Figure 2
IONPs differentially affected the production of IL-1β and TNF-α, and the activity of ICE and TACE 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 and B) The level of IL-1β and TNF-α in the supernatants was measured by ELISA. (C and D) The cell lysates were incubated with fluorogenic ICE or TACE substrates for 1 h at 37°C. The fluorescence of cleaved substrates was detected using a fluorescent microplate reader. Data are expressed as the mean ± SE of triplicate cultures. N.D., the level of IL-1β and TNF-α was below the limit of detection. * p < 0.05 compared to the LPS group. Results are a representative of three independent experiments. MFI, mean fluorescence intensity.