Figure 2. Mouse scBAT continues to grow after birth.
(A) Diagram showing the anatomical location of scBAT in adult mice (ventral view). (B) Representative images showing the anatomical location of scBAT in 8-, 24-, and 52-week-old mice. Top row: Lower-magnification images of the ventral neck. sg, salivary gland; tr, trachea; jv, external jugular vein. scBAT is outlined by the black dotted line. Bottom row: Higher-magnification images of the ventral neck showing close-up images of scBAT. *scBAT. Scale bars: 1,000 μm. (C) Representative image of the ventral neck from an 8-week-old mouse showing the sternocleidomastoid muscle (#) after scBAT was removed. Scale bars: 1,000 μm. (D) Representative images of iBAT and scBAT isolated from an 8-week-old mouse. Arrows point to the part of the scBAT that is located behind the external jugular vein. Scale bars: 1,000 μm. (E) Body weight, iBAT and scBAT mass, and weight/mass ratio of iBAT and scBAT in 3-, 8-, 26-, and 52-week-old male mice. n = 5–6. (F) Representative H&E-stained sections of iBAT, scBAT, iWAT (inguinal WAT), and eWAT (epididymal WAT) isolated from 8-week-old male mouse. n = 3. Scale bars: 50 μm. (G) Lipid droplet size distribution in iBAT, scBAT, iWAT, and eWAT from 8-week-old male mice. Percentages for different lipid droplet sizes were measured in 4–8 randomly selected H&E-stained sections from 3 mice. (H) Relative mRNA expression of BAT selective markers in iBAT, scBAT, iWAT, and eWAT isolated from 8-week-old male mice. Data are presented as mean ± SEM. n = 4–5. ****P < 0.0001, ***P < 0.001, **P < 0.01, *P < 0.05. One-way ANOVA.