Effects of exercise training on adipogenesis of stromal-vascular fraction cells in rat epididymal white adipose tissue.
OBJECTIVE
Previous studies have shown that exercise training reduced white adipose tissue (WAT) mass compared to that in sedentary controls, and that the smaller mass contained fewer adipocytes. However, the effect of exercise training on adipogenesis is not completely clear. Therefore, we re-examined the effect of exercise training on adipocyte numbers in WAT and, if such an effect was found tested the adipogenic responses of stromal-vascular fraction (SVF) cells containing adipose tissue-derived stem cells (ADSC) in epididymal WAT from exercise-trained (TR) rats.


METHODS
Wistar male rats were divided into two groups: control (C) and TR. The TR rats were subjected to exercise on a treadmill for 9 weeks. SVF cells containing ADSC were separated from epididymal WAT by centrifugation. Expression of adipocyte differentiation-related genes and adipogenesis of SVF cells were examined.


RESULTS
In SVF cells of TR rats, the expression of peroxisome proliferator-activated receptor γ (PPARγ) and that of PPARγ target lipogenic genes was dramatically downregulated, whereas that of preadipocyte factor-1 gene was significantly upregulated. Lipid accumulation in SVF cells of TR rats after the induction of adipocyte differentiation was significantly suppressed in comparison with that of C rats. Moreover, increased expression of hypoxia-inducible factor-1α (HIF-1α) protein was observed in SVF cells of TR rats. Pre-treatment of YC-1, a potent HIF-1α inhibitor, in SVF cells of TR rats restored adipogenesis.


CONCLUSIONS
These results suggest that exercise training suppresses the ability of SVF cells to differentiate into adipocytes, and that underlying mechanisms involve the upregulation of HIF-1α expression.
Sakurai
T
T
Department of Molecular Predictive Medicine and Sport Science, Kyorin University, Tokyo, Japan. sakutaku@ks.kyorin-u.ac.jp
Endo
S
S
Hatano
D
D
Ogasawara
J
J
Kizaki
T
T
Oh-ishi
S
S
Izawa
T
T
Ishida
H
H
Ohno
H
H
D050156:Adipogenesis / Q000502:physiology*; D052436:Adipose Tissue, White / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D000818:Animals; D015992:Body Mass Index; D002454:Cell Differentiation / Q000502:physiology; D004435:Eating; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D008297:Male; D010805:Physical Conditioning, Animal; D011401:Promoter Regions, Genetic; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D017154:Stromal Cells / Q000502:physiology*
C497444:Hif1a protein, rat; D051795:Hypoxia-Inducible Factor 1, alpha Subunit