Bisphenol A and bisphenol AF co-exposure induces apoptosis in human granulosa cell line KGN through intracellular stress-dependent mechanisms

Bisphenol A (BPA) is a chemical substance used in large amounts in the production of epoxy resins, phenolic resins and polycarbonate plastics. Although its toxicity to the female reproductive system has been extensively studied, little is known about the combined toxicity of BPA and its analogues. In this study, the human granulosa cell line KGN was co-exposed to BPA and bisphenol AF (BPAF), and we subsequently examined the effect of these chemicals on cell apoptosis and their mechanism. We found that co-exposure to BPA and BPAF induced intracellular stress in KGN cells, including significantly elevated levels of reactive oxygen species (ROS) and calcium ions (Ca²⁺). Then, apoptosis and its associated biological events, including increased caspase-3 activity, and decreased Bcl-2/Bax protein expression ratio, were measured under the combined exposure. Notably, we confirmed that the intracellular stress and activation of the signaling axis of the downstream ASK1-JNK signaling pathway involved in the apoptosis of KGN cells was induced by the mixture of BPA and BPAF. In addition, we verified with pretreatment inhibitors that the BPA and BPAF mixture promoted the co-induction of KGN cell apoptosis via this stress pathway. Our work provides novel insights into the combined cytotoxicity and molecular toxicity mechanism of bisphenol mixtures.