Dual-channel fluorescence imaging of arginase/peroxynitrite imbalance in metabolic inflammation-related macrophage models and diabetic liver tissues.

Macrophage dysfunction is closely associated with metabolic inflammation, involving arginase-related arginine metabolic dysregulation and peroxynitrite (ONOO-)-mediated oxidative/nitrative stress. Herein, a dual-channel fluorescence imaging platform comprising Arg-Blue and ONOO--Green was developed to visualize the relative imbalance between arginase-associated and ONOO--responsive signals. Arg-Blue exhibited blue fluorescence activation upon interaction with arginase through binding-induced restriction of intramolecular motion, whereas ONOO--Green showed a selective turn-on green fluorescence response toward ONOO-. Their well-separated emission channels allowed simultaneous visualization of the two signals in metabolically inflamed macrophages. Lipopolysaccharide, oxidized low-density lipoprotein, and high-glucose/LPS stimulation produced decreased Arg-Blue fluorescence and enhanced ONOO--Green fluorescence, resulting in an increased green/blue ratio. Treatment with ginsenoside compound K or N-acetyl-L-cysteine partially restored this fluorescence imbalance. The dual-probe system was further applied to ex vivo liver tissues from streptozotocin-induced diabetic mice, where enhanced ONOO--responsive fluorescence and an elevated green/blue ratio were observed. These results demonstrate a practical dual-channel strategy for visualizing arginase-associated/ONOO--responsive imbalance in metabolic inflammation-related macrophage models and diabetic liver tissues.