Prenatal Exposure to Bisphenol A Analogues on Female Reproductive Functions in Mice

Abstract

This study was performed to examine whether prenatal exposure to bisphenol (BP) A analogues, BPE and BPS, negatively impacts female reproductive functions and follicular development using mice as a model. CD-1 mice were orally exposed to control treatment (corn oil), BPA, BPE, or BPS (0.5, 20, or 50 µg/kg/day) from gestational day 11 (the presence of vaginal plug = 1) to birth. Exposure to BPA, BPE, and BPS accelerated the onset of puberty and exhibited abnormal estrous cyclicity, especially with lower doses. Females exposed to BPA, BPE, and BPS exhibited mating difficulties starting at 6 months of age. By 9 months, mice exhibited various fertility problems including reduced pregnancy rate, parturition issues, and increased dead pups at birth. Furthermore, the levels of serum testosterone were elevated by BPE or BPS exposure at the age of 9 months, whereas estrogen levels were not affected. On the other hand, the dysregulated expression of steroidogenic enzymes was observed in the ovary at 3, 6, or 9 months of age by BPE or BPS exposure. When we examined neonatal ovary on postnatal day 4, BPA, BPE, and BPS exposure inhibited germ cell nest breakdown and reduced number of primary and secondary follicles. These results suggest that prenatal exposure to BPA analogues, BPE, and BPS, have effects on fertility in later reproductive life probably due to the disruption of early folliculogenesis.

Keywords: bisphenol A; bisphenol S; mice; ovary; reproduction.