Metabolism and cell allocation during parthenogenetic preimplantation mouse development

Crucial surviving aspects for vitrified in vitro-produced bovine embryos

“…In this study, the majority of apoptosis in fresh blastocysts occurred in the inner cell mass (ICM), when compared with the trophoblast (Fig. 2a), on the very same fashion that was described in both murine (Hardy & Handyside, 1996) and bovine (Byrne et al, 1999) …”

“…In this study, the majority of apoptosis in fresh blastocysts occurred in the inner cell mass (ICM), when compared with the trophoblast (Fig. 2 a ), on the very same fashion that was described in both murine (Hardy & Handyside, 1996) and bovine (Byrne et al ., 1999) embryos. The higher incidence of apoptosis in ICM might be explained by the removal of damaged or excessive cells, which are not needed or competent for the embryo development.…”

Cell death in the mammalian blastocyst

“…However, as Ͻ30% of the cells in the blastocyst contribute to the ICM, even a small number of dead cells in this lineage results in the observed dead cell index of 10-20%, compared with a much lower one of Ͻ3% in the TE. This confirms other studies where cell death was seen predominantly in the ICM (El-Shershaby and Hinchliffe, 1974;Copp, 1978;Mohr and Trounson, 1982;Handyside and Hunter, 1986;Hardy and Handyside, 1996), with lower levels detected in the TE (Copp, 1978;Hardy and Handyside, 1996;Brison and Schultz, 1997).…”

Consequences of In Vivo Development and Subsequent Culture on Apoptosis, Cell Number, and Blastocyst Formation in Bovine Embryos

“…The variable overestimation of the number of cells of the ICM did influence the ICM:TE ratio, but not the relation of the apoptotic indexes between the four groups. In all four groups, the apoptotic index of the ICM was significantly higher than that of the TE, which is in agreement with studies in bovine [19,42,43] and murine [18,44,45] embryos. It is assumed that apoptosis in the ICM may regulate this cell population, because the number of ICM cells reaches a plateau in later-stage blastocysts without decrease in mitotic division [46].…”