Fig. 1

Expression of HSP25 protein during PF development. A Experimental scheme of focal exposure to high-dose radiation (75 Gy) to mice by period. B Representative images of mouse lung sections stained with Masson’s trichrome (top) at indicated times after focal 75 Gy irradiation (IR). Representative immunohistochemistry images of HSP25 and pHSP25 (S86) in mouse lung tissues (middle and bottom). Graphs show scores quantifying collagen deposition, and each protein -positive cells. Magnification, 200 × . Scale bar, 100 μm. C Pro-SPC (green) was used to identify type II AECs co-stained with HSP25 (red) and α-SMA (violet). Expression levels of HSP25 and α-SMA were upregulated in type II AECs of the irradiated lung tissue. Magnification, 400 × . Scale bar, 20 μm. Quantification of stained tissues was performed (n ≥ 3, mean ± SD). D Lung tissues were stained with anti-p65 antibody to investigate subcellular localization. Quantification of nuclear p65 level co-localized with DAPI was performed. Magnification, 400 × . Scale bar, 20 μm. (n ≥ 3, mean ± SD). E Representative immunohistochemical staining of Twist, IL-1β, and IL-6. Magnification, 200 × . Scale bar, 100 μm. Quantification of stained tissues was performed (n ≥ 3, mean ± SD). F Summary graph of RIPF in the mouse model used in this study. Inflammation represented by NFkB activation appeared initially, followed by EMT. Progression of fibrosis represented by α-SMA and expression of HSP27 continued to increase until the end of the experiment. The pattern remained the same