Evaluation of a boronate-masked naphthalimide probe for peroxynitrite-responsive fluorescence imaging in experimental acute liver injury.

Abstract

Peroxynitrite (ONOO-), a key mediator of oxidative and nitrosative stress, participates extensively in the pathological progression of acute liver injury and cancer. Because aberrant ONOO- production is closely associated with these conditions, accurate analysis of this short-lived species is important for early diagnosis and for evaluating therapeutic responses. Real-time monitoring of ONOO- in representative disease models is therefore valuable for identifying pathophysiological changes before irreversible tissue damage occurs. Fluorescence imaging provides a highly sensitive, noninvasive, convenient, and selective means of detecting and visualizing ONOO-in situ within complex biological systems. Here, we developed HD-ONOO, a lysosome-associated fluorescent probe constructed on a naphthalimide scaffold, for ONOO--responsive fluorescence measurements and exploratory biological imaging. The probe responded to added ONOO- and showed a low background signal under the tested conditions. Cellular fluorescence experiments demonstrated that HD-ONOO reported fluorescence changes following oxidant exposure and pharmacological modulation in living LX-2 cells. Its biological applicability was further established by whole-animal and tissue-section imaging, which revealed treatment-associated fluorescence in hepatic samples. In particular, the probe reported fluorescence differences in two chemically induced models of acute liver injury and produced trends consistent with organ imaging and serum biochemical indices. This study evaluates an established boronate-based design in experimental liver-injury settings; the fluorescence readout alone does not establish oxidant identity or absolute ONOO- concentrations. HD-ONOO may provide an exploratory imaging reagent for studies of hepatic redox responses, subject to direct product identification and further analytical validation.