Figure 9. Human MSCs and their exosomes ameliorate experimental silicosis.
(a) Photomicrographs of lung sections stained with haematoxylin and eosine from mice 28 days after intratracheal administration of silica (0.2 g kg−1) alone or followed 3 days later with an intravenous injection of human MSCs, human MSC-derived exosomes (∼3 × 1011 exosomes containing 40 μg protein) or human fibroblasts (scale bars, 500 μ). (b) Upper panel, photomicrographs of Diff-Quick-stained cytospins of BAL from mice in a. Lower panel, differential cell counts showing counts of total cells (left) and percentage of macrophages, lymphocytes, neutrophils and eosinophils (right panels). *P<0.05 compared with control, †P<0.05 compared with fibroblasts treated mice by Student’s t-test. (c) Hydroxyproline content of lung tissue from animals treated as in a. *P<0.001 compared with saline by Student’s t-test. †P<0.05 compared with silica, human MSC or fibroblast by ANOVA. (d) Quantification of mouse TNF, IL-6, IL-10 and Col1α1 levels in lung tissue from mice in a at 14 and 28 d post treatment. Plotted values (mean±s.e.m.) are representative of experiments using 15 animals per group and repeated three times. *P<0.001 compared with saline by Student’s t-test, †P<0.05 compared with silica by ANOVA.