Protective effect of hemopexin on systemic inflammation and acute lung injury in an endotoxemia model.

BACKGROUND

Hemopexin (HPX) has been identified as an anti-inflammatory agent, but its role in endotoxemia is unclear. The purpose of this study was to determine whether HPX suppresses systemic and lung inflammation in a mouse model of endotoxemia.

MATERIALS AND METHODS

At 30 min of intraperitoneal administration of lipopolysaccharide (LPS; 10 mg/kg), either distilled water (LPS-only treated animals) or HPX (5 mg/kg) was injected into mice via the tail vein, and the survival rates were analyzed after 36 h. Furthermore, the serum levels of tumor necrosis factor-α, interleukin-6 (IL-6), and HPX were determined at 0, 3, and 6 h, and the expression levels and DNA binding activities of phosphorylated cytoplasmic inhibitor κB-α, nuclear factor-κB (NF-κB), and the p65 subunit of NF-κB were evaluated and compared with the rates of histologic lung injury after 6 h.

RESULTS

Serum tumor necrosis factor-α and interleukin-6 levels were decreased in HPX-treated animals at 3 and 6 h (P < 0.05). HPX suppressed the NF-κB pathway (P < 0.05) and reduced acute lung injury at 6 h, and 36 h after initial treatment, the survival rate was higher in HPX-treated animals than that in LPS-treated animals (P < 0.05).

CONCLUSIONS

HPX downregulated proinflammatory cytokine production and acute lung injury as well as improved survival rates in a mouse model of endotoxemia. These effects were associated with HPX-mediated suppression of the NF-κB pathway.