title: Exercise training starting at weaning age preserves cardiac pacemaker function in adulthood of diet-induced obese rats.
abstract: Peripheral sympathetic overdrive in young obese subjects contributes to further aggravation of insulin resistance, diabetes, and hypertension, thus inducing worsening clinical conditions in adulthood. Exercise training has been considered a strategy to repair obesity autonomic dysfunction, thereby reducing the cardiometabolic risk. Therefore, the aim of this study was to assess the effect of early exercise training, starting immediately after weaning, on cardiac autonomic control in diet-induced obese rats. Male Wistar rats (weaning) were divided into four groups: (i) a control group (n = 6); (ii) an exercise-trained control group (n = 6); (iii) a diet-induced obesity group (n = 6); and (iv) an exercise-trained diet-induced obesity group (n = 6). The development of obesity was induced by 9 weeks of palatable diet intake, and the training program was implemented in a motor-driven treadmill (5 times per week) during the same period. After this period, animals were submitted to vein and artery catheter implantation to assess cardiac autonomic balance by methylatropine (3 mg/kg) and propranolol (4 mg/kg) administration. Exercise training increased running performance in both groups (p < 0.05). Exercise training also prevented the increased resting heart rate in obese rats, which seemed to be related to cardiac pacemaker activity preservation (p < 0.05). Additionally, the training program preserved the pressure and bradycardia responses to autonomic blockade in obese rats (p < 0.05). An exercise program beginning at weaning age prevents cardiovascular dysfunction in obese rats, indicating that exercise training may be used as a nonpharmacological therapeutic strategy for the treatment of cardiometabolic diseases.
authors.affiliation: a Department of Physiology and Biophysics, Institute of Biological Sciences; Federal University of Minas Gerais, 31270-901 Belo Horizonte, Brazil.
authors.forename: Daniel
authors.initials: D
authors.lastname: Carvalho de Lima
authors.forename: Juliana Bohnen
authors.initials: JB
authors.lastname: Guimarães
authors.forename: Gisele Vieira
authors.initials: GV
authors.lastname: Rodovalho
authors.forename: Simonton Andrade
authors.initials: SA
authors.lastname: Silveira
authors.forename: Andrea Siqueira
authors.initials: AS
authors.lastname: Haibara
authors.forename: Cândido Celso
authors.initials: CC
authors.lastname: Coimbra
mesh_terms: D000367:Age Factors; D000818:Animals; D004032:Diet; D006321:Heart / Q000502:physiology*; D008297:Male; D009765:Obesity / Q000209:etiology / Q000503:physiopathology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014886:Weaning
keywords: cardiac autonomic balance; cardiac sympathetic tonus; cardiovascular control; contrôle cardiovasculaire; exercice de course; obesity; obésité; palatable diet; running exercise; régime alimentaire sapide; tonus sympathique du cœur; équilibre autonome du cœur