Fig. 5

M2 macrophage-secreted exosomes promote pulmonary interstitial fibroblast proliferation. a Arg-1 activity of M0 and M2 macrophages, *p < 0.05 vs. M0 macrophages. b Positive expression rates of CD9, CD63 and CD81 in M0 and M2 macrophages, * p < 0.05 vs. M0 macrophages. c Exosome morphology observed by TEM. D, Exosome particle size analysis. e The protein levels of the exosomal markers CD9, CD63 and CD81 examined by western blot analysis. f The internalization of M2 macrophage-secreted exosomes by pulmonary interstitial fibroblasts at different time points; green indicates PKH67-labeled exosomes, and red represents pulmonary interstitial fibroblasts, bar = 25 μm. g, Edu labeling to examine the proliferation of pulmonary interstitial fibroblasts after a coculture with exosomes (200 × ). H, Quantification of the results in G. * p < 0.05 vs. pulmonary interstitial fibroblasts. I, Expression of Collagen 1 A, Collagen 3 A and α-SMA in pulmonary interstitial fibroblasts after a coculture with exosomes, as measured by RT-qPCR. * p < 0.05 vs. pulmonary interstitial fibroblasts. Arg-1, arginase 1; EdU, 5-ethynyl-2’-deoxyuridine; α-SMA, α-smooth muscle actin; and RT-qPCR, reverse transcription quantitative polymerase chain reaction. The results were measurement data and were analyzed using an unpaired t test. The results are expressed as the mean ± standard deviation. The experiment was conducted in triplicate