Novel insights into male reproductive toxicity: autophagy-dependent ferroptosis triggered by polylactic acid nanoplastics and copper sulfate

Polylactic acid (PLA) plastics are widely used in packaging for their safety and biocompatibility. However, PLA can generate micro/nanoplastics (MNPs), which infiltrate the food chain and pose health risks by adsorbing heavy metals such as copper (Cu) from the natural environment. This study investigated the role of autophagy-dependent ferroptosis in PLA NPs and Cu-induced testicular injury. C57BL/6J mice were orally exposed to 100 nm PLA NPs and copper sulfate (CuSO₄) for 4 weeks. The combined exposure caused significant reproductive toxicity, including reduced sperm counts and motility, increased sperm deformation, damaged blood-testis barrier, and disrupted sex hormone levels. Mechanistically, PLA NPs and CuSO₄ triggered oxidative stress and ferritinophagy, leading to iron overload and ferroptosis in testicular tissue. The critical involvement of this pathway was confirmed using ferroptosis and autophagy inhibitors, which mitigated testicular injury. These findings provide the first evidence of reproductive toxicity induced by bio-based PLA NPs and Cu co-exposure, highlighting the vital role of autophagy-dependent ferroptosis in testicular injury and offering new insights into the combined toxicological effects of nanoparticles and environmental pollutants.