In vitro maturation, apoptotic gene expression and incidence of numerical chromosomal abnormalities following cryotop vitrification of sheep cumulus-oocyte complexes

Ebrahimi, Bita; Valojerdi, Mojtaba Rezazadeh; Eftekhari‐Yazdi, Poopak; Baharvand, Hossein

doi:10.1007/s10815-010-9401-z

Cited by 47 publications

(32 citation statements)

References 48 publications

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“…These results demonstrated that the use of this technique was not sufficient to activate the apoptotic process. However, induced numerical chromosomal abnormalities that reduced IVM rates was observed (Ebrahimi et al, 2010b). Succu et al (2007a) also reported chromosomal damages in 93% of oocytes vitrified with OPS, 83% with cryotop, and 63% with cryoloop when vitrified in the same concentration of cryoprotectants.…”

Section: Cryoprotectantsmentioning

confidence: 98%

“…Indeed some studies have demonstrated that the vitrification process in sheep oocytes caused damages on morphology, ultrastructure, meiotic spindle and chromosomal arrangement (Succu et al, 2007a;Ebrahimi et al, 2010b;Ebrahimi et al, 2012). These changes can be classified as either reversible or irreversible.…”

Section: Main Damages To Vitrified Oocytesmentioning

confidence: 99%

“…The objective of these techniques is to reduce the volume of solution and improve the contact with nitrogen to increase the cooling speed and allows the occurrence of vitrification of solution even with lower concentrations of CP (less toxic). However, some aspects still need to be clarified, as demonstrated by the few studies comparing different techniques in small ruminant oocytes (Ebrahimi et al, 2012;Rao et al, 2012).…”

Section: Cryoprotectantsmentioning

confidence: 99%

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Factors that affect oocyte vitrification in small ruminants

Chaves

Souza-Fabjan

Mermillod

et al. 2014

RBCV

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At the end of its growth, the mammalian oocyte, include in preovulatory follicle, is the largest cell of the organism, with about 120 µm in diameter. The size of oocyte, together with the specific arrangement of its organels and cytoskeleton, makes a real challenge for cryopreservation techniques. For such large cell, methods that do not require equilibrium to cryopreservation, such as vitrification, are more promising. It is important to highlight that the cryopreservation of oocytes is more difficult than zygotes or later stage embryos and this technique is a challenging task because of oocyte sensitive nature to chilling and toxic effects of cryoprotectants. However, the development of a reliable method for oocyte cryopreservation would be an important advance in the field of reproductive biology for the preservation of genetic resources. The vitrification of mammalian oocytes is influenced by many variables, such as different cryoprotectants, vitrification techniques, presence or absence of cumulus cells, the oocyte structure, metabolism (such as level of lipid storage) and meiotic stage. Thus, all these factors should be considered to optimize the techniques and adapt them to oocytes from each species. Therefore, the present review aims to describe the main factors that affect oocyte vitrification in sheep and goats, reporting the main findings in both species, as well as perspectives of future improvements.Keywords: COC, cryopreservation, gamete, goat, sheep. ResumoNo fim do seu crescimento, o oócito mamífero é a maior célula do organismo, com cerca de 120 µm de diâmetro. O tamanho do oócito em conjunto com a disposição específica das organelas e do citoesqueleto faz com que ele represente um verdadeiro desafio para as técnicas de criopreservação. Para grandes células, métodos que não exigem equilíbrio para criopreservação, como a vitrificação, são mais promissores. É importante ressaltar que a criopreservação de oócitos é mais difícil que de zigotos ou embriões em estádios mais tardios e esta técnica representa um desafio devido à natureza sensível do oócito ao resfriamento e aos efeitos tóxicos de crioprotetores. Entretanto, o desenvolvimento de uma técnica confiável para a criopreservação oocitária representaria um avanço importante para a preservação de recursos genéticos. A vitrificação de oócitos em mamíferos é influenciada por muitas variáveis , tais como diferentes crioprotetores, técnicas de vitrificação, presença ou ausência de células do cumulus, estrutura do oócito, metabolismo (como o nível de armazenamento de lipídios) e estágio meiótico. Assim, todos esses fatores devem ser considerados quando o objetivo é otimizar as técnicas e adaptá-las para oócitos de cada espécie. Assim, a presente revisão tem como objetivo descrever os principais fatores que afetam a vitrificação de oócitos em ovinos e caprinos, relatando os principais resultados em ambas as espécies, bem como as perspectivas de melhorias futuras.

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Section: Cryoprotectantsmentioning

confidence: 98%

Section: Main Damages To Vitrified Oocytesmentioning

confidence: 99%

Section: Cryoprotectantsmentioning

confidence: 99%

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Factors that affect oocyte vitrification in small ruminants

Chaves

Souza-Fabjan

Mermillod

et al. 2014

RBCV

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“…On the other hand, the DMSO mechanism of action may impair the ability of cumulus cells to expand during the cytoplasmic maturation process, probably without affecting the nuclear maturity of the oocytes (Cetin & Bastan, 2006;Ebrahimi et al, 2010;Hajarian et al, 2011). Accordingly, as our results showed, the nuclear maturity of the oocytes was not affected resulting in a comparable cleavage rate between DMSO-and PROH-treated groups even if the maturation rate was statistically different.…”

Section: Discussionmentioning

confidence: 45%

The effect of vitrification of immature bovine oocytes to the subsequentin vitrodevelopment and gene expression

Faheem

Baron

Carvalhais

et al. 2014

Zygote

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Immature 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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“…The activation of the Bcl-2, specifically the pro-apoptotic member genes is performed by the release of cytochrome C which interact with the apoptosis enzyme Apaf-1 and therefore activate caspase 9. The other activation of the anti-apoptotic member of the Bcl-2 gene is through the blocking apoptosis induced by the external stimulus (Ebrahimi et al, 2010) and when the the pro-apoptotic protein BAX is expressed it counteracts the apoptosis-preventing effect of BCL-2 (Somal et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

145 the Role of Cell Apoptosis on in Vitro-Produced Beef Cattle Embryos

Nkadimeng

2017

Reprod. Fertil. Dev.

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Successful in vitro development of embryos is dependent upon maintenance of cellular function in the embryonic microenvironment. Exposure of pre-implantation embryos to a variety of cellular stresses can induce apoptosis in all or a fraction of blastomeres. Among the conditions that can induce apoptosis in cattle embryo production in vitro are heat shock, media composition, oxygen levels, and tumour necrosis factor (TNF)-α. The aim of the study was therefore to evaluate the in vitro culture environment of embryos in terms of cell apoptosis through caspase and DNA fragmentation evaluation. A total of 1200 immature oocytes were collected at slaughter from indigenous South African cow ovaries. The cumulus-oocyte complexes were randomly allocated into 2 maturation temperatures, 39°C and 41°C (200/temperature /replicated 6 times), and cultured in M199 + FSH-LH-oestradiol medium under oil at 100% humidity and 5% CO2 for 24 h. Postmaturation, oocytes were subjected to normal subsequent embryo conditions (Rynkowska et al. 2011 Biotechnol. Comput. Biol. Bionanotechnol. 92, 45–53). All matured oocytes were fertilized for 6 h with frozen-thawed Nguni bull semen from 10 bulls replicated 5 times at a concentration of 265 × 106 sperm cells/mL in Bracket and Oliphant medium under oil. The presumptive zygotes from each treatment were cultured into SOF-BSA medium under oil and incubated at 39°C for assessment of cleavage rate post IVF. Produced embryos were divided into 3 groups: 2–4 cell, ≥8 cell embryos, and blastocyst. Two- to four-cell embryos were removed at Day 2, ≥8 cell at Day 5 (mainly 8-cell, morula, and cavitated blastocyst), and expanded blastocyst at Day 7 of embryo culture to determine caspase activity and DNA fragmentation for evidence of apoptosis. Caspase was performed using colourimetric assay on a 96-well microplate reader and monitored at 450 nm reference filter. The DNA fragmentation was examined using the TUNEL assay method and imaging was done using the Alexa Fluor® 488 emission at 519 nm. Data were analysed using SAS 9.2 software (SAS Institute Inc., Cary, NC, USA), and Shapiro-Wilks test was used on the standardized residuals to test for deviations from normality, means of significant effects were compared using Student’s t-l.s.d. at the 95% confidence interval. There was no significant difference on the cleavage rates [39°C (72.0 ± 22.70) and 41°C (67.2 ± 18.9)] and blastocysts [39°C (11.4 ± 2.6) and 41°C (11.2 ± 6.3)] from both maturation temperatures. Caspase activity showed no significant difference on 2–4 cell [39°C (0.015 ± 0.001) and 41°C (0.016 ± 0.002)] and ≥8 cell embryos at both temperatures [39°C (0.022 ± 0.007a) and 41°C (0.032 ± 0.013)]. However, blastocyst differed significantly at both temperatures [39°C (0.037 ± 0.012) and 41°C (0.053 ± 0.005)]. A higher (P < 0.05) DNA fragmentation was observed at 2–4 cell (6.5 ± 2.9), ≥8 cell (13.3 ± 3.1), and blastocyst (48.0 ± 8.2) for embryos produced from 41°C matured oocytes compared to the 39°C maturation group [2–4 cell (2.2 ± 1.2), ≥8 cell (4.5 ± 1.9), and blastocyst (9.7 ± 6.7)]. It is therefore concluded that embryos produced from 41°C matured oocytes can have the same developmental capacity as the 39°C maturation group. Moreover, both temperatures can show signs of apoptosis, however, with more apoptosis evidence in the 41°C than the 39°C maturation group.

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In vitro maturation, apoptotic gene expression and incidence of numerical chromosomal abnormalities following cryotop vitrification of sheep cumulus-oocyte complexes

Cited by 47 publications

References 48 publications

Factors that affect oocyte vitrification in small ruminants

Factors that affect oocyte vitrification in small ruminants

The effect of vitrification of immature bovine oocytes to the subsequentin vitrodevelopment and gene expression

145 the Role of Cell Apoptosis on in Vitro-Produced Beef Cattle Embryos

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