The Effects of Leukemia Inhibitory Factor on Development of Mouse Preimplantation Embryo

Introduction and Recent studies have demonstrated that mammalian preimplantation embryos are exposed to a mixture of many different growth factors and cytokines, expressed by the follicles, oviducts and endometrium. Receptors for many of these growth factors have also been shown to be expressed by preimplantation embryos. In vitro culture of human and animal's embryos in conventional media lacking growth factors can result in suboptimal growth and a variety of short-term and long-term developmental abnormalities. One of these factors is Leukemia Inhibitory Factor (LIF). The aim of this study was to evaluate the effects of LIF on the mouse preimplantation embryo development. Six to eight weeks old NMRI mice were superovulated by injection of 10IU PMSG and 10IU HCG 48h later. The mated mice were killed 48 hours after HCG injection, oviducts were flushed and two-cell embryos were collected and divided randomly to two groups (control and treatment). Control medium was HTF and treatment medium was HTF+1000u/ml LIF. In each group the embryos were cultured in an incubator at 37°C with 5% CO2 for 72h.The state of embryo development was evaluated in 12 hours interval using inverted microscope. There was not any significant difference in the rate of morolla and blastocyst formation after 36 hours. In comparing hatching rates, 60 and 72 hours after culture, there were significant difference between control and treatment groups (p< 0.008). LIF doesn’t provide obvious stimulation in the early mouse embryo development until morolla stage. However, it has positive effects on preimplantation blastocyst growth, differentiation and hatching.