Figure 3.

Representative samples of pathological changes in Sham group (a), (d), RT group (b), (e), and RT + DXM group (c), (f). Dexamethasone attenuates radiation-induced pneumonitis and pulmonary fibrosis. Mice were administered dexamethasone (0.42 mg/kg/day) intraperitoneally on days 1 to 30 after irradiation. Mice were sacrificed on specific time point, and lung tissue was fixed and excised into tissue sections for the detection of pulmonary inflammation and collagen deposition by H&E or Masson staining. In (a), (b), and (c), dexamethasone promoted the resolution of the radiation-induced pulmonary inflammation in the 4th week as indicated by H&E staining of the lung sections. (a) Sham group. (b) RT group, significant radiation pneumonitis and inflammatory cell infiltration (black arrows position). (c) RT + DXM group, inflammatory cell infiltration was significantly reduced without significant leakage. In (d), (e), and (f), dexamethasone promoted the resolution of the radiation-induced pulmonary fibrosis in the 16th week as indicated by Masson staining of the lung sections. (d) Sham group. (e) RT group, fibrosis stage, a large number of collagen depositions (black arrow position). (f) RT + DXM group, collagen deposition was significantly reduced compared with RT group; the alveolar structure is relatively intact.