AffiliationUniversity of Birmingham
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AbstractThe mitochondrion is explicitly involved in cytoplasmic regulation and is the cell's major generator of ATP. Our aim was to determine whether mitochondria alone could influence fertilisation outcome. In vitro, oocyte competence can be assessed through the presence of glucose-6-phosphate dehydrogenase (G6PD) as indicated by the dye, brilliant cresyl blue (BCB). Using porcine in vitro fertilisation (IVF), we have assessed oocyte maturation, cytoplasmic volume, fertilisation outcome, mitochondrial number as determined by mtDNA copy number, and whether mitochondria are uniformly distributed between blastomeres of each embryo. After staining with BCB, we observed a significant difference in cytoplasmic volume between BCB positive (BCB+) and BCB negative (BCB-) oocytes. There was also a significant difference in mtDNA copy number between fertilised and unfertilised oocytes and unequal mitochondrial segregation between blastomeres during early cleavage stages. Furthermore, we have supplemented BCB- oocytes with mitochondria from maternal relatives and observed a significant difference in fertilisation outcomes following both IVF and intracytoplasmic sperm injection (ICSI) between supplemented, sham-injected and non-treated BCB- oocytes. We have therefore demonstrated a relationship between oocyte maturity, cytoplasmic volume, and fertilisation outcome and mitochondrial content. These data suggest that mitochondrial number is important for fertilisation outcome and embryonic development. Furthermore, a mitochondrial pre-fertilisation threshold may ensure that, as mitochondria are diluted out during post-fertilisation cleavage, there are sufficient copies of mtDNA per blastomere to allow transmission of mtDNA to each cell of the post-implantation embryo after the initiation of mtDNA replication during the early postimplantation stages.
CitationEl Shourbagy, S.H., Spikings, E.C., Freitas, M., St John, J.C. (2006) 'Mitochondria directly influence fertilisation outcome in the pig', Reproduction 131 (2):233-45
PublisherSociety for Reproduction and Fertility
The following license files are associated with this item:
- Meiotic progression, mitochondrial features and fertilisation characteristics of porcine oocytes with different G6PDH activities.
- Authors: Egerszegi I, Alm H, Rátky J, Heleil B, Brüssow KP, Torner H
- Issue date: 2010
- Regulated mitochondrial DNA replication during oocyte maturation is essential for successful porcine embryonic development.
- Authors: Spikings EC, Alderson J, St John JC
- Issue date: 2007 Feb
- Effect of oocyte quality on blastocyst development after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in a sheep model.
- Authors: Catalá MG, Izquierdo D, Rodríguez-Prado M, Hammami S, Paramio MT
- Issue date: 2012 Apr
- Selection of bovine oocytes by brilliant cresyl blue staining: effect on meiosis progression, organelle distribution and embryo development.
- Authors: Silva DS, Rodriguez P, Galuppo A, Arruda NS, Rodrigues JL
- Issue date: 2013 Aug
- Developmental competence of porcine oocytes selected by brilliant cresyl blue and matured individually in a chemically defined culture medium.
- Authors: Ishizaki C, Watanabe H, Bhuiyan MM, Fukui Y
- Issue date: 2009 Jul 1