Efeitos do exercício resistido prévio ao infarto do miocárdio sobre a função cardíaca de ratas

• Ano de defesa: 2019
• Autor(a) principal: Silva, Flavio Andre [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Resistance Exercise; Myocardium Infarction; Cardiac Function; Molecular Biology; Rats; Exercício Resistido; Infarto Do Miocárdio; Função Cardíaca; Biologia Molecular; Ratos
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=8065848; https://repositorio.unifesp.br/handle/11600/59391

There is evidence that aerobic exercise prior to myocardial infarction (MI) is capable of generating cardioprotection. However, the cardioprotective properties of resistance exercise (RE) in infarcted rats have been little investigated. Objective: To evaluate the effects of RE prior to myocardial infarction (MI) on cardiac morphology, cardiac function, and proteins that participate in calcium kinetics, associating them with muscle function and cardiorespiratory fitness in female rats. Methods: Wistar rats were distributed into the following groups: SSh: sedentary prior to false surgery (Sham) (n=9); SIM: sedentary prior to MI (n=19); TIM: previously trained to IM (n=13). The exercise program consisted of four sets of 8 to 12 movements carrying weights corresponding to 80% of the maximum load (CM g) five days a week for eight weeks on a rodent-adapted ladder. At the end of the eighth week, the animals underwent MI or sham surgery and were analysed four weeks later. p< 0,05 was considered to be statistically significant. Results: The TIM group rats presented smaller MI (TIM: 43±6,3% e SIM: 55±8,2) and the scar of MI (TIM: 1.2±0,21cm e SIM: 1.6±0,28). Mortality showed no statistical difference (SIM: 37% e TIM: 39). Previous ER mitigated atrial mass increase (mg/mm) (SSh: 1,1±0,1 SIM: 3,8±0,7; TIM: 2,7±0,6), right ventricle (mg/mm) (SSh: 4,5±0,5; SIM: 8,5±2,5; TIM: 6,2±1,0) and heart (mg/mm) (SSh: 22±1; SIM: 29±4; TIM: 26±2) compared to the rats of the SIM group. Left ventricular weight (mg/mm) was similar between groups (SSh: 16,2±0,7, SIM: 16,2±1,5; TIM: 16,9±0,8). The previous RE attenuated the enlargement of the left atrium area (cm²) (SSh: 0,37±0,03; SIM: 0,66±0,09; TIM: 0,52±0,13), wave E (m/s) (SSh: 0,86±0,09; SIM: 1,1±0,13; TIM: 0,97±0,16) and E/A ratio (SSh: 2,9±0,8; SIM: 5,9±1,7; TIM: 4,3±1,8) compared to the rats of the SIM group. The pulmonary water content (SSh: 79,8±0,27%; SIM: 80,71±1,7; TIM: 82,01±2,1) and hepatic (SSh: 70,56±0,1%; SIM: 70,34±0,9; TIM: 71,37±0,7) was superior in TIM. RE slowed down skeletal muscle mass decline (SSh: 0,12±0,01g; SIM: 0,13±0,01; TIM:0,15±0,04). The VO2pico (ml/kg/min) (SSh: 58±6; SIM: 51±10; TIM: 52±6) and maximum speed (Vmáx cm/s) (SSh: 85±12; SIM: 51±10; TIM: 52±6) were inferior in the infarcted. The protein expression (%Sham) of calcium sodium exchanger (NCX) (SSh: 100±32; SIM: 102±29; TIM: 123±39) and total phospholambam (tPLB) (SSh: 100±20; SIM: 86±8; TIM: 86±17) were not different between groups. The protein expression (%Sham) of SERCA2a (SSh: 100±13; SIM: 65±17; TIM:62±14,43) and phosphophorylated phospholambam (pPLB) (SSh: 100±32; SIM: 66±34; TIM: 58±23) were lower in infarcted animals. Conclusion: The RE performed prior to myocardial infarction minimized the size of the MI, alleviated left atrial dissection, attenuated myocardial hypertrophy, and increased muscle mass associated with better strength performance of the skeletal muscles.