Fig. 2

MSCs-exo ameliorated the histopathologic damage of cGVHD mice. a H&E-stained skin lesions of cGVHD mice treated with PBS or Fib-exo showed typical dermal fibrosis with a lack of subcutaneous fat and hair follicles, as well as epidermal hyperplasia with increased thickness. By contrast, MSCs-exo-treated mice exhibited reduced levels of dermal fibrosis and hyperplasia. b Masson-stained skin section showing obvious fibrosis with collagen deposition in cGVHD mice treated with PBS or Fib-exo, whereas little Masson-positive staining was present in cGVHD mice treated with MSCs-exo. The statistics of Masson-positive fibrosis area percentage also showed least fibrosis in the skin from MSCs-exo-treated cGVHD mice. The fibrosis percentage was determined as the percentage of blue collagen-stained area relative to the total tissue in one upper field. c Representative H&E staining images displaying inflammation with an obvious leukocytic infiltration and irregular structure of the lung. However, lung tissue of MSCs-exo-treated mice appeared to be normal with a network of air sacs. d Distinct Masson-stained fibrosis and narrow small airways were identified in the lung tissue of control cGVHD mice. By contrast, MSCs-exo-treated mice presented a lack of Masson staining. e Representative liver H&E images indicating inflammatory cell recruitment around the hepatic duct in cGVHD mice, and MSCs-exo treatment reduced the infiltration of inflammatory cells. f The representative image and statistics showed that fibrosis in the liver was alleviated by MSCs-exo application with reduced Masson staining. Data are expressed as the mean ± SEM. *P < .05 and **P < .01; ns not significant