Toxicological impact of tetrabromobisphenol-A on pregnant rats: Morphological, biochemical, and histopathological investigations

Tetrabromobisphenol-A (TBBPA) is found in high concentrations in textiles, plastic polymers, flame retardants, and various industrial products. In this maternofetal study, we aimed to evaluate the potential effects of TBBPA on the mother, fetus, and placenta in pregnant rats. In the experimental design, three different gestational days (GD10, GD15, and GD20) were selected for evaluation in pregnant rats. For each gestational period, one control group (corn oil) and three TBBPA dose groups (20, 200, and 400 mg/kg) were established, resulting in a total of 12 experimental groups. Each group included six pregnant rats. We hypothesized that TBBPA exposure would lead to alterations in maternal and fetal hormonal and placental parameters when evaluated across different doses and gestational days. Placenta, kidney, liver, and ovary tissues were examined histopathologically. Levels of follicle-stimulating hormone (FSH), progesterone, luteinizing hormone (LH), and estrogen were analyzed. Estrogen from ovarian homogenates and testosterone from testicular homogenates of GD20 fetuses were also measured. We detected statistically significant differences in placental and fetal data. However, no severe effects were observed. Serum FSH levels were elevated in the GD20 group receiving 400 mg/kg, whereas LH levels increased in the GD15 group at both 200 and 400 mg/kg compared to controls. In GD20 female fetuses, estrogen levels decreased at 20 mg/kg but increased at 200 mg/kg relative to the control group. Histopathological examination of placental tissue revealed congestion, degeneration in the labyrinth region, cytoplasmic dissolution and pyknosis in giant cells, and degeneration in spongiotrophoblasts. No severe systemic toxicity was observed in our study. However, the mild to moderate level changes detected highlight the need for further investigation of TBBPA, especially considering the uncertainties regarding its effects during pregnancy.