Low molecular weight heparin may prevent acute lung injury induced by sepsis in rats

• LMWH decreased the expression of TNF-α, IL-1β, HMGB1 and ICAM-1 in the lungs of ALI rats.
• Treatment with LMWH markedly reduced the enhanced lung permeability.
• LMWH administration inhibited the nuclear translocation of NF-κB in the lungs.

The purpose of this study was to assess the protective effect of low molecular weight heparin (LMWH) on acute lung injury (ALI) in rats induced by sepsis. Rat ALI model was reproduced by cecal ligation and puncture (CLP). All rats were randomly divided into three groups (n = 50): control group (A), ALI group (B), and LMWH-treated group (C). Group A received a sham operation and the other groups underwent CLP operation. Groups A and B accepted intraperitoneal injection (i.p.) of normal saline (NS) at a dose of 2.0 ml kg− 1 and ceftriaxone (30 mg kg− 1), group C was intraperitoneally injected with additional LMWH (150 U kg− 1) except saline and ceftriaxone. Blood was collected and lung tissue was harvested at the designated time points for analysis. The lung specimens were harvested for morphological studies, immunohistochemistry examination. Lung tissue edema was evaluated by tissue water content. The levels of lung tissue myeloperoxidase (MPO) were determined. Meanwhile, the nuclear factor-kappa B (NF-κB) activation, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) levels, high mobility group box 1 (HMGB1) and intercellular adhesion molecule-1 (ICAM-1) protein levels in the lung were studied. There was a significant difference in each index between groups A and B (P < 0.05). Treatment with LMWH significantly decreased the expression of TNF-α, IL-1β, HMGB1 and ICAM-1 in the lungs of ALI rats. Similarly, treatment with LMWH dramatically diminished sepsis-induced neutrophil sequestration and markedly reduced the enhanced lung permeability. In the present study, LMWH administration inhibited the nuclear translocation of NF-κB in the lungs. These data suggest that LMWH attenuates inflammation and ameliorates lung pathology in CLP-induced sepsis in a rat model.