<p>Mixed exposure to trace metals (such as manganese, iron, and copper) may cause significant damage to the nervous system, potentially leading to neurodegenerative diseases. This study aimed to investigate the toxic effects of mixed exposure to manganese, iron, and copper on PC12 cells and its mechanisms, and to evaluate the therapeutic effects of sodium para-aminosalicylic acid (PAS-Na). We employed various experimental techniques, including 3-(4,5-dimethylthiazol- 2-yl)- 2,5-diphenyltetrazolium bromide assay (MTT assays), flow cytometry, and western blotting, to systematically analyze cell viability, redox homeostasis, copper ions concentration, and the expression of cuproptosis-related proteins. The results showed that mixed exposure to manganese, iron, and copper significantly reduced the viability of PC12 cells, and increased intracellular reactive oxygen species (ROS) and copper ions concentration. At the same time, Glutathione (GSH) levels significantly decreased, indicating that the cells were affected by oxidative stress. Further analysis revealed that the increased copper ions concentration was closely related to the upregulation of CTR1 protein expression and the downregulation of ATP7 A protein expression, suggesting a link between copper ions accumulation and the ensuing cell death. Notably, PAS-Na treatment significantly restored cell viability and reversed the increase in copper ions concentration and oxidative stress caused by mixed exposure to manganese, iron, and copper. PAS-Na also reversed the expression of cuproptosis-related proteins, indicating its potential for neuroprotection. These findings provide important insights into the mechanisms of trace metal-induced cell damage and lay the groundwork for the future development of related drugs and therapeutic strategies, warranting further exploration of PAS-Na's clinical efficacy.</p>