Exercise as a new physiological stimulus for brown adipose tissue activity.
OBJECTIVE
Brown adipose tissue (BAT) plays a major role in body energy expenditure counteracting obesity and obesity-associated morbidities. BAT activity is sustained by the sympathetic nervous system (SNS). Since a massive activation of the SNS was described during physical activity, we investigated the effect of endurance running training on BAT of young rats to clarify the role of exercise training on the activity and recruitment state of brown cells.


RESULTS
Male, 10-week-old Sprague Dawley rats were trained on a motor treadmill (approximately 60% of VO2max), 5 days/week, both for 1 and 6 weeks. The effect of endurance training was valuated using morphological and molecular approaches. Running training affected on the morphology, sympathetic tone and vascularization of BAT, independently of the duration of the stimulus. Functionally, the weak increase in the thermogenesis (no difference in UCP-1), the increased expression of PGC-1α and the membrane localization of MCT-1 suggest a new function of BAT. Visceral fat increased the expression of the FOXC2, 48 h after last training session and some clusters of UCP-1 paucilocular and multilocular adipocytes appeared.


CONCLUSIONS
Exercise seemed a weakly effective stimulus for BAT thermogenesis, but surprisingly, without the supposed metabolically hypoactive effects. The observed browning of the visceral fat, by a supposed white-to-brown transdifferentiation phenomena suggested that exercise could be a new physiological stimulus to counteract obesity by an adrenergic-regulated brown recruitment of adipocytes.
Department of Biomolecular Sciences, Università di Urbino Carlo Bo, Urbino, Italy. rita.dematteis@uniurb.it
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R
De Matteis
F
F
Lucertini
M
M
Guescini
E
E
Polidori
S
S
Zeppa
V
V
Stocchi
S
S
Cinti
R
R
Cuppini
D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D054338:Cell Transdifferentiation; D004734:Energy Metabolism / Q000502:physiology*; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D050152:Intra-Abdominal Fat / Q000378:metabolism; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D027501:Monocarboxylic Acid Transporters / Q000235:genetics / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D009765:Obesity / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012420:Running / Q000502:physiology; D013564:Sympathetic Nervous System / Q000378:metabolism; D027981:Symporters / Q000235:genetics / Q000378:metabolism; D022722:Thermogenesis; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000071256:Uncoupling Protein 1; D000099233:Monocarboxylate Transport Protein 1
D051858:Forkhead Transcription Factors; D007473:Ion Channels; D019344:Lactic Acid; D024101:Mitochondrial Proteins; D027501:Monocarboxylic Acid Transporters; D009638:Norepinephrine; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D027981:Symporters; D014157:Transcription Factors; D000071256:Uncoupling Protein 1; D000099233:Monocarboxylate Transport Protein 1; C501429:Ppargc1a protein, rat; C000604373:Ucp1 protein, rat; C082078:mesenchyme fork head 1 protein