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Figure 4 | Particle and Fibre Toxicology

Figure 4

From: Iron oxide nanoparticles suppress the production of IL-1beta via the secretory lysosomal pathway in murine microglial cells

Figure 4

IONPs attenuated the cathepsin B enzyme activity of secretory lysosomes in LPS-stimulated microglia. Primary microglial cells (4 × 105 cells/mL) were either left untreated (naïve; NA), or pretreated with IONPs (1–50 μg Fe/mL) for 30 min followed by stimulation with LPS (100 ng/mL) for 24 h. (A) The cells pretreated with IONPs and stimulated with LPS were incubated with the cathepsin B substrate (red) for 1 h at 37°C and then stained for the secretory lysosome marker Rab27a (green). The fluorescence was visualized by confocal microscopy. Note the presence of orange signals in the merged images indicating the colocalization of cathepsin B and Rab27a. (B) The red fluorescence of 5000 single cells was measured by flow cytometry. Data are expressed as the mean ± SE of triplicate cultures. Results are a representative of three independent experiments. * p < 0.05 compared to the control group. MFI, mean fluorescence intensity.

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