Fig. 2
The secretion of exosomes by macrophages is increased by silica exposure. (A-B). The morphology of exosomes derived from the supernatant of RAW264.7 macrophages and THP-1 macrophages treated with silica dust was observed by TEM. The yellow arrowheads indicate exosomes. The scale bar represents 100 nm. (C). Representative western blot image showing the expression of HSP70, TSG101 and CD63 in exosomes derived from RAW264.7 macrophages and THP-1 macrophages with or without SiO2 exposure; equal volumes of exosomes (in a total volume of 30 µl) were subjected to SDS–PAGE. (D). NTA showing the size distribution of exosomes derived from RAW264.7 macrophages and THP-1 macrophages treated with SiO2. (E). Micro-BCA assay analysis of the total protein content of exosomes derived from RAW264.7 macrophages and THP-1 macrophages treated with or without SiO2 for 36 h. n = 3 per group. The data are representative of three individual experiments and were analysed by two-way ANOVA. *P < 0.05, **P < 0.01. Abbreviations SiO2 = silica dust; NC-Exo = exosomes derived from cells without SiO2 exposure; SiO2-Exo = exosomes derived from SiO2-exposed macrophages; TEM = transmission electron microscopy; NTA = nanoparticle tracking analysis; BCA = bicinchoninic acid