The effect of vitrification of immature bovine oocytes to the subsequent in vitro development and gene expression.
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.
['Faheem|Marwa S|MS|', 'Baron|E|E|', 'Carvalhais|I|I|', 'Chaveiro|A|A|', 'Pavani|K|K|', 'da Silva|F Moreira|FM|']
D000818:Animals D001755:Blastocyst D015820:Cadherins D002417:Cattle D018031:Connexin 43 D015925:Cryopreservation D003451:Cryoprotective Agents D004248:DNA (Cytosine-5-)-Methyltransferases D004121:Dimethyl Sulfoxide D019855:Ethylene Glycol D005260:Female D005307:Fertilization in Vitro D018507:Gene Expression Regulation, Developmental D018840:HSP70 Heat-Shock Proteins D008297:Male D009028:Morula D009865:Oocytes D019946:Propylene Glycol D058989:Vitrification
Cryotop Cryoprotectants Cryopreservation In vitro fertilization Real-time quantitative PCR