Human chorionic gonadotropin improves endometrial receptivity by increasing the expression of homeobox A10

Homeobox A10 (HOXA10) is a characterized marker of endometrial receptivity. The mechanism by which hCG intrauterine infusion promotes embryo implantation is still unclear. This study seeks to investigate whether hCG improves endometrial receptivity by increasing expression of HOXA10. HOXA10 expression with human chorionic gonadotropin stimulation was analyzed in vitro and in vivo. Our results demonstrate that HOXA10 was decreased in the endometria of recurrent implantation failure patients compared to that in the healthy control fertile group, also we observed that hCG intrauterine infusion increased endometrial HOXA10 expression. HOXA10, blastocyst-like spheroid expansion area was increased, whereas DNA (cytosine-5-)-methyltransferase 1 was decreased when human endometrial stromal cells (hESCs) were treated with 0.2 IU/ml of hCG for 48 h. HOXA10 promoter methylation was also reduced after hCG treatment. Collagen XV (ColXV) can repress the expression of DNA (cytosine-5-)-methyltransferase 1, and hCG treatment increased the expression of ColXV. However, when the hESCs were treated with LH/hCG receptor small interfering RNA to knock down LH/hCG receptor, hCG treatment failed to repress DNA (cytosine-5-)-methyltransferase 1 expression or to increase ColXV expression. Our findings suggest that hCG may promote embryo implantation by increasing the expression of HOXA10.