OBJECTIVETo investigate the role of interleukin-17 (IL-17) in alveolar fluid clearance in mice with acute lung injury (ALI) and explore the possible mechanism.

METHODSSixteen IL-17-knockout mice and 16 wild-type mice were both randomized for intratracheal instillation of PBS (control) on lipopolysaccharide (LPS) to induce ALI. Forty-eight hours after the treatments, the wet-dry ratio (W/D) of the lungs, IL-8 in the bronchoalveolar lavage fluid (BALF) and histopathological changes of the lung tissues were examined. The expressions of epithelial sodium channel α subunit (α-ENaC) was detected with Western blotting and liver kinase B1 (LKB1) was detected with immunohistochemistry.

RESULTSCompared with wild-type mice treated with LPS, IL-17 knockout mice showed significantly decreased W/D of the lungs (9.739∓3.3 vs 5.351∓0.56) and IL-8 level in the BALF (67.50∓7.33 vs 41.00∓3.16 pg/mL) following LPS challenge. Pathological examination revealed reduced alveolar edema fluid aggregations and lower lung injury score in IL-17 knockout mice with also higher expression levels of ENaC and LKB1 compared with the wild-type mice.

CONCLUSIONKnocking out IL-17 in mice not only alleviates inflammation of the lung tissue following ALI but also reduces the loss of ENaC protein and promotes alveolar fluid clearance, mechanism of which is probably associated with LKB1.