Effect of tetrabromobisphenol A (TBBPA) on early implantation using the three-dimensional spheroid model with human endometrial cell line, Ishikawa

Abstract

Abstract Background Tetrabromobisphenol A (TBBPA) can be characterized as an endocrine-disrupting chemical (EDCs). It has been widely used as a brominated flame retardant in industrial products. EDCs have effects on female reproduction leading to issues, such as infertility, hormone imbalance, and endometriosis. In Korea, the problems of infertility and decreasing birth rate are of significant concern. Exposure to EDCs might have a harmful effect on female fertility by mediating a decrease endometrial receptivity. This study aimed to investigate the effects of TBBPA on infertility, particularly on early implantation events in the uterine endometrium. Human endometrial adenocarcinoma and trophoblastic cell lines were used in this study. The cytotoxicity of TBBPA on Ishikawa cells and Jeg-3 cells was measured using the Cell Counting Kit-8 assay. The mRNA expression was analyzed by reverse transcription-quantitative polymerase chain reaction, and protein levels were measured by western blotting. The attachment rate was analyzed using an attachment assay, and the outgrowth area was measured using an outgrowth assay. Results The mRNA expression of interleukin (IL)-6, IL-1β, tumor necrosis factor-α, and leukemia inhibitory factor was significantly increased upon treatment of Ishikawa cells by TBBPA. Moreover, the outgrowth area in the TBBPA group was significantly decreased compared to that in the control. In contrast, TBBPA had a minor effect on protein levels and attachment rates. Conclusions In this study, TBBPA induced an inflammatory milieu in mRNA expression. An increase in inflammation-related cytokines in the endometrium can disrupt embryo implantation. TBBPA disrupted the outgrowth of spheroids in the endometrium; however, the protein levels and attachment rate were comparable to those in the control group. The effect of TBBPA on implantation events should be elucidated further.