Engineering a Meso-Carboxyl Rhodamine-Based Fluorogenic Probe for Monitoring Synergistic Drug-Induced Hepatotoxicity in Vivo

Acetaminophen (APAP) is a widely used antipyretic and analgesic drug, yet its hepatotoxic potential upon overdose is well recognized. Beyond overdose, an insidious risk emerges when APAP is co-administered with other drugs for conditions such as tuberculosis or even the common cold. Such drug–drug interactions can synergistically exacerbate hepatotoxicity even at therapeutic doses, posing a major challenge to clinical drug safety. To address this clinical challenge, we developed a novel near-infrared meso-carboxyl-substituted rhodamine platform (RA-COOH) to construct a fluorogenic probe (RA-COO-Leu) for evaluating leucine aminopeptidase (LAP) activity and monitoring synergistic drug-induced hepatotoxicity. The probe exhibits a rapid (< 10 min) and sensitive response toward LAP both in solution and in living cells. Importantly, RA-COO-Leu not only visualized drug-induced liver injury caused by APAP overdose, but also, revealed that isoniazid (INH) pre-treatment markedly potentiates APAP-induced hepatotoxicity in vivo. Collectively, this study provides a powerful molecular tool for LAP detection and a versatile research platform that can be utilized to elucidate the mechanisms and identify drugs with potential risks for synergistic hepatotoxicity.