Figure 7: Alpinia officinarum ameliorated particulate matter-induced histological changes in the lung. AO: Alpinia officinarum; PM: particulate matter; LD: low dose; MD: medium dose; HD: high dose. Lung sections were obtained from vehicle-treated mice (A), PM treated mice (B), PM+LD-AO treated mice (C), PM+MD-AO treated mice (D) and PM+HD-AO treated mice (E). After Masson staining, histological examination was performed by light microscopy (magnification × 200). 1 indicates normal lung tissue, 2 indicates inflammatory cell infiltration, 3 indicates edema and 4 indicates pulmonary fibrosis.