Detection of hypochlorous acid fluctuation via a near-infrared fluorescent probe in Parkinson's disease cells and mouse models.

Parkinson's disease (PD) is a neurodegenerative disorder caused by excessive reactive halogen species leading to the death of dopaminergic (DA) neurons, which disrupts the coordination of normal physiological structures and functions. Hypochlorous acid (HOCl) is a reactive halogen species whose overproduction is associated with the death of DA neurons. Herein, overproduction of HOCl may be a neurotoxin substance in the pathogenesis of PD. Therefore, it is essential to understand the disease of HOCl in PD model. However, early detection HOCl in PD model remains lacking of effective methods. In this study, a high sensitivity off-on near-infrared probe (MB-HOCl) was designed and synthesized. MB-HOCl showed a quantitative response toward HOCl (0-100 μM) with detection limit of 0.32 μM. Importantly, MB-HOCl was capable of selectively and specially detecting exogenous and endogenous HOCl in PC-12 cells and was successfully used for imaging in PD mice models. All results demonstrate that the probe (MB-HOCl) holds great promise for understanding the disease and diagnosis of HOCl-mediated PD models.