Recombinant human leukemia inhibitory factor does not enhance in vitro human blastocyst formation.

OBJECTIVE

To assess the effect of human recombinant leukemia inhibitory factor in different doses on human blastocyst formation.

SETTING

A university-based tertiary referral center (The Toronto Hospital).

INTERVENTIONS

Nontransferable human embryos (n = 473) at the two- to six-cell stage were obtained from patients undergoing IVF and were split randomly into five groups. Embryos in group A (n = 164) were cultured as the control group in Ham's F-10 (GIBCO-BRL, Grand Island, NY) + 10% human sera. Embryos in groups B, C, D, and E (n = 54, 78, 87, and 80, respectively) were cultured in the same medium supplemented with human recombinant leukemia inhibitory factor in four different concentrations (5, 7.5, 10, and 20 ng/mL, respectively). Morphological assessment of embryo development was recorded daily.

MAIN OUTCOME MEASURE

Human blastocyst formation.

RESULTS

No significant difference was detected in the rate of blastocyst formation of embryos in the study groups when compared with embryos in group A.

CONCLUSIONS

This study shows that 5 to 20 ng/mL of recombinant leukemia inhibitory factor in standard medium does not enhance in vitro human blastocyst formation. It is possible that recombinant leukemia inhibitory factor may play a role at later stages of human embryogenesis and during implantation.