Endothelial Colony-forming Cells Attenuate Ventilator-induced Lung Injury in Rats with Acute Respiratory Distress Syndrome

Abstract

Mechanical ventilation (MV) can cause ventilator-induced lung injury (VILI). This study investigated whether endothelial colony-forming cells (ECFC) could inhibit VILI in a rat model of acute respiratory distress syndrome (ARDS). Male Wistar rats received the femoral artery and venous cannulation (sham group) or were injected intravenously with 500μg/kg lipopolysaccharide to induce ARDS. The ARDS rats were subjected to MV. Immediately after the MV, the rats were randomized and injected intravenously with vehicle (ARDS group) or ECFC (ECFC group, n=8 per group). The oxygen index, lung wet-to-dry weight (W/D) ratios, cytokine protein levels in serum or bronchoalveolar lavage fluid (BALF), neutrophil counts, neutrophil elastase and total protein levels in BALF, histology and cell apoptosis in the lung were detected. The protein levels of endothelin-1, inducible nitric oxide synthase (iNOS), endothelial NOS, matrix metalloproteinase (MMP)-9, Bax, Bcl-2, gelsolin, cleaved caspase-3, phosphorylated NF-κBp65 and myosin light chain (MLC) in the lung were analyzed. Compared with the ARDS group, treatment with ECFC significantly increased the oxygen index, and decreased the lung W/D ratios and injury, and the numbers of apoptotic cells in the lungs, neutrophils counts, total protein and elastase concentrations in BALF of rats. ECFC treatment significantly minimized the protein levels of pro-inflammatory cytokines in BALF and serum, but increased interleukin 10 in rats. Furthermore, ECFC treatment significantly reduced the protein levels of endothelin-1, iNOS, Bax, Gelsolin, MMP-9, cleaved caspase-3, phosphorylated NF-κBp65 and MLC, but enhanced eNOS and Bcl-2 in the lungs of rats. Therefore, ECFC attenuated inflammation, cell apoptosis and VILI in ARDS rats.