Fig. 1

Adipocyte-specific Mipep knockout (aMKO) in mice is associated with reduced fat mass, disturbed mitochondrial morphology in WAT, and a whitening of BAT. (A) Computed tomography axial images of gWAT and sWAT from 19–20-week-old control and aMKO mice (left, representative image: right, quantitative value of the area). (B) Images of gWAT and sWAT from 27-week-old control and aMKO mice. (C) Hematoxylin and eosin staining of gWAT from 22-week-old control and aMKO mice. Arrows indicate lipoblast features. Scale bar: 50 μm. (D) Adipocyte size distribution in gWAT from control and aMKO mice. Adipocyte size was classified into 1000 μm² bins and the percentage of total adipocytes in each bin per sample was plotted. At least 100 adipocytes were measured for each sample. (E) Electron micrographs of mitochondria in adipocytes from gWAT from control (α) and aMKO (β, γ and δ) mice. While mitochondria with many cristae were observed in the cytosol of adipocytes in control adipocytes (α) and non-adipocyte cells from aMKO mice (γ), mitochondria in aMKO adipocytes were more circular and larger with fewer cristae (β and δ). Scale Bar: 3 μm. (F) Images of BAT from 31-week-old control and aMKO mice. (G) Hematoxylin and eosin staining of BAT from 27-week-old control and aMKO mice. Scale bar: 50 μm. (H) Electron micrographs of mitochondria in the adipocytes of BAT from control and aMKO mice. Scale Bar: 3 μm. Each dot represents one mouse. Values are mean ± SD. Differences between values were analyzed by Student’s t-test. *p < 0.05 and **p < 0.01 vs. control. BAT, brown adipose tissue; gWAT, gonadal white adipose tissue; sWAT, subcutaneous white adipose tissue.