ABSTRACT
Objective:To evaluate the effects of GSK484 on ventilator-induced lung injury (VILI) and neutrophil extracelluar traps (NETs) in mice.Methods:Forty-eight SPF healthy male C57BL/6 mice, aged 5-6 weeks, weighing 15-20 g, were divided into 4 groups ( n=12 each) by a random number table method: spontaneous breathing group (group S), spontaneous breathing+ GSK484 intervention group (group SG), VILI group (group V), and VILI + GSK484 intervention group (group VG). The animals kept spontaneous breathing for 4 h after tracheal intubation in S and SG groups. The animals were mechanically ventilated for 4 h (tidal volume 30 ml/kg, respiratory rate 75 breaths/min, inspiratory/expiratory ratio 1∶2, positive end-expiratory pressure 0 mmHg, fraction of inspired oxygen 21%) in V and VG groups. At 3 days before developing the VILI model, GSK484 4 mg/kg was intraperitoneally injected once a day in SG and VG groups, while the equal volume of normal saline was given instead in S and V groups. Blood samples were collected from the abdominal aorta for blood gas analysis at 4 h of spontaneous breathing or mechanical ventilation, and PaO 2 was recorded. The mice were then sacrificed and bronchoalveolar lavage fluid (BALF) was collected and lung tissues were obtained for microscopic examination of the pathological changes (with a light microscope after HE staining) which were scored and for determination of wet to dry weight ratio (W/D ratio), concentrations of interleukin-1beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α) and myeloperoxidase (MPO) in BALF (by enzyme-linked immunosorbent assay), expression of peptidylarginine deiminase 4 (PAD4), neutrophil elastase (NE), high mobility group box 1 (HMGB1) and citrullinated-histone 3 (Cit-H3) in lung tissues (by Western blot). Results:Compared with S and SG groups, the lung injury score and W/D ratio were significantly increased, PaO 2 was decreased, concentrations of IL-1β, IL-6, TNF-α and MPO in BALF were increased, and the expression of PAD4, NE, HMGB1 and Cit-H3 in lung tissues was up-regulated in V and VG groups ( P<0.05). Compared with group V, the lung injury score and W/D ratio were significantly decreased, PaO 2 was increased, the concentrations of IL-1β, IL-6, TNF-α and MPO in BALF were decreased, and the expression of PAD4, NE, HMGB1 and Cit-H3 was down-regulated in group VG ( P<0.05). Conclusions:GSK484 can alleviate VILI in mice, and the mechanism is associated with inhibition of PAD4, reduction of the production of NETs and attenuation of inflammatory responses in lung tissues.