Exacerbation of wood smoke-induced acute lung injury by mechanical ventilation using moderately high tidal volume in mice

We investigated the effects of mechanical ventilation with a moderately high tidal volume (VT) on acute lung injury (ALI) induced by wood smoke inhalation in anesthetized mice. Animals received challenges of air, 30 breaths of smoke (30SM) or 60 breaths of smoke (60SM) and were then ventilated with a VT of 10 ml/kg (10VT) or 16 ml/kg (16VT). After 4-h mechanical ventilation, the bronchoalveolar-capillary permeability, pulmonary infiltration of inflammatory cells, total lung injury score and pulmonary expressions of interleukin-1β and macrophage inflammatory protein-2 mRNA and proteins in the 30SM + 16VT and 60SM + 16VT groups were greater than those in the 30SM + 10VT and 60SM + 10VT groups, respectively. Additionally, the wet/dry weight ratio of lung tissues and lung epithelial cell apoptosis in the 60SM + 16VT group were greater than those in the 60SM + 10VT group. These differences between the 16VT and 10VT groups were not seen in animals with air challenge. Thus, mechanical ventilation with a moderately high VT in mice exacerbates ALI induced by wood smoke inhalation.