Abstract: Objective To explore the mechanism underlying the protective effect of sevoflurane against ventilator-induced lung injury (VILI). Methods Thirty-two SD rats were randomized into mechanical ventilation (MV) group, MV+sevoflurane group (MS group), MV+sevoflurane+ transient receptor potential vanillate subtype 4 (TRPV4) agonist group (MST group) and MV+ sevoflurane + vehicle group (MSV group). Arachidonic acid (AA) in the lung tissues was quantified with ELISA. TRPV4, cytoplasmic phospholipase A2 (C-PLA2) and myosin light chain kinase (MLCK) protein expressions were detected by Western blotting. Lung injury in the rats was evaluated by assessing MLCK protein expression level, pulmonary permeability index, lung wet/dry ratio, leukocyte count in the bronchoalveolar lavage fluid (BALF), myeloperoxidase content in lung tissue, and histological score of the lungs. Results The rats in MV group showed significantly increased TRPV4 and C-PLA2 expression levels in the lung tissues with increased lung permeability and obvious lung inflammation compared with those in the other 3 groups (P<0.05). No significant differences were found in the parameters associated with lung injuries between MS group and MSV group. Compared with those in MST group, the rats in MS group and MSV group showed significantly reduced AA production and TRPV4 and C-PLA2 expressions in the lungs (P<0.05) with alleviated lung hyper-permeability and inflammation (P<0.05). Conclusion Sevoflurane protects against VILI in rats by down-regulating the TRPV4/C-PLA2 signaling pathway.

Key words: mechanical ventilation; ventilator-induced lung injury; sevoflurane; transient receptor potential vanillate subtype 4; cytoplasmic phospholipase A2