Background
Oxidation and inflammation caused by lower limb ischemia-reperfusion (I/R) readily induce lung injury. We elucidated whether cepharanthine, a potent antioxidative and anti-inflammatory drug, can mitigate lung injury induced by lower limb I/R. Role of heme oxygenase 1 (HO-1) was also investigated. Materials and
Conclusions
Cepharanthine mitigates lung injury induced by bilateral lower limb I/R in rats. The mechanisms may involve its effects on reducing oxidation and inflammation. The mechanisms may also involve enhancing HO-1 expression.
Methods
Adult male Sprague-Dawley rats were randomized to receive I/R, I/R plus cepharanthine, or I/R plus cepharanthine plus the HO-1 activity inhibitor tin protoporphyrin (SnPP; n = 12 in each group). Sham control groups were run simultaneously. I/R was induced by applying rubber band tourniquets high around each thigh for 3 h followed by reperfusion for 24 h.
Results
Rats receiving I/R had significant increases in concentrations of nitric oxide, malondialdehyde (lipid peroxidation marker), and inflammatory molecules (including interleukin 6, macrophage inflammatory protein 2, and prostaglandin E2) in plasma, and the lungs, indicating that I/R caused significant oxidation and inflammation in rats. Rats receiving I/R also had significant increases in concentration of phosphorylated inhibitor-κB, indicating that I/R caused significant nuclear factor κB activation. Assays of arterial blood gas, biochemistry, and histopathology confirmed that I/R-induced significant lung injury in rats. Cepharanthine significantly reduced the oxidation, inflammation, nuclear factor κB activation, and lung injury induced by I/R. Of note, cepharanthine significantly enhanced pulmonary HO-1 expression after I/R. Moreover, these previously mentioned effects of cepharanthine were partially reversed by inhibiting the activity of HO-1. Conclusions: Cepharanthine mitigates lung injury induced by bilateral lower limb I/R in rats. The mechanisms may involve its effects on reducing oxidation and inflammation. The mechanisms may also involve enhancing HO-1 expression.