A novel fluorescent probe for in vivo H₂S monitoring in inflammatory arthritis.

Hydrogen sulfide (H₂S), a crucial gaseous signaling molecule, plays a pivotal regulatory role in various physiological and pathological processes. In this study, we successfully developed a novel H₂S fluorescent probe NR based on the Nile red fluorophore. The probe achieves specific recognition of H₂S through an isothiocyanate functional group, and its recognition mechanism was confirmed by high-resolution mass spectrometry. Probe NR exhibits excellent stability and high sensitivity, with a detection limit of 3.66 μM. Demonstrating low cytotoxicity and suitability for physiological pH conditions, probe NR has been successfully applied for real-time monitoring of H₂S in vivo. In an LPS-induced arthritis model in nude mice, probe NR effectively enabled dynamic monitoring of H₂S levels at inflammatory sites. The successful development of this probe provides a powerful tool for investigating the pathophysiological mechanisms of H₂S in inflammatory diseases, demonstrating promising potential for disease diagnosis and therapeutic monitoring.