Abstract
Bisphenols belong to the endocrine disruptors, affecting reproduction even in extremely low doses. Bisphenol S (BPS) has become widely used as a substitute for the earlier-used BPA; however, its harmnessless is questionable.
The aim of this study was to evaluate the effect of BPS on folliculogenesis and oocyte quality after in vivo exposure to low doses of BPS. 4-week-old ICR females (N = 16 in each experimental group) were exposed to vehicle control (VC), BPS1 (0.001 ng BPS . g bw-1 . day-1), BPS2 (0.1 ng . g bw-1 . day-1), BPS3 (10 ng . g bw-1 . day-1) and BPS4 (100 ng . g bw-1 . day-1) for 4 weeks. Ovaries were subjected to stereology and nanoLC/MS.
Simultaneously, metaphase II oocyte were obtained after PMSG and hCG administration, followed by immunostaining. In particular, mating and two-cell embryo flushing was performed.
We observed that BPS decreases the amount of ovarian follicles and BPS2 (0.1, ng . g bw-1 . day-1) affects the volume of antral follicles. Accordingly, ovarian proteome is affected after BPS2 treatment.
While BPS2 dosing results mainly in cytoskeletal damage in matured oocytes, the effects of BPS3 and BPS4 seem to be due instead to epigenetic alterations in oocytes. Arguably, these changes lead to observed affection of in vivo fertilisation rate after BPS3 and BPS4 treatment.
BPS significantly affects female reproduction astoundingly in extremely low doses. These findings underline the necessity to assess the risk of ongoing BPS exposure for public health.