C. abortus DNA by RT-PCR did not imply that the bacteria found is still infective. Further studies are required to investigate whether enzymatic or antibiotic treatment of bovine embryos infected by C. abortus would eliminate the bacteria from the ZP.


2014 ◽  
Vol 26 (1) ◽  
pp. 183
Author(s):  
M. Takehisa ◽  
S. Kondo ◽  
K. Imai ◽  
O. Dochi ◽  
H. Koyama

Mechanical vibration enhances the cytoplyasmic maturation of in vitro-matured (IVM) pig oocytes (Mizobe et al. 2010 J. Reprod. Dev. 56, 285–290), as well as the development of in vitro-cultured (IVC) bovine embryos (Fujita et al. 2010 Rakuno Gakuen University Graduation thesis,1–36). In this study, the effects of intervals of mechanical vibration during in vitro culture, after IVF, on the development of embryos derived from low-quality oocytes were examined. Cumulus-oocyte complexes (COC) were collected by aspiration of ovarian follicles (diameter = 2 to 6 mm) obtained from a local abattoir. In this experiment, only grade 3 oocytes (i.e. those with one layer or partially remaining cumulus cells and normal cytoplasm) were used. Groups of 20 COC were matured in 100-μL droplets of in vitro TCM-199 supplemented with 5% calf serum and 0.02 AU mL–1 of FSH at 38.5°C under an atmosphere of 5% CO2 in air for 20 h. Matured COC were inseminated with 5 × 106 sperms mL–1 for 18 h. After 18 h of gamete co-culture, the presumptive zygotes were cultured in CR1aa medium supplemented with 5% calf serum at 38.5°C under an atmosphere of 5% O2, 5% CO2, and 90% N2 for 9 days (fertilization = Day 0). Presumptive zygotes were cultured in vitro without mechanical vibration (control; n = 467) and with mechanical vibration for 5 s at 5 min (n = 180), 10 min (n = 180), 15 min (n = 180), and 60 min (n = 200) for 9 days. Embryo development was evaluated for cleavage and blastocyst rates, on Days 3 and 7 to 9 after IVF, respectively. The cleavage and blastocyst formation rates were analysed by the chi-squared test. Vibration at 15-min intervals increased (P < 0.05) cleavage rate compared to 5 min, 60 min, and control (control: 66.2 ± 22.1%; 5 min: 49.4 ± 10.2%; 10 min: 70.0 ± 7.7%; 15 min: 86.2 ± 6.6%; and 60 min: 64.0 ± 8.5%).The highest (P < 0.05) blastocyst rate among the experimental groups was found with 15-min intervals for vibration (control: 21.6 ± 9.2%; 5 min: 15.0 ± 5.3%; 10 min: 22.8 ± 1.8%; 60 min: 21.5 ± 5.0%). These results indicated that the cleavage and blastocyst formation rates of IVM-IVF-IVC bovine embryos derived from low-quality oocytes can be improved by physical stimulus during IVC. In addition, it was shown that 15-min intervals of mechanical vibration elicited the highest benefit for the development of embryos.


1996 ◽  
Vol 5 (5) ◽  
pp. 503-508 ◽  
Author(s):  
Kristiina Bredbacka ◽  
Peter Bredbacka

The effect of alanine (1 mM) and glycine (10 mM) supplementation on bovine embryo development in vitro was investigated. Presumptive bovine zygotes, produced by in vitro maturation and insemination of oocytes, were cultured for 144 h in CRlaa medium in the absence (Experiments 1 and 2) or presence of cumulus cells (Experiment 3). In Experiment I, the proportion of morulae and blastocysts of cleaved embryos in glycine-supplemented medium was not different from that of the control medium (34% in both media); however, the cell numbers of morulae and blastocysts were significantly higher in the glycine-enriched medium (69.5 vs. 53.3, P = 0.016). In Experiment 2, addition of alanine did not improve the formation of morulae and blastocysts (13% vs. 21% in control medium), and the mean cell numbers in morulae and blastocysts were lower than those in the control group (34.3 vs. 68.7, P = 0.007). In the presence of cumulus cells, the combined supplementation of glycine and alanine increased the proportion of morulae and blastocysts over that in the control medium (31% vs. 14%, P = 0.003).


Zygote ◽  
2001 ◽  
Vol 9 (3) ◽  
pp. 211-218 ◽  
Author(s):  
Jeong Tae Do ◽  
Kwon Ho Hong ◽  
Bo Yon Lee ◽  
Seung Bo Kim ◽  
Nam-Hyung Kim ◽  
...  

In this study we examined the developmental potential of reconstructed embryos and the fate of donor mitochondria during preimplantation development after nuclear transfer in cattle. Isolated cumulus cells were used as donor cells in nuclear transfer. Cumulus cells labelled with MitoTracker Green FM fluorochrome were injected into enucleated bovine MII oocytes and cultured in vitro. MitoTracker labelling on donor cells did not have a detrimental effect on blastocyst formation following nuclear transfer. Cleavage rate was about 69% (56/81) and blastocyst formation rate was 6.2% (5/81) at 7 days after nuclear transfer. The labelled mitochondria dispersed to the cytoplasm and became distributed between blastomeres and could be identified up to the 8- to 15-cell stage. Small patches of mitochondria were detected in some 8- to 15-cell stage embryos (5/20). However, donor mitochondria were not detected in embryos at the 16-cell stage and subsequent developmental stages. In the control group, mitochondria could be identified in arrested 1-cell embryos up to 7 days after nuclear transfer. These results suggest that disappearance of the labelled donor mitochondria in nuclear transfer bovine embryos is not due to fading of the fluorochrome marker, but is rather an as yet undefined cytoplasmic event.


2015 ◽  
Vol 27 (1) ◽  
pp. 202
Author(s):  
K. Saeki ◽  
Y. Fujiki

Bovine embryos are now routinely produced with oocytes collected from slaughterhouse ovaries or by transvaginal ovum pickup. The oocytes are matured, fertilized, and cultured in a water-jacketed CO2/O2 incubator. Gas phase in incubators is usually maintained at 5% CO2 in air for in vitro maturation (IVM) and IVF of oocytes and at 5% CO2, 5% O2, and 90% N2 for in vitro culture (IVC) of embryos. Here we investigated whether two chemical packets that regulate CO2 and O2 for culturing bacteria (Mitsubishi Gas Chemical, Tokyo, Japan) could be used to control the gas phase in vitro production (IVP) of cattle embryos. One packet (Anaero Pack-CO2) was maintained at a CO2 level of ~5% in a 2.5-L container and the other (Anaero Pack-MicroAnaero) was maintained at a CO2 level of 5–8% and an O2 level of 6 to 12%. Bovine cumulus-oocyte complexes (COC, n = 970) were collected from slaughterhouse ovaries, matured in HEPES-buffered TCM-199 (catalog number 12340–030, Invitrogen) supplemented with 10% FCS, 0.02 Armour unit mL–1 FSH and 1 µg mL–1 E2 for 22 h, and fertilized in medium IVF100 [Research Institute for the Functional Peptides Co. Ltd. (IFP), Yamagata, Japan] with frozen-thawed sperm (4 × 106 cells mL–1) for 6 h. Sperm and cumulus cells were removed from the oocytes. The denuded oocytes were cultured in IVD101 (IFP, 20 to 30 embryos/50 μL) for 8 days (Day 0 = IVF). Culture was carried out at 39°C with maximum humidity. Five different combinations of gas conditions were used for incubation (Table 1). Experiments were repeated 3 times. Cleavage and blastocyst rates were assessed on Day 8. Data were analysed by ANOVA followed by Fisher's PLSD test. In the five conditions, rates of matured oocytes (oocytes at MII, n = 210) were 70 to 73% and rates of normal fertilized oocytes (oocytes with 2 pronuclei, n = 310) were 67 to 75%. Cleavage rates of embryos after 8 days of culture (n = 450) were 68 to 75%, and rates of blastocysts from cleaved embryos were 25 to 40%. None of the above measures were significantly different among the 5 conditions (P > 0.05). These results indicate that gas phase control is not needed for IVM and IVF of bovine oocytes for their subsequent development. Anaero Pack-MicroAnaero (5–8% CO2, 6–12% O2) can be used for IVC of bovine embryos. The CO2-generating and deoxidizing packets can be successfully used to control the gas phase during bovine embryo production. Table 1.Five different combinations of gas conditions used for incubation


2008 ◽  
Vol 20 (1) ◽  
pp. 184
Author(s):  
K. J. Mattson ◽  
B. R. Devlin ◽  
N. M. Loskutoff

According to the Manual of the International Embryo Transfer Society, trypsin can be used to remove certain pathogenic agents from in vivo-derived embryos. Research is currently in progress to determine whether trypsin can also remove pathogenic agents from semen. The original research on embryos involved the use of trypsin from pig pancreatic extracts. Because of stricter guidelines from international regulatory agencies on the use of animal products, several recombinant serine protease products are now becoming available. TrypZean (Sigma, St. Louis, MO, USA) is a recombinant developed from corn and is the first bovine sequence recombinant trypsin to contain no animal by-products. As part of our ongoing research on the effects of trypsin on sperm, the goal of this investigation was to examine the development of bovine embryos produced from sperm treated with the recombinant TrypZean compared with pig pancreas trypsin (Sigma) and a control (no trypsin). Oocyte aspiration, maturation, fertilization, and embryo culture were performed using standard methods in 9 replications. Semen was collected and pooled from Bos taurus and frozen in an egg-yolk cryodiluent (Biladyl, Minitube, Verona, WI). The semen was processed using density gradient centrifugation composed of 1 mL of 30% Percoll (Sigma), layered over 2 mL of 45% Percoll containing either 0.25% TrypZean (n = 972 oocytes), 0.25% trypsin (n = 1040 oocytes), or no trypsin for the control group (n = 1024 oocytes). The bottom layer for the 2 treatments and control was 2 mL of 90% Percoll containing 10 µg mL–1 of soy-based protease inhibitor (Sigma). The density gradients were centrifuged at 700g for 30 min, after which time the pellets were washed in 5 mL of prewarmed TL HEPES Solution (Cambrex) and centrifuged at 300g for 10 min. The resulting sperm pellets were then resuspended in a volume calculated to provide 1 � 106 sperm mL–1 for in vitro insemination. The results were compared using one-way ANOVA. There were no statistically significant differences (P > 0.05) between any of the measures of embryonic development for the control and either of the treatment groups. Cleavage rates were measured for TrypZean (n = 689, 70.9%), trypsin (n = 729, 70.1%), and the control (n = 757, 73.9%) groups. More embryos reached the morula to blastocyst stages with the TrypZean (n = 367, 53.3%) and trypsin (n = 389, 53.4%) groups than the control (n = 369, 48.7%) group; however, these differences also were not statistically significant (P = 0.91) because of the large variation within the groups. In conclusion, the TrypZean and pig pancreas trypsin treatments of sperm prior to insemination showed no detrimental effects on IVF-derived bovine embryo development.


2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 2-3
Author(s):  
Theisy P Acosta Pérez

Abstract α-tocopherol is known to be a powerful antioxidant, in this regard, it was added to bovine oocyte in vitro maturation media to evaluate its effect on oocyte maturation. Oocytes (n = 624) aspirated from ovaries of slaughtered cows were classified by quality and divided in four categories according to cytoplasm appearance and cumulus cells layers. Oocytes were washed in TCM-199 supplemented with fetal bovine serum (FBS) and FSH, then distributed in maturation media (TCM-199 supplemented with FBS, FSH and gentamicin). Three experimental groups of α-tocopherol (50, 100 and 200 mM) and a control group without α-tocopherol were used. Maturation was carried 22 h at 38.5°C in a 5% CO2 atmosphere. Oocytes were examined to determine cumulus expansion as categorical data (expansion or no expansion), as well as cumulus expansion Index (CEI). For CEI determination oocytes were graded 0 to 4, being 0 those with null expansion and 4 those with a noticeable cell expansion, then the number of oocytes were multiplied by the grade given and a sum of the totals was obtained, the new total was divided by the total of oocytes in the group and the result obtained corresponded to the CEI of the group. Results were analyzed with Chi Square test (for maturation rates) and an ANOVA (for the CEI) using the SAS system, data are presented as mean ± standard error. There was no statistical difference between control and α-tocopherol groups (P &gt;0.05). Numerically, the control group showed a higher maturation rate (100%) and obtained a higher CEI (2.44±0.20), followed by the 50 mM group (98.16%; 2.39±0.13), the groups 200 mM (97.40%; 2.00±0.14) and 100 mM (96.25%; 2.06±0.24) were the lowest. The addition of the minimum concentration (50 mM) of α-tocopherol to the maturation media could improve maturation rates without exposing oocytes to toxic effects.


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