Icariin prevents acute high-altitude pulmonary edema in rats by alleviating oxidative stress and modulating cuproptosis-related proteins

This study aimed to evaluate the therapeutic efficacy and underlying mechanisms of ICA in AHAPE. Rats were exposed to a hypobaric hypoxic chamber simulating an altitude of 6000 m (ascent rate: 10 m/s, pressure: 47.3 kPa, O2 concentration: 9.9%) for 3 days to induce AHAPE. To prevent AHAPE, rats were pretreated with ICA (30, 60, or 120 mg/kg/day) or acetazolamide (100 mg/kg/day) for 7 consecutive days before exposure. The same dosages were continued throughout the 3-day hypobaric hypoxic exposure period. The mechanisms underlying ICA’s effects were investigated using 4D label-free quantitative proteomics. Immunohistochemistry, Western blotting (WB), and transmission electron microscopy were conducted to verify the proteomic results. Rats with AHAPE exhibited significant body weight loss, elevated counts of white blood cells, lymphocytes, neutrophils, and increased hemoglobin levels. Additionally, increased pulmonary vascular permeability, higher lung water content, severe histopathological damage, and elevated ALT activity were observed. ICA administration ameliorated these changes in a dose-dependent manner, with the most pronounced effects at a dosage of 120 mg/kg. ICA significantly increased glutathione S-transferase Mu 5 (GSTM5) expression, reduced ferredoxin 1 (FDX1) expression, and reversed hypoxia-induced copper transporter 1 (CTR1) subcellular redistribution, effectively reversing copper ion accumulation in lung tissue. Proteomic analysis identified 89 core differentially expressed proteins. Mechanistically, ICA alleviated pulmonary edema and tissue injury primarily by restoring mitochondrial function through the regulation of glutathione metabolism, oxidative stress (OS), and the cuproptosis pathway. ICA effectively prevents and treats AHAPE. Its protective mechanisms involve antioxidant effects, regulation of copper homeostasis, and modulation of cuproptosis-related protein expression, which subsequently attenuates the inflammatory and oxidative stress cascade. These findings provide crucial experimental evidence for developing targeted therapeutic approaches against AHAPE.