Metabolic analysis of striatal tissues from Parkinson's disease-like rats by electrospray ionization ion mobility mass spectrometry.

Electrospray ionization ion mobility mass spectrometry (ESI-IMMS) was used to study the striatal metabolomes in a Parkinson's like disease (PD-like) rat model. Striatal tissue samples from Berlin Druckrey IV (BD-IV) with PD-like disease 20 dpn-affected and 15 dpn-affected rats (dpn: days postnatal) were investigated and compared with age-matched controls. An ion mobility mass spectrometer (IMMS) produced multidimensional spectra with mass to charge ratio (m/z), ion mobility drift time, and intensity information for each individual metabolite. Principle component analysis (PCA) was applied in this study for pattern recognition and significant metabolites selection (68% data was modeled in PCA). Both IMMS spectra and PCA results showed that there were clear global metabolic differences between PD-like samples and healthy controls. Nine metabolites were selected by PCA and identified as potential biomarkers using the Human Metabolome Database (HMDB). One targeted metabolite in this study was dopamine. Selected-mass mobility analysis indicated the absence of dopamine in PD-like striatal metabolomes. A major discovery of this work, however, was the existence of an isomer of dopamine. By using ion mobility spectrometry, the dopamine isomer, which has not previously been reported, was separated from dopamine.