Exercise training and caloric restriction prevent reduction in cardiac Ca2+-handling protein profile in obese rats.
Previous studies show that exercise training and caloric restriction improve cardiac function in obesity. However, the molecular mechanisms underlying this effect on cardiac function remain unknown. Thus, we studied the effect of exercise training and/or caloric restriction on cardiac function and Ca(2+) handling protein expression in obese rats. To accomplish this goal, male rats fed with a high-fat and sucrose diet for 25 weeks were randomly assigned into 4 groups: high-fat and sucrose diet, high-fat and sucrose diet and exercise training, caloric restriction, and exercise training and caloric restriction. An additional lean group was studied. The study was conducted for 10 weeks. Cardiac function was evaluated by echocardiography and Ca(2+) handling protein expression by Western blotting. Our results showed that visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels were higher in rats on the high-fat and sucrose diet compared with the lean rats. Cardiac nitrate levels, reduced/oxidized glutathione, left ventricular fractional shortening, and protein expression of phosphorylated Ser(2808)-ryanodine receptor and Thr(17)-phospholamban were lower in rats on the high-fat and sucrose diet compared with lean rats. Exercise training and/or caloric restriction prevented increases in visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels and prevented reduction in cardiac nitrate levels and reduced:oxidized glutathione ratio. Exercise training and/or caloric restriction prevented reduction in left ventricular fractional shortening and in phosphorylation of the Ser(2808)-ryanodine receptor and Thr(17)-phospholamban. These findings show that exercise training and/or caloric restriction prevent cardiac dysfunction in high-fat and sucrose diet rats, which seems to be attributed to decreased circulating neurohormone levels. In addition, this nonpharmacological paradigm prevents a reduction in the Ser(2808)-ryanodine receptor and Thr(17)-phospholamban phosphorylation and redox status.
Paulino
Ellena Christina
EC
Heart Institute InCor, University of Sa˜o Paulo Medical School, Sa˜o Paulo, Brazil.
Ferreira
Julio Cesar Batista
JC
Bechara
Luiz Roberto
LR
Tsutsui
Jeane Mike
JM
Mathias
Wilson
W
Lima
Fabio Bessa
FB
Casarini
Dulce Elena
DE
Cicogna
Antonio Carlos
AC
Brum
Patricia Chakur
PC
Negrão
Carlos Eduardo
CE
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D031204:Caloric Restriction; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000009:adverse effects; D004041:Dietary Fats / Q000008:administration & dosage / Q000009:adverse effects; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009765:Obesity / Q000209:etiology / Q000517:prevention & control*; D010766:Phosphorylation; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism; D013395:Sucrose / Q000008:administration & dosage / Q000009:adverse effects; D016277:Ventricular Function, Left / Q000502:physiology; D000099211:Phospholamban
D002118:Calcium; D002135:Calcium-Binding Proteins; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017868:Cyclic AMP-Dependent Protein Kinases; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D019837:Ryanodine Receptor Calcium Release Channel; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D013395:Sucrose; D000099211:Phospholamban; C506948:Atp2a2 protein, rat