Figure 6.

High-density lipoprotein (HDL) promotes a formation of THP-1 macrophage-derived foam cells during M. avium infection. THP-1 macrophages were infected by M. avium with (+) or without (−) HDL. (a) Representative light microscopic images of the cells stained with Oil red O (ORO) and hematoxylin are shown. The scale bar is 25 nm. (b) The numbers of lipid droplets (LDs) per cell were calculated by counting of those number for 50 cells. (c) The amount of LDs was also quantitatively analyzed by measuring absorbance (at 540 nm) of ORO extracted from the cells. The values were indicated by mean ± SEM (n = 3, ^∗ P < 0.05, ^∗∗ P < 0.01). NS: not significant.