Effect of embryo developmental stage and culture conditions on number and quality of ovinein vitroproduced blastocysts

Abstract

This study evaluated the final output and quality of in vitro produced blastocysts derived from in vivo recovered sheep embryos cultured at various early developmental stages to blastocyst. A total of 270 embryos were recovered from the oviduct, at different days of the early luteal phase, and were classified into three different developmental stages: 2- to 4-cell (n = 93); 5- to 8-cell (n = 92) and 9- to 12-cell (n = 85). The effect of culture conditions was studied, at the same time, by randomly allocating the embryos to one of four groups: three groups of culture with fresh oviduct monolayers (2, 4 and 5 days old) and a fourth group with 2-day monolayers derived from frozen-thawed oviduct cells. Two control groups were established: first, embryos cultured in semi-defined medium (n = 29) and, second, blastocysts obtained in vivo and cryopreserved (n = 43). Influence on blastocyst yield of embryo developmental stage at the start of culture was statistically significant (p < 0.001). Two- to four-cell embryos showed a significantly lower developmental rate (67.7%) than the 5- to 8-cell (83.6%; p < 0.001) and 9- to 12-cell groups (90.5%; p < 0.0001) and lower quality in terms of blastocyst cryotolerance (56.0 vs. 83.7%; p < 0.005). There were no detected effects relating to the age or handling of the monolayer on the embryo developmental rate, but the day of blastocyst appearance was different between embryos cultured on monolayers derived from fresh or frozen-thawed cells (p < 0.0001); the main influence was on the group of 9- to 12-cell embryos (p < 0.0001). Current results confirm the temporal sensitivities of sheep embryos to in vitro culture, regardless of the culture conditions.

Effect of embryonic fibroblast cell co-culture on development of mouse embryos following exposure to visible light

“…However, visible light also has some adverse effects on embryos as well as oocytes. The stage of embryo is an important factor that determines the extent of harmful effects of light [12]. Experiments on preimplantation rabbit embryos have shown that after exposure of embryos to 1,600 lx visible light for 8 h the development of day-1 embryos had decreased.…”

Produção in vitro de embriões de ovinos: uma visão crítica do método e de seu resultado a campo

“…O cultivo embrionário pode ser feito em meios definidos, semi-definidos com BSA ou FCS ou em co-cultivo com células tubáricas ou da granulosa (Cognié et al, 2003;Garcia-Garcia et al, 2006). O mais utilizado é o meio SOF-Fluido Sintético do Oviduto, acrescido de amino-ácidos e BSA, que mimetiza o ambiente intratubárico nas primeiras fases do desenvolvimento embrionário (Cognié et al, 2004).…”