(2010). One or five days following saline or P. berghei administration, mice were sedated (diazepam, 1 mg UMI-77 clinical trial i.p.), anaesthetised (sodium thiopental, 20 mg/kg i.p.), tracheotomised, paralysed (vecuronium bromide, 0.005 mg kg−1 i.v.), and mechanically ventilated with a constant flow ventilator (Samay VR15; Universidad de la Republica, Montevideo, Uruguay) using the following settings: respiratory rate = 100 breaths/min, tidal volume (VT) = 0.2 ml, and fraction of inspired oxygen (FiO2) = 0.21. The anterior chest wall was

surgically removed, and a positive end-expiratory pressure (PEEP) of 2 cmH2O was applied. After a 10-min ventilation period, lung mechanics were computed. Airflow and tracheal pressure (Ptr) were measured ( Burburan et al., 2007). In an open chest preparation, Ptr reflects transpulmonary pressure (PL). Lung resistive (ΔP1) and viscoelastic/inhomogeneous (ΔP2) pressures, as well as static elastance (Est), were computed by the end-inflation occlusion method ( Bates et al., 1988). Lung Selleck SCR7 mechanics measurements were performed 10 times in each animal. All data were analysed using

the ANADAT data analysis software (RHT-InfoData, Inc., Montreal, Quebec, Canada). Laparotomy was performed immediately after determination of lung mechanics, and heparin (1000 IU) was injected into the vena cava. The trachea was clamped at end-expiration (PEEP = 2 cmH2O), and the abdominal aorta and vena cava were sectioned, producing massive haemorrhage and rapid death. The right lung was then removed, fixed in 4% buffered formaldehyde and embedded in paraffin. Slices (thickness = 4 μm) were cut and stained with haematoxylin and eosin. Lung morphometric analysis was performed using an integrating eyepiece with a coherent system consisting of a grid with 100 points and 50 lines (known length) coupled to a conventional light microscope (Olympus BX51, Olympus Latin America, Inc., Brazil). The volume fractions of the lung occupied by collapsed

alveoli and normal pulmonary areas were determined by the point-counting technique (Weibel, 1990) at a magnification of 200× across 10 random, non-coincident microscopic fields. Neutrophils Thiamet G and mononuclear (MN) cells and lung tissue were evaluated at 1000× magnification. Points falling on neutrophils and MN cells were counted and divided by the total number of points falling on lung tissue in each field of view. For quantification of interstitial oedema, 10 arteries were transversely sectioned. The number of points falling on areas of perivascular oedema and the number of intercepts between the lines of the integrating eyepiece and the basement membrane of the vessels were counted at a magnification of 400×. The interstitial perivascular oedema index was calculated as follows: number of points/number of intercepts (Hizume et al., 2007). At days 1 and 5, the W/D ratio was determined in a separate group of mice (n = 6/group), which was subjected to an identical protocol to the one described above.