Inhibitory effect of human hydrosalpingeal fluid on mouse preimplantation embryonic development is significantly reduced by the addition of lactate.

Implantation and pregnancy rates following in-vitro fertilization-embryo transfer are reduced in the presence of hydrosalpinges, but the basis of the inhibition is unknown. We examined the effect of hydrosalpingeal fluid on preimplantation development of mouse embryos. Embryos cultured in 100% hydrosalpingeal fluid were significantly inhibited developmentally as compared to embryos cultured in 100% defined medium, which served as controls. In contrast, embryos cultured in 50% hydrosalpingeal fluid/50% defined medium reached the blastocyst stage at the same frequency as the controls. When lactate (final concentration 10 mM) was added to 100% hydrosalpingeal fluid, the percentage of cultured embryos that reached the blastocyst stage was significantly increased as compared to 100% hydrosalpingeal fluid, although the percentage was slightly lower than that observed for embryos cultured in the 100% defined medium. A similar but less pronounced effect occurred when pyruvate was added to hydrosalpingeal fluid. These results do not support the concept that a potent embryotoxic agent is commonly present in hydrosalpingeal fluid. Rather, they are consistent with the notion that the inhibitory effect of hydrosalpingeal fluid on embryonic development is due to the absence of essential factors, and that this deficiency can be largely corrected by the addition of energy sources.