Figure 2.

Inhibition of FactorXa prevents whitening and dysfunction of brown adipose tissue

Mice were fed a high-fat diet (HFD) from 4 weeks of age with or without the administration of an FXa inhibitor (FXa-i). Physiological studies were performed at age 13 to 19 weeks for FXa-i treatment, and samples were collected at age 18 to 22 weeks.

(A) Enzyme-linked immunosorbent assay study of Factor Xa in brown adipose tissue (BAT) from mice aged 19-22 weeks fed a high-fat diet (HFD; Con HFD) or HFD + FXa inhibitor (FXa-i HFD; n = 8, 8).

(B) Hematoxylin and eosin (HE) staining of BAT from the indicated mice. Scale bar = 100 μm. Right panel indicates the quantification of large lipid droplets in the indicated mice (n = 6, 9). Large lipid droplets were defined as droplets with a surface area >1000 μm².

(C) Staining with dihydroethidium (DHE) in brown adipose tissue (BAT) from mice fed the HFD (Con HFD) or HFD + FXa-i (FXa-i HFD). Scale bar = 50 μm. Right panels indicate quantification shown as relative dihydroethidium (DHE) level (DHE area of FXa-i HFD/Con HFD, n = 9, 6).

(D) Findings on transmission electron microscopy in the indicated mice (scale bar = 2 μm). Right panels indicate mitochondrial area (%; analyzed as mitochondrial area/[non-capillary and non-lipid area]) in the pericapillary area of respective groups (n = 4, 4).

(E and F) Cold tolerance test (CTT; E, n = 7, 7) or glucose tolerance test (GTT; F, n = 14, 17) in the indicated mice aged 13 weeks for CTT, and 12 weeks for GTT.

(G) Oxygen consumption (VO₂), CO₂ production (VCO₂), energy expenditure (EE), and respiratory exchange ratio (RER) in the indicated groups aged 14-16 weeks (n = 12, 12, 12, 12). Data were analyzed by a 2-tailed Student’s t test (A, B, C, D, G) or 2-way repeated measures ANOVA (E, F). ∗p < 0.05, ∗∗p < 0.01. Values represent the mean ± SEM NS = not significant. All data are from different biological replicates. See also Figure S2.