Ultrastructure of preimplantation human embryos co-cultured with human ampullary cells

Ultrastructure of preimplantation genetic diagnosis-derived human blastocysts grown in a coculture system after vitrification

“…These organelles are elongated in shape and have defined transverse cristae with no electrodense material, and are usually located near microfilaments. We also detected lipidic droplets, ribosomes, Golgi complexes, and cisterns of rough endoplasmic reticulum, which were sometimes found to be dilated, as previously described (27)(28)(29)(30).…”

Development and viability of bovine embryos derived from oocytes matured and fertilized in vitro and co-cultured with bovine oviducal epithelial cells

“…It has been observed that changes in the synthesis and secretion of oviducal polypeptides are associated with the oestrous cycle in cattle (Malayer et al, 1988) and sheep (Buhi et al, 1989). Indeed, the oviducal cell co-culture system has been extensively used for early embryos in dom¬ estic species, including cows (Eyestone & First, 1989;Pollard et al, 1989;Ellington et al, 1990a, b, c), pigs (White et al, 1989), sheep (Gandolfi & Moor, 1987), goats (Sakkas et al, 1989), and horses (Ball & Altschul, 1990;Weber et al, 1990), as well as in humans (Sathananthan et al, 1990). Oviducal epithelial cells have also been shown to maintain the motility and fertilizing capacity of bovine spermatozoa in vitro (Pollard et al, 1991).…”

Fragmentation of embryos is associated with both necrosis and apoptosis

“…Mitochondrial deficiency of the fragments indicates depletion of ATP in the cells; depletion of ATP is one of the characteristics of necrotic cells and could lead to cell lysis. Previous ultrastructural observations indicate that blastomeres adjacent to the fragments exhibit early signs of vascular degeneration (26). This has raised the possibility that lysing fragments release toxic substances that damage neighboring blastomeres (1).…”

“…Many investigators have reported not only the detrimental effects of fragments on neighboring blastomeres including loss of essential organelles (27), reduced blastocyst formation (2), decreased chances of implantation (1,4), and increase in abortion rate (4,26) but also the beneficial effects of fragment removal on the cells such as improvement of embryo quality (18), blastocyst development (28), and clinical outcome (29). The beneficial effects of fragment removal were also observed in the present study, indicating that the fragments do indeed have a detrimental effect on nearby blastomeres.…”