Acute lung injury model induced by single dose of paraquat intratracheal aerosolization in mice

Objective To establish a mouse model of acute lung injury (ALI) via intratracheal aerosolization of paraquat (PQ). Methods Thirty male C57BL/6J mice of 8-10 weeks old were randomly(random number) divided into the paraquat model group (n = 15) and the saline control group (n = 15). Mice in the paraquat model group were administered PQ solution (0.4 mg/mL) at a single dose of 50 μL per mouse via intratracheal aerosolization. Mice in the saline control group received an equal volume of saline. Mice were sacrificed 72 h post-PQ administration and samples were collected. The general physical condition of mice including body weight as well as mortality was monitored daily. Pulmonary function, cell counting and classification of bronchoalveolar lavage fluid (BALF), proinflammatory cytokines (TNF-α, IL-1β, and IL-6) levels of BALF and serum, MPO activity and total protein concentration of BALF and pathological lung injury scores were obtained. Results The body mass of mice decreased progressively within 72 h after PQ intratracheal administration. The static compliance of lung decreased (P<0.01) and the resistance increased (P<0.01). The number of inflammatory cells in BALF was significantly higher than that of the saline control group (all P<0.01), the levels of proinflammatory cytokines were significantly upregulated in both BALF and serum (all P<0.01), and the activity of MPO in BALF was also remarkedly increased (P<0.01). The total protein concentration of BALF was significantly elevated (P<0.01). The pathological observation of lung tissue showed a large number of inflammatory cells infiltration accompanying pulmonary hemorrhage, alveolar collapse, hyaline membrane formation and alveolar septal thickening, and the lung injury scores significantly increased (P<0.01). Conclusions Intratracheal aerosolization of a single dose of 0.02 mg PQ can successfully induce ALI in mice. Key words: Paraquat; Acute lung injury; Animal model; Intratracheal aerosolization