Fig. 4

Histopathological changes after multiple challenges of PM-b. A Experimental schedule. PM-b or PBS were intratracheally injected on days 0, 3, and 7. Mice were euthanized on day 10 (PBS injected mice: n = 5; PM-b injected mice: n = 10) or day 28 (PBS injected mice: n = 5; PM-b injected mice: n = 8). B, C Representative images of the lung of mice on days 10 (B) and 28 (C). Pulmonary histopathological changes were evaluated by three different types of stainings (HE: Hematoxylin-Eosin staining; MT: Masson’s Trichrome staining; SR: Sirius Red staining). Scale bar: 100 μm