Figure 1.

Inhibition of PI3K increased alveolar epithelial cells apoptosis in a COPD mouse model induced by PM2.5. Hematoxylin and eosin staining of lung tissue samples (a), lung wet weight/dry weight rate (b), and caspase-3/9 activity (c and d). **P < 0.01 compared with sham group; ^##P < 0.01 compared with COPD model group. PI3K, phosphatidylinositol 3-kinase; COPD, chronic obstructive pulmonary disease; PM2.5, particulate matter with a diameter <2.5 µm; Sham, sham control mice group; Model, mouse model with COPD induced by PM2.5; PI3K inhibitor, treatment with PI3K inhibitor group.