Adavances in the study of folate as a potential modulator of oviductal function: new evidences at molecular level

Abstract

Numerous studies have shown that folate has important reproductive implications in mammals during post-implantation embryonic and fetal development. However, little is known about its action in the oviduct, the organ that provides the first maternal environment that interacts with the embryo. In previous studies, we demonstrated the presence of folate in oviductal fluid (OF) and the expression of folate receptors in bovine oviductal epithelial cells (BOECs). In addition, folate concentration in OF decreases during the post-ovulatory stage, while the expression of its receptor FOLR1 increases in BOECs of the isthmus. These facts allow us to suggest that, after ovulation, the demand for folate increases in the anatomical region of the oviduct that will make contact with the embryo. Considering these findings, the aim of the present study was to determine whether BOECs contains the molecular components necessary to metabolize and use this micronutrient. To achieve this, gene expression pattern of enzymes related to folate cycle was assessed using RT-qPCR in different reproductive tissues and BOECs obtained ex vivo and cultured in vitro. The results revealed the gene expression of the three main enzymes involved in folate metabolism (DHFR, MTHFR, and MTR) in the BOECs, showing in some cases regional and cycle-dependent changes. The oviduct shows the highest expression levels compared to other reproductive tissues (uterus and ovary) and BOECs maintain gene expression of the enzymes under in vitro culture conditions. These results indicate that BOECs have the machinery to metabolize folate. Therefore, it is interesting to further investigate the impact of this “epi-nutrient” in the oviductal context.