C-C motif chemokine ligand 2 regulates prostaglandin synthesis and embryo attachment of the bovine endometrium during implantation.

C-C motif chemokine ligand 2 (CCL2) has been reported to be expressed in the bovine endometrium during pregnancy. However, the details of its functions involved in the implantation mechanism are still not clear. The purpose of this study is to analyze the functional properties of CCL2 in the bovine endometrium and embryos. The expression of CCR2 was not different between the luteal phase and implantation phase of their endometrial tissues, but was significantly high in IFNa treated bovine endometrial stromal (BES) cells in vitro. The expressions of PGES1, PGES2, AKR1C4, and AKR1C4 were high at the implantation stage compared with the luteal stage. On the other hand, PGES2 and AKR1B1 in BEE and PGES3 and AKR1A1 in BES were significantly increased by CCL2 treatment, respectively. The expressions of PCNA and IFNt were found significantly high in the bovine trophoblastic cells (BT) treated with CCL2 compared to the control. CCL2 significantly increased the attachment rate of BT vesicles to BEE in in vitro co-culture system. The expression of OPN and ICAM-1 increased in BEE, and ICAM-1 increased in BT by CCL2 treatment, respectively. The present results indicate that CCL2 has the potential to regulate the synthesis of PGs in the endometrium and the embryo growth. In addition, CCL2 has the possibility to regulate the process of bovine embryo attachment to the endometrium by modulation of binding molecules expression.