The effects of prenatal exposure to ethinyl estradiol and bisphenol‐A on the developing brain, reproductive organ and behavior of mouse

Abstract

ABSTRACT This study investigated the effects of ethinyl estradiol (EE) and bisphenol‐A (BPA) on the maturation of fetuses, reproductive organ, brain development, and behavior. Twenty‐eight Jcl‐ICR pregnant mice were divided into 0.2 mg/kg of EE, 0.02 mg/kg of EE, BPA and control groups. Pregnant mice belonging to 0.2 mg/kg of EE and 0.02 mg/kg of EE group were daily injected subcutaneously either 0.2 mg/kg or 0.02 mg/kg of EE dissolved in olive oil from 11 to 19 days of gestation. The BPA group received an injection of 100 mg/kg of BPA dissolved in olive oil while the control group received an injection of olive oil alone subcutaneously on the same days of gestation. Neurological and behavioral development was examined by means of the sensorimotor reflexes until day 10 and openfield test on day 40 after birth. Myelination of the brain and maturation of testis were histologically examined. Obtained results were: 1) Pregnant mice in the 0.2 mg/kg EE group had no live births. 2) The mean litter size in the 0.02 mg/kg EE group was smaller than that in the BPA and control groups. The mean body weight at birth and that at the age of 60 days showed no significant differences among groups. 3) In the openfield test at the age of 40 days, the mean number of grooming and line‐crossing in the inner field in the 0.02 mg/kg EE group were significantly higher than those in the control group and the mean number of grooming, rearing and line‐crossing in the outer field in 0.02 mg/kg EE group were significantly higher than those in the BPA group. The mean numbers of defecation in both 0.02 mg/kg EE group and BPA group were less than those in the control group. 4) The mean diameter of seminiferous tubules and number of spermatocytes layers in the 0.02 mg/kg EE group and BPA were significantly less than those in the control group. 5) The mean diameter of tractus mamillothalamics in the 0.02mg/kg EE group and BPA group showed no significant differences compared with that in the control group. These findings suggested that prenatal exposure to EE or BPA adversely affects litter size, openfield behavior and spermatogenesis.