Efeitos do treinamento físico aeróbio associado à terapia com células-tronco mesenquimais sobre parâmetros cardiovasculares e propriedades mecânicas de cardiomiócitos em ratos com infarto do miocárdio experimental

• Autor(a) principal: Lavorato, Victor Neiva
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3502
• topic: Infarto do miocárdio; Treinamento físico; Exercícios aeróbicos; Ratos wistar; Células-tronco; Myocardial infarction; Physical training; Aerobic exercises; Wistar rats; Stem cells; CNPQ::CIENCIAS DA SAUDE::EDUCACAO FISICA

The aim of this study was to evaluate the effects of low-intensity aerobic exercise training associated with mesenchymal stem cell therapy (MSCs) on cardiovascular parameters and mechanical properties of cardiomyocytes in rats with experimental myocardial infarction (MI). Male Wistar rats (age: 30 days; body weight: 118 ± 11g) were divided into six groups: control sham (CON SH), trained sham (TR SH), control infarction (CON MI), trained infarction (TR MI), control infarction plus stem cells (CON MI SC) and trained infarction plus stem cells (TR MI SC). Animals from MI groups were subjected to throcotomy ligation of the anterior descending coronary artery. Animals from Sham groups were submitted to the same procedure but ligation of the coronary branch. Animals from TR groups were submitted to a progressive treadmill running training for 12 weeks, being the final duration and intensity of 60 min and 60-70% of maximal running speed, respectively. MSCs from the Wistar rat femoral bone marrow were used to allogenic cell transplantation through the tail vein (concentration: 1 x 106 cells). Hemodynamic analyzes were performed by echocardiography at the end of the experimental period. The infarct size was determined by histomorphometry. The mechanical properties and the intracellular global calcium transient [Ca2+]i were measured using an edge detection system and confocal microscopy, respectively. The expression of calcium regulatory proteins was measured by western blotting. The results showed that the average infarct size was of 30%. Exercise training increased the total time until fatigue in trained animals as compared to their controls. MI decreased the systolic interventricular septum thickness (ESSIV), and the fractions of ejection and shortening of the left ventricle (LV), with increases in the LV diastolic diameter and in the LV systolic diameter (DSVE). At the cellular level, MI increased the amplitude of cell contraction and of [Ca2+]i transient and the time to 50% decay of [Ca2+]i transient. The cellular therapy increased the fractions of ejection and shortening of the LV and reduced the amplitude and the time to 50% decay of the [Ca2+]i transient. Exercise training reduced the DSVE and increased the fractions of ejection and shortening of the LV, the LV thickness and the ESSIV. At the cellular level, exercise training reduced the time to peak of contraction and the time to 50% relaxation and increased the amplitude of the [Ca2+]i transient. It also augmented the expression of the Ca2+ ATPase of the sarcoplasmic reticulum (SERCA 2a) and phospholamban phosphorylated at serine 16 (PLBser16). The combination of exercise training and cellular therapy decreased the time to peak of contraction and increased in the amplitude of the [Ca2+]i transient, as well as the expression of PLBser16. In conclusion, low-intensity exercise training and therapy with MSCs, either isolated or in combination, promotes beneficial adaptations to the heart of rats with experimental MI.