Digoxin attenuates LPS-induced acute lung injury in mice via NF-κB and HIF-1α inhibition

Acute lung injury (ALI), which can progress to the highly lethal acute respiratory distress syndrome (ARDS), remains a condition with limited pharmacological interventions, highlighting the urgent need for mechanism-informed repurposing strategies. Given the reported inhibitory effects of digoxin on nuclear factor kappa B (NF-κB)-mediated inflammation, we assessed its prophylactic and therapeutic efficacy in a murine model of lipopolysaccharide (LPS)-induced ALI. Sixty-six adult male BALB/c mice were divided into control and LPS-challenged groups. The LPS group (5 mg/kg, intratracheal) was assigned to either prophylactic regimens (daily saline, dexamethasone 5 mg/kg, or digoxin 1 mg/kg, administered intraperitoneally for 5 days prior to LPS) or therapeutic regimens (same interventions initiated 12 h post-LPS for 3 days). At the study endpoint, pulmonary edema (wet-to-dry ratio) and lung injury pathways were analyzed in lung homogenates, including tumor necrosis factor-alpha (TNF-α), IL-6, myeloperoxidase (MPO), malondialdehyde (MDA), NF-κB (p65) DNA-binding activity, C-X-C motif chemokine ligand 2/macrophage inflammatory protein-2 (CXCL2/MIP-2), and hypoxia-inducible factor-1 alpha (HIF-1α), alongside histopathological evaluations. Digoxin significantly reduced pulmonary edema in the therapeutic group (p = 0.02) and decreased TNF-α levels (p = 0.014), while robustly suppressing IL-6 and MDA in both prophylactic and therapeutic settings (each p < 0.001). Moreover, digoxin lowered MPO levels prophylactically (p = 0.007) and therapeutically (p = 0.014). It also strongly inhibited NF-κB activation, reducing CXCL2/MIP-2, while decreasing HIF-1α in both regimens (each p < 0.001). Histological analysis corroborated these findings, revealing improved alveolar architecture and reduced inflammatory injury. In conclusion, digoxin exhibits potent immunomodulatory activity in experimental ALI, warranting further translational research focused on dose optimization and safety profiling.