Protective Role of Boldine Against 5‐Fluorouracil‐Induced Nephrotoxicity: In Vitro and In Vivo Approach

Drug‐induced nephrotoxicity is a significant clinical complication associated with several chemotherapeutic agents, including 5‐fluorouracil (5‐FU). This study was aimed to investigate the nephroprotective potential of boldine, an aporphine alkaloid, against 5‐FU‐induced renal toxicity using in vitro (HEK293 cells) and in vivo (Wistar rats) models. In vitro cytotoxicity was evaluated using the MTT assay, AO/EB and DAPI staining was performed to identify apoptotic alterations. The expression of apoptotic and antioxidant genes was analyzed by quantitative and semi‐quantitative PCR. For the in vivo study, rats were divided into five groups. One group received a single intraperitoneal dose of 5‐FU (150 mg/kg) to induce nephrotoxicity. In the remaining groups, 5‐FU was administered followed by oral treatment with boldine (10 or 20 mg/kg) or silymarin (100 mg/kg) for 7 days. Biochemical markers including creatinine, urea, blood urea nitrogen, uric acid in serum and oxidative stress indicators in kidney tissue were analyzed. MAPK pathway‐related gene expression and histopathological changes were assessed. Treatment of HEK cells with 5‐FU markedly reduced cell viability and induced apoptosis, while co‐treatment with boldine restored viability and normal cell morphology. Boldine modulated the 5‐FU‐induced downregulation of SOD, CAT, GPx, and Bcl‐2 and upregulation of Bax and caspase‐3. In vivo, boldine treatment normalized elevated nephrotoxic markers in serum, enhanced antioxidant enzyme activities, and inhibited activation of ASK1, ERK1, c‐Jun, and NF‐κB1. Histopathological findings further confirmed that boldine preserved renal tissue integrity and prevented tubular and glomerular damage. Overall, boldine significantly protected against 5‐FU‐induced renal injury via anti‐apoptotic, antioxidant, and anti‐inflammatory mechanisms.