Assessment of microplastic toxicity on blood-testis barrier using 3D cell spheroids

Industrial production generates large quantities of microplastics (MPs), which can significantly impact ecosystems and pose potential risks to human health, both directly and indirectly, and the mechanisms and potential toxicity of microplastics affecting the reproductive system remain unclear. In this study, we investigated the cytotoxicity of microplastics on the blood-testis barrier using 3D Sertoli cell spheroids (TM4S) exposed to artificially manufactured primary polystyrene microplastics (MPS). To investigate these effects, we explored the invasiveness of MPS in relation to microplastic size and concentration, and analyzed morphological changes in the cell spheroids. In addition, we evaluated changes in cellular physiological activities. Finally, we detected pathways related to endoplasmic reticulum stress in Sertoli cells (TM4), and revealed that exposure to MPS triggered endoplasmic reticulum stress in TM4S. This model has the potential to deepen our understanding on the microplastic-reproduction interaction and the underlying toxicity mechanisms of microplastics in the reproductive system.