Screening Anti-Parkinson’s Disease Drugs in Living Mouse Brains via a Peroxynitrite-Activated Fluorescent Probe

Screening anti-Parkinson's disease (PD) drugs at <i>in vivo</i> brain level is imperative for managing PD yet currently remains unaccomplished. Peroxynitrite (ONOO^-) has been implicated in PD progression. Thus, developing <i>in vivo</i> ONOO^--based imaging tools for anti-PD drug screening holds promise for early prognosis and treatment of PD. Consequently, a near-infrared (NIR) fluorescence probe, <b>BOB-Cl-PN</b>, with high specificity, good sensitivity (LOD = 24 nM), and rapid response (<60 s), was devised to investigate ONOO^- and PD relationships. Utilizing NIR fluorescence imaging, <b>BOB-Cl-PN</b> effectively monitored ONOO^- fluctuations in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD cell models, establishing a cellular high throughput screening (cHTS) system for anti-PD drugs. In live animal imaging, <b>BOB-Cl-PN</b>'s ability to penetrate the blood-brain barrier enabled ONOO^- flux imaging of PD mouse brains. Moreover, <b>BOB-Cl-PN</b> served as an imaging contrast for <i>in vivo</i> screening of potential traditional Chinese medicines for PD therapy, identifying fisetin as having the best therapeutic index among 10 Chinese medicines. This study constructs a sensitive, efficient imaging contrast for monitoring ONOO^- dynamics in PD brains and provides a valuable platform for cellular and <i>in vivo</i> screening of anti-PD drugs.