TBMS1 ameliorates PM2.5-induced histological changes in the lung. Inflammatory cell infiltration, interstitial edema, alveolar space diminishment and hyperemia were observed in the control group. However, these alterations were markedly attenuated by TBMS1 administration. The white, blue, red and yellow arrows indicate sites of inflammatory cell infiltration, interstitial edema, alveolar space diminishment and hyperemia, respectively. (A) Control group. (B) PM2.5 group. (C) PM2.5 + TBMS1 45 mg/kg group. (D) PM2.5 + TBMS1 90 mg/kg group. (E) PM2.5 + TBMS1 180 mg/kg group. Magnification, ×200. TBMS1, Tubeimoside I; PM2.5, particulate matter <2.5 µm in diameter.