Penetration of the Blood–Brain Barrier and Liver for Repairing Motor Disorders in a Rat Model of Parkinson’s Disease Using a Nanocopolymer

Parkinson's disease (PD) is a neurodegenerative disorder that results in dopamine deficiency and motor symptoms. The blood-brain barrier (BBB) poses a significant challenge in delivering therapeutics to the central nervous system (CNS). In this study, a new nanocopolymer was developed to penetrate the BBB and deliver dopamine to the substantia nigra pars compacta (SNpc) in a Parkinson's-induced rat model. The dopamine loading was 85%, with a release efficiency of 75%. Subsequently, 70 Swiss rats were induced to have Parkinson's using 6-OHD. After 3 days of administration, Parkinson's symptoms emerged and were confirmed by specialists. The induced animals were divided into subgroups based on the dosage of the nanocopolymer (10, 20, or 40 mg for 14 days), after which they were dissected. The brains were sectioned, and the nanocopolymer's penetration was observed and imaged with fluorescence microscopy. Results showed that the nanocopolymer successfully crossed the BBB and the capillary endothelium in the striatum and substantia nigra. Presence of dopamine in the striatum was confirmed by the presence of yellow-green fluorescence in the substantia nigra. Reduced dopamine autoxidation provides sustained delivery of dopamine to the brain. The results also demonstrated the efficacy of this nanocopolymer in penetrating the rat liver, where it affected liver cells significantly more than it did in the brain. The developed nanocopolymer effectively crossed the BBB and elevated dopamine levels in the brain, alleviating motor symptoms in a rat model as an early-stage treatment for Parkinson's disease.