Figure 6.

Brown adipose tissue (BAT) macrophage infiltration and lipid droplet accumulation is perivascular. (a–h) ×10 and ×40 hematoxylin and eosin (H&E) stain of BAT from (a,e) low-fat diet (LFD), (b,f) high-fat diet (HFD), (c,g) standard chow (SC), and (d,h) cafeteria diet (CAF). The box indicates area of the ×10 image magnified to ×40 imaging when appropriate for H&E stained tissues. Lipid droplet accumulation was notable in cells along the length of vessels in LFD, HFD, and especially CAF-fed tissues. (i–l) F4/80 was used to identify macrophages which can be seen as cells staining dark brown (marked with #) in (j) HFD and (l) CAF (×40). It is important to note that F4/80 positive macrophages colocalized to the perivascular regions where high lipid accumulation was noted and that CAF F4/80 positive cells stained stronger and were more numerous than those in HFD animals. Representative images are shown. (n = 4, SC, LFD, and HFD, n = 5 CAF). See Supplementary Table S4 online for detailed description.