A carotid artery catheter was placed for blood pressure monitoring and infusion of NaCl 0.9% containing 100 mmol/l HCO3- (350 ��l/h). There was no additional fluid support in any conducted experiment. A urinary catheter was inserted. VT, RR, airway pressure, peripheral oxygen saturation and urine output were monitored (Pulmodyn, Hugo-Sachs-Electronics, March-Hugstetten, Germany; MouseOx, STARR Life-Sciences, Oakmont, PA, USA). After preparation, a recruitment maneuver was performed (airway pressure 35 cmH2O for 5 sec) before respirator settings were adjusted for 6 h to VT 12 ml/kg, RR 120 minute-1, PEEP 2 cmH2O. All mice survived the protocol. At termination of the experiments mice were sacrificed by exsanguination via the carotid catheter. Non-ventilated mice served as controls.Simvastatin treatmentSimvastatin (Sigma, Steinheim, Germany) was dissolved in ethanol and diluted with saline. Mice received i.p. injections of 20 mg/kg simvastatin or solvent 24 h and 1 h before the VILI experiment. Non-ventilated mice were treated in according intervals. Simvastatin treatment had no impact on overall cholesterol, HDL and LDL cholesterol in studied mice.Blood gas analysesBlood samples were analyzed for paO2, paCO2, ph, HCO3-, SBE, Lactate, Na+, K+, Cl-, Ca2+ by blood gas analyzer (ABL-800, Radiometer, Copenhagen, Denmark). P/F ratio was calculated as paO2 /FiO2.Lung permeabilityHuman-Serum-Albumin (HSA; 1 mg) was injected via carotid artery catheter or tail vein in ventilated or non-ventilated mice, respectively, 90 minutes before the experiment termination. Mice were sacrificed and bronchoalveolar lavage (BAL) of the right lung was performed with 2 �� 400 ��l saline. BAL- and plasma HSA-levels were quantified by ELISA (enzyme-linked immuno sorbent assay) (Bethyl (biomol), Hamburg, Germany). Permeability was assessed by calculating the HSA BAL/plasma ratio.Electron microscopyLungs were flushed via the pulmonary artery, cut, immersion-fixed (1.5% glutaraldehyde, 1.5% paraformaldehyde in 0.15 M HEPES), rinsed (0.1 mmol/l HEPES, 0.1 mmol/l cacodylate buffer) and osmicated (1% osmium tetroxide in 0.1 mmol/l cacodylate buffer). After rinsing in 0.1 mmol/l cacodylate buffer and distilled water, specimens were stained in half-saturated aqueous uranylacetate solution (1:1). Samples were dehydrated in ascending acetone concentrations, embedded in epon, cut (70 nm), stained with lead citrate and uranyl-acetate, and analyzed.Differential cell count lungLungs were flushed. The left lung was digested in RPMI containing Collagenase and DNAse for 1 h.