Background: Reduced glutathione and excess free iron within dopaminergic, substantia nigra neurons in Parkinson's disease (PD) can drive accumulation of toxic hydroxyl radicals resulting in sustained oxidative stress and cellular damage. Factors such as brain penetrance and bioavailability have limited the advancement of potential antioxidant and iron chelator therapies for PD.
Objective: This study aimed to develop novel nanocarrier delivery systems for the antioxidant curcumin and/or iron chelator deferoxamine (DFO) to protect against rotenone-induced changes in cell viability and oxidative stress in SH-SY5Y cells.
Methods: Nanocarriers of curcumin and/or DFO were prepared using Pluronic F68 (P68) with or without dequilinium (DQA) by modified thin-film hydration. Cell viability was assessed using an MTT assay and oxidative stress was measured using thiobarbituric acid reactive substances and cellular antioxidant activity assays.
Results: All formulations demonstrated high encapsulation efficiency (65-96%) and nanocarrier size was <200 nm. 3-h pretreatment with P68 or P68+DQA nanocarriers containing various concentrations of curcumin and/or DFO significantly protected against rotenone-reduced cell viability. The addition of DFO to curcumin-loaded P68+DQA nanocarriers resulted in increased protection by at least 10%. All nanoformulations significantly protected against rotenone-induced lipid peroxidation (p < 0.0001). The addition of DQA, which targets mitochondria, resulted in up to 65% increase in cellular antioxidant activity. In nearly all preparations, the combination of 10 μM curcumin and 100 μM DFO had the most antioxidant activity.
Conclusion: This study demonstrates for the first time the formulation and delivery using P68 and P68+DQA curcumin and/or DFO nanocarriers to protect against oxidative stress induced by a rotenone PD model. This strategy to combine antioxidants with iron chelators may provide a novel approach to fully utilise their therapeutic benefit for PD.