Culture of Preimplantation Mouse Embryos

The preimplantation mammalian embryo develops as a free living entity within the mother. This internal development inherently precludes facile experimental manipulation necessary to study cellular and molecular mechanisms of preimplantation development. In turn, this has led to intense efforts over the course of decades to develop culture media that support the preimplantation development in vitro and, in particular, mouse preimplantation development. By the mid-1960s and early 1970s, these efforts led to the development of media such as Brinster’s modified oocyte culture (BMOC) (1 ) and Whitten’s medium (2 ). Further research examined the effect of the composition of the gas phase and led to the general conclusion that 5% oxygen was better than 21% oxygen, which is present in air. In addition, an empirically driven approach led to the formulation of culture media that supported development in vitro of one-cell embryos to the blastocyst stage (3 ,4 ) and overcame the two-cell block, which is exhibited following the culture of one-cell embryos obtained from outbred or inbred mice; embryos obtained from F1 hybrid mice do not exhibit the two-cell block.