생쥐의 착상시기 배아와 자궁내막세포에서 IL-1에 의한 LIF 유전자 발현 조절 = Regulation of LIF gene expression by interleukin-1 in the mouse peri-implantation embryos and uterine endometrial cells

다국어 초록 (Multilingual Abstract)

In mouse, interleukin-1 (IL-1) system and leukemia inhibitory factor (LIF) are essential for successful implantaion. In this experiment, LIF mRNA expression was examined by RT-PCR in the embryos and uterine endometrial cells of pregnant mouse treated with IL-1β or IL-1ra to investigate the relationship between IL-1 and LIF in the implantation process.
In the embryos, IL-1β mRNA was detected from 4-cell to blastocyst stage in vivo, and LIF mRNA was detected from morula to blastocyst stage in vivo and in vitro. In the uterine endometrial cells, IL-1β mRNA levels were increased from day 3 of pregnancy to make a peak at the time of implantation on day 4, and LIF mRNA was detected in the endometrial cells of day 1 and day 4 of pregnancy, but the amount of LIF mRNA was abundant in the endometrial cells of day 4 of pregnant mouse uterus.
Electrophoresis demonstrates that when 2-cell embryos were cultured in the medium containing IL-1β (500 pg/ml), LIF mRNA was detected from 8-cell to blastocyst stage embryos. In addition, the amount of LIF mRNA was shown a tendency to increase in blastocyst stage embryos compared with the embryos cultured in the medium alone. But LIF mRNA was reduced in morula and blastocyst stage embryos treated with IL-1ra (60 ng/ml). In case of the endometrial cells treated with IL-1β, LIF mRNA was detected from day 1 to day 5 of pregnancy. That is, LIF mRNA expression in the endometrial cells on day 2, 3 and 5 of pregnancy by IL-1β. On day 4 of pregnancy, LIF mRNA was reduced in the endometrial cells treated with IL-1ra, when compared with the endometrial cells treated with IL-1β or medium alone. Furthermore, on day 1 of pregnancy, LIF mRNA expression was not detected from the endometrial cells.
Immunohistochemical analysis of the endometrial cells cultured in vitro indicates that cultured endometrial cells consisted with the above 90% of epithelial cells that have an ability to express the LIF mRNA.
These results imply that LIF mRNA expression is up-regulated by IL-1β, but down-regulated by IL-1ra in the embryos and the endometrial cells during peri-implantation period. Thus, it is suggested that the uterine receptivity should be prepared by the interaction between IL-1β and LIF during peri-implantation process.