Culture of pre-implantation Chinese hamster (Cricetulus griseus) embryos in vitro.

Pre-implantation embryos from Chinese hamsters (Cricetulus griseus) were cultivated under completely defined conditions. The embryos were placed in drops of chemically defined medium under liquid paraffin and cultured in an atmosphere of 10% CO2 in air. By this method, development will proceed in vitro from the two-cell stage up to the blastula within 72 h. It is possible to stop the cultivation at different stages of development, to fix the embryos and analyse the chromosomes. The method described in detail seems to be appropriate for examination of the induction of genetic defects during the first days of embryogenesis.