Sequential culture and coculture are two methods of improving the development of preimplantation
embryos in vitro. Direct comparison of the efficiency of these methods is limited. Proliferation and
apoptosis determine the total number of
blastomere in preimplantation
embryo, which is a sensitive parameter for evaluation of the development of
embryo in vitro. In this study, we compared the proliferation and
apoptosis of
mouse embryo in different
culture media, including CZB, KSOM, MTF, G1.2/G2.2 sequential
culture media, and in human oviductal cell coculture. Sequential culture using G1.2/G2.2 was superior to KSOM, MTF, and CZB/CZB + G
with respect to the formation of 3-4 cell
embryos,
morula, and
blastocyst. G1.2/G2.2 cultured
blastocyst had significantly more proliferating
blastomeres and higher total cell number per
blastocyst than those cultured in KSOM or CZB/CZB + G. Compared to
embryos cultured in G1.2/G2.2,
embryos cocultured in G1.2/G2.2 hatched more frequently. Cocultured
blastocysts also had significantly higher percentage of proliferating cell and lower percentage of
apoptotic cell per
blastocyst than those cultured in G1.2/G2.2. It was concluded that G1.2/G2.2 facilitated the proliferation of
blastomere whilst human oviductal cell coculture suppressed
apoptosis in addition to stimulating proliferation of
blastomere.
