Expression of leukemia inhibitory factor receptor and gp130 in mouse uterus during early pregnancy

Leukemia inhibitory factor (LIF) is essential for implantation of mouse embryos. The aim of this study was to assess the expression and regulation of LIF receptor (LIFR) and gp130 mRNA in mouse uterus during early pregnancy using in situ hybridization and reverse transcription-polymerase chain reaction (RT-PCR). A strong level of LIFR mRNA signal was detected in the luminal epithelium on day 5 of pregnancy. On day 6-8 of pregnancy, LIFR signal was mainly localized in the decidua. LIFR signal in the luminal epithelium of ovariectomized mouse was slightly stimulated by a combination of progesterone and estrogen. By RT-PCR, LIFR mRNA signal was detected in all of the uteri from day 1-8 of pregnancy, being at the highest level on day 5. A low level of gp130 mRNA signal was seen in the glandular epithelium on day 3 of pregnancy and reached a high level on day 4 of pregnancy. gp130 signal in the decidua appeared on day 6 of pregnancy and reached a high level on day 7 and 8 of pregnancy. After the ovariectomized mouse was treated with a combination of progesterone and estrogen, a strong gp130 signal was observed in the glandular epithelium, while no signal was detected after progesterone or estrogen treatment alone. By RT-PCR analysis, gp130 mRNA was detected in all of the uteri from day 1-8 of pregnancy, being at the highest level on day 4 of pregnancy. Additionally, a high level of LIFR and gp130 mRNA signal was detected in the decidua under artificial decidualization compared to the control uninjected horn. The co-expression of a high level of LIFR and gp130 mRNA in the decidua may play a key role during the decidualization and placentation.