Top, Panel A illustrates aortic regions with intact periaortic adipose tissue (thoracic and abdominal) dissected for analyses from lean (ob/+) and obese (ob/ob) mice. Thoracic (B,C) and abdominal (D,E) aortic sections (5 m) from ob/+ (B,D) and ob/ob (C,E) mice were stained with hematoxylin and eosin (H&E). Adipose tissue surrounding thoracic aortas was composed of multilocular brown adipocytes (B: 40X; insets: 10X). In contrast, adipocytes surrounding abdominal aortas were primarily unilocular (C: 40X; insets: 10X). With obesity (C,F), both brown and white adipocytes surrounding aortas were hypertrophied.