Objective: To determine the effect of leukemia inhibitory factor (LIF) on the quality of in vitro produced mouse
blastocyst and the efficiency of embryonic stem (ES) cell derivation.

Design: Experimental study

Setting: Reproductive Medicine Unit, Department of Obstetrics and Gynecology, Faculty of Medicine,
Chulalongkorn University

Material and Method: In vivo fertilized zygotes were collected and subjected to in vitro culture in potassium
simplex optimized medium (KSOM) containing 1,000 unit/ml LIF. The developmental ability of the zygote to
blastocyst-stage and the cell numbers in blastocysts were evaluated. Expanded blastocysts developed in
different culture media were subsequently subjected to ES cell derivation.

Main Outcome Measure (s): The influence of LIF on the quality of and the total cell numbers of blastocyst
developed in vitro.

Results: Supplementation of LIF in KSOM increased the rate of hatching blastocysts (63.8% vs. 53.7%; p <
0.05) and total cell numbers (91.4 + 15.0 vs. 85.1 + 7.7; p < 0.05) compared to KSOM alone. ES cells were
obtained 66.7% from blastocysts developed in KSOM-LIF versus 41.7% in KSOM (p > 0.05). Established ES
cell lines showed typical colony and characteristics of pluripotent murine ES cells.

Conclusion: LIF improved the quality of in vitro produced blastocysts but not enhanced ES cell derivation.

Keywords: LIF, in vitro, Blastocyst, Embryonic stem cells