Fig. 2

IFN-α enhanced foam cell formation. THP-1-derived macrophages (TDMs), Raw 264.7 cells, and mouse bone marrow-derived macrophages (BMDMs) were stimulated with oxLDL in the presence or absence of IFN-α, and foam cell formation was measured by oil red O staining (a, left). The cells were examined by light microscopy and the percentages of oil red O positive cells in 5 microscopic fields for each independent experiment were counted and calculated (a, right). One dot stands for an independent experiment. The extent of Dil-oxLDL uptake by BMDMs was determined and statistically analyzed and the results are shown (b, n = 6). Similar to the finding shown in b, the extent of Dil-oxLDL uptake by TDMs was determined (c, n = 4). Foam cell formation induced by different stimuli, including LDL and cholesterol crystals (CCs), was measured (d). Asterisks indicate values that are significantly different from the relevant control (*P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001). n, sample numbers of independent experiments