RXRα is upregulated in first trimester endometrial glands of spontaneous abortions unlike LXR and PPARγ.

Nuclear receptors are necessary for uterine invasion of the trophoblast and therefore important for maintaining a viable pregnancy. The aim of this study was to investigate the expression pattern and frequency of LXR, PPARγ and RXRα under physiological circumstances and in spontaneous abortions in endometrial glands and decidual tissue cells. A total of 28 (14 physiologic pregnancies/14 spontaneous abortion) human pregnancies in first trimester were analysed for expression of the nuclear receptors LXR, RXRα and PPARγ. Expression changes were evaluated by immunohistochemistry in decidual tissue and endometrial glands of the decidua. RXRα expression was up-regulated in the endometrial glands of spontaneous abortion (P<0.015). Similar up regulation of RXRα was found in decidual tissue (P<0.05). LXR and PPARγ expression was unchanged in spontaneous abortion. Via Correlation analysis we found a trend to positive correlation of LXR and PPARγ (Spearman correlation coefficient r=0.56 P=0.07) in endometrial glands. In decidual tissue, we found significant negative correlation in the control group, for the combination of RXRα and PPARγ (Spearman correlation coefficient r=0.913, P=0.03). Our data show that RXRα expression is increased in miscarriage in endometrial glands and correlation analysis showed that negative correlation between RXRα and PPARγ disappears in miscarriage. This shift is supposable responsible for the loss of regular function in trophoblast and embryonic tissue.