Evaluation of co-culture and alternative culture systems for promoting in-vitro development of mouse embryos.

The goal of this study was to compare mouse embryo development in a defined synthetic medium (human tubal fluid) against the same medium supplemented with a defined synthetic serum (SS), co-culture on human tubal epithelium (TECC), and culture on human fibronectin (FN) with and without SS. After 48 h, TECC, SS and FN + SS cultures demonstrated accelerated development with > 70% achieving > or = 8-cell stage. After 72 h, these culture conditions also significantly increased the proportion of embryos reaching the blastocyst stage but only TECC significantly increased the number of hatching blastocysts. Nuclei of the trophectoderm of unhatched and hatched blastocysts were stained with propidium iodide before fixing and labelling both the trophectoderm and inner cell mass with bisbenzimide. Blastocysts from the TECC contained a significantly higher total cell number (TCN) and trophectoderm and inner cell mass cell numbers than all other groups. These findings indicate equivalent improvements in mouse embryo development to the blastocyst stage in response to TECC, SS and FN and an enhanced number of cells and rate of hatching found only with TECC.