CoCrMo nanoparticle induces neurotoxicity mediated via mitochondrial dysfunction: a study model for implant derived nanoparticle effects.

Toxicity associated with elevated levels of cobalt-chromium-molybdenum (CoCrMo) nanoparticles in total hip replacement (THR) patients has been a rising concern. Recent investigations demonstrated that these particles can induce polyneuropathy in THR patients. The current study aims to address a detailed molecular investigation of CoCrMo nanoparticle-mediated mitochondrial dynamics using induced pluripotent stem cell-derived neurons (iPSC neurons). Telencephalic neurons from iPSCs were used in this study. A statistically significant dose-dependent reduction in membrane potential and mitochondrial superoxide generation was observed after CoCrMo nanoparticle treatment. The gene expression analysis confirmed that the oxidative-specific genes were significantly upregulated in particle-treated cells compared to untreated cells. When iPSCs were exposed to CoCrMo nanoparticles, there was a significant reduction in the area, perimeter, and length of mitochondria. Live cell imaging (mitochondrial tracking) revealed a significant reduction in mitochondrial movements in the presence of CoCrMo nanoparticles. Further protein expression confirmed increased mitochondrial fission in CoCrMo particle-treated cells by significantly upregulating Drp-1 protein and downregulating Mfn-2. In conclusion, the results show that CoCrMo nanoparticles can significantly alter neuronal mitochondrial dynamics. The disturbance in balance restricts mitochondrial movement, reduces energy production, increases oxidative stress, and can cause subsequent neurodegeneration.