Impact of Exercise and Detraining during Childhood on Brown Adipose Tissue Whitening in Obesity

Figures

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  Figure 1. Metabolic characteristics. (A) changes in body weight; (B) daily food intake (per three rats in a cage); (C) daily running time; (D) daily running distance. LETO, Long-Evans Tokushima Otsuka rat; OLETF, Otsuka Long-Evans Tokushima Fatty rat. LETO Sed, LETO non-exercise sedentary; OLETF Sed, OLETF non-exercise sedentary; OLETF Ex, OLETF non-exercise from 4- to 10-weeks-old and exercise from 10- to 12-weeks-old; OLETF DT, OLETF exercise from 4- to 6-weeks-old and non-exercise detraining from 6- to 12-weeks-old; OLETF Ex4–12w, OLETF exercise from 4- to 12-weeks-old. Values represent means ± standard deviation. *, †, ‡, and § show significantly different between the OLETF Sed vs. LETO Sed groups, the OLETF Ex vs. OLETF Sed groups, the OLETF DT vs. OLETF Sed groups, and the OLETF Ex4–12w vs. OLETF Sed groups, respectively, p < 0.05.

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  Figure 2. Histological influences of exercise on the skeletal muscle. (A) wet weight of the skeletal muscle; (B) the ratio of muscle wet weight to body weight; (C) expression level of ubiquitinated proteins; (D) phosphorylation of p70S6K; (E) representative sections of skeletal muscle stained with adenosine triphosphatase (ATPase) (pH 4.6); (F) cross-sectional area of type I, IIA, IID, and type IIB fibers. I: Type I fiber; IIA: Type IIA fiber; IID: Type IID fiber; IIB: Type IIB fiber. Values represent means ± standard deviation. For the expression level of protein (C,D) values are calculated as the fold changes relative to the LETO Sed group. *, †, and ‡ show significantly different from the LETO Sed, OLETF Sed, and OLETF Ex groups, respectively, p < 0.05.

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  Figure 3. Chronic influences of exercise on brown adipose tissue at 12-weeks-old. (A) Wet weight of the brown adipose tissue; (B) Ratio of brown adipose tissue wet weight to body weight; (C) Representative section of brown adipose tissue stained with hematoxylin and eosin in the OLETF Sed group; (D) Representative sections in the peripheral area of the adipose lobule; (E) Diameter of whitened unilocular adipocyte in the central area of the lobule; (F) Density of whitened unilocular adipocyte in the central area of the lobule; (G) Diameter of hypertrophic unilocular adipocyte in the peripheral area of the lobule; (H) Density of hypertrophic unilocular adipocyte in the peripheral area of the lobule; (I) Expression levels of the proteins in the brown adipose tissue at 12-weeks-old; (J) Representative images for the proteins. OLETF DT, OLETF exercise from 4- to 6-weeks-old and non-exercise detraining from 6- to 12-weeks-old. Arrowheads indicate whitened unilocular adipocytes located in the central area of the adipose lobule. Arrows indicate hypertrophic unilocular adipocytes located in the peripheral area of the adipose lobule. Values represent means ± standard deviation. *, †, and ‡ show…

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  Figure 4. Experimental design. LETO Sed, LETO non-exercise sedentary; OLETF Sed, OLETF non-exercise sedentary; OLETF Ex, OLETF non-exercise from 4- to 10-weeks-old and exercise from 10- to 12-weeks-old; OLETF DT, OLETF exercise from 4- to 6-weeks-old and detraining from 6- to 12-weeks-old. Dark circles indicate the point of tissue sampling. Solid and dotted lines indicate exercise and non-exercise periods, respectively. Tissue samples were collected at 6- (n = 3 in the LETO Sed, OLETF Sed, and OLETF DT groups) or 12 (n = 6 in each group)-weeks-old. Tissue samples at 6-weeks-old were used to confirm the development process of BAT whitening (data not shown).