Liposomal Piceatannol Mitigates Methotrexate-Induced Oxidative Renal Injury via Modulation of Nrf2/HO-1, TLR4/NF-κB, MAPK, and Apoptotic Pathways in Rats

Methotrexate (MTX) is a widely used chemotherapeutic and immunosuppressive agent, but its clinical utility is limited by oxidative stress-mediated renal toxicity. This study evaluated the nephroprotective potential of the dietary polyphenolic bioactive molecule piceatannol (PIC) in its crude and liposomal nanoparticle (PIC-LNP) forms against MTX-induced kidney injury in rats. Sixty rats were allocated into six groups and received vehicle, PIC, PIC-LNPs, MTX, or combinations of MTX with PIC or PIC-LNPs. MTX administration induced marked renal dysfunction and oxidative/nitrosative stress, reflected by elevated serum urea, creatinine, and uric acid, together with increased renal ROS, MDA, protein carbonyls, 8-OHdG, and nitric oxide, in parallel with suppression of the Nrf2/HO-1 antioxidant pathway. These disturbances were accompanied by activation of TLR4/NF-κB and MAPK signaling, upregulation of pro-inflammatory cytokines, and a shift toward apoptosis, as evidenced by increased Bax and caspase-3 and reduced Bcl-2 expression. Histological and ultrastructural analyses confirmed extensive glomerular and tubular damage with mitochondrial disruption and cytoplasmic vacuolations. PIC treatment attenuated these MTX-induced alterations, whereas the liposomal formulation conferred superior protection. PIC-LNPs restored Nrf2/HO-1 signaling, enhanced endogenous antioxidant defenses, reduced oxidative/nitrosative and inflammatory responses, and normalized apoptotic markers, accompanied by substantial preservation of renal architecture and cellular integrity. Immunohistochemistry demonstrated strong Nrf2 expression with minimal NF-κB activation in the PIC-LNP group. Collectively, these findings highlight liposomal piceatannol as a promising bioactive-molecule-based strategy for controlling oxidative stress and mitigating chemotherapy-associated oxidative-stress-related renal injury.