150 IN VITRO MODEL FOR EFFECT OF ENDOCRINE-DISRUPTING CHEMICALS ON PLACENTAL CATION TRANSPORTER CHANNEL

Abstract

Calcium, copper, iron, oxygen, and carbon dioxide are essential factors in fetal growth. These molecules are transferred by specific receptors located on the cell membrane or cytoplasm in placenta. Calcium, copper, and iron transfer genes are regulated by oestrogen, placental lactogen, and vitamin D. During pregnancy, expression of these receptors is controlled by the nutritional status of the maternal and fetal environment. Some synthetic plastics contain endocrine-disrupting chemicals (EDC), which have similar structures to steroid hormones or endogenous hormones related to reproduction. These substances disturb action of hormones (e.g. increasing oestrogen or progesterone) by interacting with their receptors or affecting the expression of transporting genes for cations. We used a BeWo cell line (human trophoblast cell line) to test the effect of EDC during pregnancy. The cells were cultured in phenol red-free DMEM supplemented with 5% charcoal dextran-stripped fetal bovine serum for 48 h to ensure the depletion of steroid hormones in the cells. Ethinyl oestradiol (EE), which activates oestrogen receptors, was used as a positive control. Then, EE (10–9, 10–8, and 10–7 M), octylpehnol (OP; 10–7, 10–6, and 10–5 M), nonylphenol (NP; 10–8, 10–7, and 10–6 M), and bisphenol A (BPA; 10–7, 10–6, and 10–5 M) were treated in BeWo cells for 48 h, and the cells were harvested. The mRNA and protein levels for calcium transporting genes (PMCA1 and TRPV6), copper transporting genes (CTR1 and ATP7A), and iron transporting genes (IREG1 and HEPH) were quantified by RT-qPCR, and Western blotting, respectively. Experiments were carried 3 times, and results were statistically analysed by GraphPad Prism6 (GraphPad Software, San Diego, CA, USA). We observed dose-dependent decreases in mRNA levels of PMCA1, TRPV6, ATP7A, and IREG1 compared with control group in OP-, NP-, or BPA-treated groups. Protein levels showed a similar pattern to mRNA levels. Based on our data, we confirmed that these EDC affect metal ion channels such as calcium, copper, and iron transporters during pregnancy.