Fertilization in vitro of mouse ova from inbred and outbred strains: complete preimplantation embryo development in glucose-supplemented KSOM.

A new medium derived from the use of sequential simplex optimization methods (SOM) that overcomes the block to development beyond two cells in vitro in embryos of the CF1-cultured strain of mouse has recently been described. Contrary to previous reports, glucose was shown to have no significant inhibiting effect on embryo development to the blastocyst stage in SOM. A modification of SOM, designated KSOM, with an increased concentration of Na+ (95 mM) and K+ (2.5 mM), which has been described elsewhere, also supports growth beyond the two-cell block. KSOM produces a higher rate of compaction, a larger yield of blastocysts, and an increased rate of cell division of the trophoblast cells. We have reexamined the glucose effect by varying the concentration of glucose (either 0.2 mM or 5.56 mM) in KSOM and determined the ability of these media to support preimplantation development of CF1 female x B6D2F1 male zygotes through the blastocyst stage. Glucose is shown to have no significant inhibiting effect on development to the blastocyst stage. The yield of blastocysts is typically 85%-90%. A modification of KSOM derived from this study, designated modified KSOM, with an increased concentration of glucose (5.56 mM) and supplemented with 4 mg ml-1 BSA is now shown to support high rates of fertilization in vitro of CF1 ova with hybrid B6D2F1/CrlBR sperm and subsequent development of zygotes beyond the two-cell stage to blastocysts in high yield.(ABSTRACT TRUNCATED AT 250 WORDS)