Metabolic Syndrome-Associated Pulmonary Lipid and Iron Accumulation and Alterations in TLR4/NF-κB Signaling and Ferroptosis-Regulatory Proteins Are Attenuated by Resveratrol Plus Quercetin in Rats.

Metabolic syndrome (MetS) is associated with ectopic fat deposition, chronic systemic inflammation, oxidative stress, and increased susceptibility to organ dysfunction. While its cardiovascular consequences have been extensively studied, pulmonary al-terations remain less well characterized, particularly with respect to ferropto-sis-regulatory pathways. In this study, we evaluated ectopic fat deposition, TLR4/NF-κB signaling pathway, and ferroptosis-regulatory markers in a MetS rat model and analyzed the therapeutic potential of combined resveratrol plus quercetin (combined R + Q) supplementation. Rats were maintained for five months with 30% sucrose in drinking water to induce MetS and subsequently treated for 4 weeks with the R + Q combination (50 and 0.95 mg/kg/day, respectively). Lung tissue was analyzed by fluorescence microscopy to assess fat deposition, by colorimetric histology to evaluate hemosiderin-containing cells, including the quantification of hemosiderin-laden macrophages (HLMs), and by immunoblotting to determine TLR4, p-p65, and glutathione peroxidase 4 (GPX4), as well as cystine/glutamate antiporter SLC7A11 (xCT) protein expression. Lungs from MetS rats exhibited significantly higher fat deposits, pathological HLMs accumulation, upregulated TLR4/p-p65 signaling, elevated compensatory GPX4 expression, and depressed xCT levels compared with controls. Notably, the combined R + Q treatment markedly attenuated alterations in TLR4/NF-κB signaling and successfully restored xCT expression (p = 0.0116), stabilizing pulmonary redox homeostasis and limiting overall tissue susceptibility to lipotoxic injury.