Influência da depleção e suplementação mitocondrial no processo de apoptose embrionária / Influence of mitochondrial depletion and suplementation in embryonic apoptosis

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

Studies developed with bovine zygotes submitted to a decrease of about 50% of the mitochondrial content did not present a deleterious effect on in vitro embryonic development. This model was developed by the centrifugation of zygotes after in vitro fertilization (IVF), removal of the mitochondria enriched cytoplast fraction (MECF) and posterior introduction of 20-30% ooplast (FERREIRA, 2006). Knowing that this biological model allows the development of embryos with mitochondrial depletion, the objective of this study was to evaluate the effect of the mitochondrial removal and supplementation in zygotes aiming to understand the organelle importance in the development and programmed cellular death process (PCD). Therefore, we developed a reconstruction model capable to generate mitochondrial depleted and supplemented embryos. The MECF of the centrifuged zygotes was removed from the donors oocyte (depleted group-D). To prepare the supplemented group (S), a biopsy of approximately 7.1% of the cytoplasm was removed from the recipient zygote for the supplementation with MECF derived from the donor. Mitochondrial depletion caused a decrease of DNAmt amount that was replenished before 72 hours possibly due to an increase of mtTFA, BCL2 and PI3K expression and no effects in Ψmm. The technique of mitochondrial supplementation by micromanipulation showed no effect on the mitochondria DNA amount and activity estimated by mitochondrial membrane potential (Ψmm). The Ψmm increased at 168ha in consequence of an increase in COXI and mtTFA expression. Mitochondrial depletion and supplementation caused a decrease in embryonic development in the 8-cells stage, on blastocyst production and total cell number. The supplementation resulted in increased rates of fragmented nuclei possibly due to an imbalance between pro- and anti-apoptotic factors.

ASSUNTO(S)

mitocôndria depletion zigotos apoptose apoptosis suplementação supplementation zygotes bovinos bovine depleção mitochondria

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