Effect of Self-Assembled Polydopamine Nanoparticles on Ferroptosis in an MPTP-Induced Parkinson’s Disease Mice Model

Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons in the striatum and substantia nigra (SN), which currently lacks effective therapeutic interventions. Polydopamine nanoparticles (PDA NPs), which are self-assembled from dopamine, have shown significant potential in the field of neuroscience. This study explored the effects and mechanisms of self-assembled PDA NPs in an MPTP-induced PD mice model. It was observed that mice treated with PDA NPs demonstrated notable improvements in PD motor symptoms. Moreover, PDA NPs reduced the abnormal accumulation of α-synuclein (α-Syn) and increased the expression of tyrosine hydroxylase (TH) in both the striatum and SN. Regarding the neuroprotective mechanism, PDA NPs were found to reduce the iron deposition and Fe²⁺ level in the striatum and SN by modulating the levels of iron transport proteins TF, TFR, and FPN1, thereby attenuating lipid peroxidation caused by Fe²⁺ homeostasis imbalance. Furthermore, PDA NPs upregulated the expression of antioxidant enzyme GPX4, which further diminished cellular lipid peroxidation and provided a protective effect on dopaminergic neurons. These findings suggested that PDA NPs might play a neuroprotective role by inhibiting ferroptosis in the striatum and SN in the PD mice model, which indicated that PDA NPs are promising agents for treating PD.