Fig. 2

Therapeutic effect of IMRC-EVs on BLM-induced lung fibrosis mouse model. a Schematic diagram of the in vivo experimental design of the BLM-induced PF mouse model. b Changes in relative body weight (%) of mice receiving different interventions. c Lung coefficient (wet lung weight/total body weight) of all treatment groups. d–f Mouse lung tissues from each group were collected and embedded in paraffin for histological analysis. d Representative histology of lung sections stained with H&E. The small graphs inside the figure represent whole lung from all groups at day 21 post-injury. e Representative Masson staining. myofibers (red), collagen fibers (blue), and nucleus (black-purple). f Representative picrosirius red staining. Scale bar = 100 μm. Collagen I displays an orange-red birefringence under polarized light, whereas Collagen III has a green birefringence. g, h Immunohistochemical (IHC) analysis of Collagen I (col-I) (g), and α-smooth muscle actin (α-SMA) (h) after IMRC-EVs and MRC5-EVs transplantation. Original magnification is ×200, scale = 100 μm. i Quantification of fibrosis by Ashcroft score. Ashcroft score was measured by averaging the score from a blinded and a non-blinded scorer. j Changes in hydroxyproline levels of the lung in different treatment groups. k, l The quantification of relative immunostaining of Col-I (k) and α-SMA (l). Data are represented as the mean ± SD; *P < 0.05, **P < 0.01, ***P < 0.001