Melatonin helps promote implantation in early pregnancy

Professor Song Gwon-hwa's research team reveals the mechanism of the interaction 

between the mother and the embryo via melatonin.

The research was published in the Journal of Pineal Research, 

a leading journal in the field of endocrinology.

▲ From the left, Dr. Bae Hyo-cheol, doctoral degree student Yang Chang-won, and professor Song Gwon-hwa

The domestic research team has identified that melatonin can improve the implantation ability of embryos in early pregnancy, making headlines. Professor Song Gwon-hwa's research team at the Division of Biotechnology in the College of Life Sciences and Biotechnology, published a study showing that melatonin can facilitate the process of embryo implantation in the mother's womb.

This research, by Dr. Bae Hyo-cheol and doctoral degree student Yang Chang-won as joint first authors, was conducted in collaboration with the research team of professor Fuller W. Bazer of Texas State University, US, and the research team of Lim Wha-sun of the Department of Food and Nutrition in Kookmin University. The results of the study were published online on May 18 in the Journal of Pineal Research (IF: 15.221, top 2.06% of JCR), which is a leading journal in the field of endocrinology, physiology, and brain science.

* The title of the study: Melatonin improves uterine-conceptus interaction via regulation of SIRT1 during early pregnancy

It has been reported that melatonin not only regulates the biorhythm of the body but also contributes to preventing heart and brain damage to the embryo or fetus during pregnancy. Professor Kwon-hwa Song's team used a pig model, which is a valuable in vitro model for pregnancy research, to collect trophectoderm and endometrium tissues from pigs at different periods of pregnancy; and the team confirmed through histological techniques that the expression of melatonin receptors in early pregnancy increased gradually in the collected trophectoderm and endometrium tissues.

▲ Figure 1. Expression patterns of melatonin receptors (MTNR1A, MTNR1B) in trophectoderm and endometrium tissues

In addition, the team confirmed that when trophectoderm cells and endometrium cells were treated with melatonin, the proliferation and migration of the cells increased through activation of the signaling pathways of PI3K and MAPK, which promoted implantation. The team also found that melatonin can inhibit inflammatory responses and endoplasmic reticulum stress responses in trophectoderm and endometrium cells.

In particular, the research team uncovered the SIRT1 gene as a target factor regulated by melatonin in trophectoderm and endometrium cells and confirmed that the effect of melatonin was inhibited when SIRT1 expression was suppressed. Moreover, an experiment using the zebrafish model confirmed that an abnormally generated fertilized egg from a mother exposed to an inflammation-inducing substance (LPS) formed a normal fertilized egg with melatonin treatment.

▲ Figure 2. Protective effect of zebrafish fertilized egg with melatonin administration

This study has revealed a new function of melatonin, the role of which in maintaining pregnancy has been unclear. Professor Song's research team found that melatonin not only contributes to the interaction between the mother and the embryo via the SIRT1 gene, but also protects against inflammatory reactions and stress, thereby assisting the maintenance of a healthy pregnancy environment. The results are significant in that they present the potential use of melatonin in the future for promoting implantation and maintaining pregnancy.