Fig. 3.

Transmission electron microscopy reveals many similarities between PVAT and BAT. Sections of brown (A and B) and perivascular adipose (C and D) were taken and stained with osmium tetroxide. In ND conditions, brown (A) and perivascular adipose (C) appear very similar with mulitilocular lipid droplets and abundant mitochondria. Two prominent changes were noted in high-fat feeding conditions; lipid droplets in BAT, but not PVAT, lose their avidity for osmium textroxide (B), and mitochondria become swollen with unfolded cristae (D); the latter effect was more prominent in perivascular adipose but also observed in brown adipose after a longer duration of HFD. LD, lipid droplet; M, mitochondria; EC, endothelial cell; RBC, red blood cell. Magnification: ×7900; scale bar = 2 μm.