The cyclic hexapeptide AcF attenuates sepsis-induced acute lung injury and mortality in rats.

OBJECTIVE The purpose of this study was to elucidate the possible beneficial effects of AcF on acute lung injury (ALI) in a rat model of sepsis. MATERIALS AND METHODS Male Sprague-Dawley rats were randomly divided into the following four experimental groups (n = 10 per group): animals undergoing a sham cecal ligature puncture (CLP) (Sham group); animals undergoing CLP (control group); or animals undergoing CLP and treated with saline (Saline group) and animals undergoing CLP and treated with AcF (AcF group). At 24 h after CLP, blood, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The lung wet/dry weight ratio, Protein concentration and the count of inflammatory cells or neutrophils in the BALF were determined. The pathologic changes in lungs were examined with the optical microscopy. Myeloperoxidase (MPO) activity, the expression of inflammatory cytokines were measured in lung tissue and BALF respectively. Survival rates were recorded at 120h in the four groups in another experiment. RESULTS Histology findings revealed acute lung injury in rats in the CLP group, whereas those in the AcF-treated group had mild lung injury. Treatment with AcF significantly attenuated the CLP-induced pulmonary edema and inflammation, as it significantly decreased lung wet/dry ration, protein concentration and the infiltration of inflammatory cells and neutrophils in the lung tissues. In addition, the secretion of inflammatory cytokines, such as TNF-α, IL-6, IL-1b and macrophage inflammatory protein-2 (MIP-2) was decreased in AcF treated group compared with the control saline treated group. CONCLUSIONS AcF administration ameliorates acute lung injury in a rat model of sepsis induced by CLP. AcF can be developed as a novel treatment for severe sepsis-induced ALI.