Fig. 7.

Macrophages in all regions of mLNs incorporate lipid droplets, (A) Macrophages (M, CD11b⁺) are present in all sinuses and the medullary region of mLNs. (B-E) mLNs were isolated 10 weeks after LFD (B) or HFD (C-E) feeding, fixed and stained with uranyl acetate and lead citrate. Representative pictures (1.8 kx) of the intermediary sinus are shown. (C) In all regions, macrophages carried increased numbers of lipid droplets of larger sizes after HFD feeding. (D) Lipophages (8.9 kx) showing heterolysosomes (HL) were detected in mLNs, independent of the diet, whereas foam cells (7.8 kx) were found in mLNs only after HFD feeding (E). Abbreviations: FC, foam cell; FDC, follicular dendritic cell; FRC, fibroblastic reticulum cell; HEV, high endothelial venule; HL, heterolysosome; LD, lipid droplet; LEC, lymphatic endothelium cell; LP, lipophage; M, macrophage; MRC, marginal reticulum cell; and SRC, sinusoidal reticulum cell.