Effect of exercise training and carvedilol treatment on cardiac function and structure in mice with sympathetic hyperactivity-induced heart failure
Rev. bras. pesqui. méd. biol
; Braz. j. med. biol. res;41(9): 812-817, Sept. 2008. ilus
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| ID: lil-492882
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ABSTRACT
The present investigation was undertaken to study the effect of â-blockers and exercise training on cardiac structure and function, respectively, as well as overall functional capacity in a genetic model of sympathetic hyperactivity-induced heart failure in mice (alpha2A/alpha2CArKO). alpha2A/alpha2CArKO and their wild-type controls were studied for 2 months, from 3 to 5 months of age. Mice were randomly assigned to control (N = 45), carvedilol-treated (N = 29) or exercise-trained (N = 33) groups. Eight weeks of carvedilol treatment (38 mg/kg per day by gavage) or exercise training (swimming sessions of 60 min, 5 days/week) were performed. Exercise capacity was estimated using a graded treadmill protocol and HR was measured by tail cuff. Fractional shortening was evaluated by echocardiography. Cardiac structure and gastrocnemius capillary density were evaluated by light microscopy. At 3 months of age, no significant difference in fractional shortening or exercise capacity was observed between wild-type and alpha2A/alpha2CArKO mice. At 5 months of age, all alpha2A/alpha2CArKO mice displayed exercise intolerance and baseline tachycardia associated with reduced fractional shortening and gastrocnemius capillary rarefaction. In addition, alpha2A/ alpha2CArKO mice presented cardiac myocyte hypertrophy and ventricular fibrosis. Exercise training and carvedilol similarly improved fractional shortening in alpha2A/alpha2CArKO mice. The effect of exercise training was mainly associated with improved exercise tolerance and increased gastrocnemius capillary density while beta-blocker therapy reduced cardiac myocyte dimension and ventricular collagen to wild-type control levels. Taken together, these data provide direct evidence for the respective beneficial effects of exercise training and carvedilol in alpha2A/alpha2CArKO mice preventing cardiac dysfunction. The different mechanisms associated with beneficial effects of exercise...
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Propanolaminas
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Carbazóis
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Antagonistas Adrenérgicos beta
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Insuficiência Cardíaca
Tipo de estudo:
Guideline
Limite:
Animals
Idioma:
En
Revista:
Braz. j. med. biol. res
/
Rev. bras. pesqui. méd. biol
Assunto da revista:
BIOLOGIA
/
MEDICINA
Ano de publicação:
2008
Tipo de documento:
Article
/
Project document
País de afiliação:
Brasil
País de publicação:
Brasil