[Effects of basic fibroblast growth factor on the development of mouse preimplantation embryos]

Basic fibroblast growth factor (bFGF) is known to be a mesoderm inducer of the Xenopas embryo, although the role of this factor in mammalian preimplantation embryos is not known. This study was performed to examine possible roles of bFGF in murine preimplantation development. To determine the expression of bFGF and FGF receptor 1 (FGFR 1) mRNA in mouse embryos and uterine endometrial epithelial cells, a reverse transcription-polymerase chain reaction (RT-PCR) technique was used. In the mouse embryos, bFGF mRNA was not detected but FGFR 1 mRNA was expressed in the blastocyst stage. Long and short forms of FGFR1 mRNA generated by alternative splicing were expressed. Both bFGF and two forms of FGFR 1 mRNA were detected in mouse endometrial epithelial cells. Immunoblot analysis indicated that bFGF protein was present in the uterine luminal fluid during the preimplantation period, and the level of expression of the protein was relatively constant. The addition of bFGF to the culture medium had no effects on the rate of blastocyst formation of 2 cell stage embryos, but it significantly increased the protein synthesis in blastocysts. These results suggest that bFGF derived from the mouse uterine endometrium affects the development of preimplantation embryos in a paracrine fashion.