Fig. 1

The number of exosomes secreted by alveolar macrophages is significantly increased in the BALF of mice with silicosis. (A). Representative image of CD68 expression in the lung tissue of mice treated with saline or silica dust and examined by immunohistochemical staining (scale bar = 50 μm). (B-D). After 28 days of exposure to silica dust, BALF was collected, the morphology of the cells in BALF was observed by Giemsa staining (scale bar = 20 μm), and CD68 expression in these cells was examined by western blot analysis (B). The number of AMs in the BALF (C) and the expression of IL-1β, IL-6 and TNF-α in AMs were examined by RT–PCR (D). n = 5 mice per group. Saline = saline-treated mice; silica = silica dust-treated mice. (E-H). Exosomes were isolated from the BALF of mice treated with saline or silica dust, the expression of exosome-related markers (HSP70, TSG101 and CD63) was examined by western blot analysis (E), exosome morphology was observed by TEM (scale bar = 100 nm) (F), the size distribution of the exosomes was analysed by NTA (G), and the total exosomal protein concentration was examined by a micro-BCA assay (H). n = 15 mice per group. (I). Representative image showing the expression of CD68, CD31, PDPN, SP-B, caveolin-1 and HSP70 in exosomes derived from BALF and measured by western blot analysis. n = 15 mice per group. The data are representative of three individual experiments and expressed as the mean ± SEM. The data were analysed by two-tailed Student’s t test or two-way ANOVA. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, ns = not significant. Abbreviations SiO₂ = silica dust; BALF = bronchoalveolar lavage fluid; AMs = alveolar macrophages; TEM = transmission electron microscope; NTA = nanoparticle tracking analysis