Bisphenol A induces apoptosis and disrupts testosterone synthesis in TM3 cells via reactive oxygen species-mediated mitochondrial pathway and autophagic flux inhibition

Bisphenol A (BPA) is a common endocrine disruptor chemical that is widely used in the production of food plastic packaging, and it has been shown to potentially harm the reproductive system. However, the specific mechanism by which BPA induces apoptosis of Leydig cells (LCs) and inhibits testosterone synthesis in these cells is unclear. In the present study, TM3 cells were used as an experimental model in combination with a reactive oxygen species (ROS) scavenger (N-acetylcysteine), Caspase-3 inhibitor (Ac-DEVD-CHO), autophagy activator (Torin2), and autophagy inhibitor (Chloroquine) to investigate the potential mechanisms by which BPA causes TM3 cell damage in vitro. BPA treatment increased ROS production, which led to a marked decrease in antioxidant enzyme activity and the expression levels of antioxidant-related genes and proteins in TM3 cells. Upregulated ROS cause excessive opening of the mitochondrial permeability transition pore and significantly decrease the expression levels of genes related to membrane potential and mitochondrial function in TM3 cells. The release of cytochrome C from damaged mitochondria into the cytoplasm activated a Caspase cascade reaction. In addition, excessive ROS levels impaired autophagic degradation by inhibiting the fusion of autophagosomes with lysosomes. These abnormalities eventually induced apoptosis and inhibited testosterone synthesis in TM3 cells. The collective findings suggest that BPA induces apoptosis and interferes with testosterone synthesis in TM3 cells by upregulating ROS production, thereby activating the mitochondrial apoptotic pathway and inhibiting autophagic flux. These findings provide novel mechanistic insights into male reproductive toxicity caused by BPA exposure.