Imaging and Quantitative Analysis of the Interstitial Space in the Caudate Nucleus in a Rotenone-Induced Rat Model of Parkinson’s Disease Using Tracer-based MRI

Parkinson’s disease (PD) is characterized by pathological changes within several deep structures of the brain, including the substantia nigra and caudate nucleus. However, changes in interstitial fluid (ISF) flow and the microstructure of the interstitial space (ISS) in the caudate nucleus in PD have not been reported. In this study, we used tracer-based magnetic resonance imaging (MRI) to quantitatively investigate the alterations in ISS and visualize ISF flow in the caudate nucleus in a rotenone-induced rat model of PD treated with and without madopar. In the rotenone-induced rat model, the ISF flow was slowed and the tortuosity of the ISS was significantly decreased. Administration of madopar partially prevented these changes of ISS and ISF. Therefore, our data suggest that tracer-based MRI can be used to monitor the parameters related to ISF flow and ISS microstructure. It is a promising technique to investigate the microstructure and functional changes in the deep brain regions of PD.