Programa de Pós-Graduação em Educação Física, Centro de Educação Física e Desportos, Universidade Federal do Espírito Santo, Vitória, ES, Brasil.
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brasil.
Braz J Med Biol Res. 2021 Jul 16;54(10):e10669. doi: 10.1590/1414-431X2020e10669. eCollection 2021.
Mechanisms involved in cardiac function and calcium (Ca2+) handling in obese-resistant (OR) rats are still poorly determined. We tested the hypothesis that unsaturated high-fat diet (HFD) promotes myocardial dysfunction in OR rats, which it is related to Ca2+ handling. In addition, we questioned whether exercise training (ET) becomes a therapeutic strategy. Male Wistar rats (n=80) were randomized to standard or HFD diets for 20 weeks. The rats were redistributed for the absence or presence of ET and OR: control (C; n=12), control + ET (CET; n=14), obese-resistant (OR; n=9), and obese-resistant + ET (ORET; n=10). Trained rats were subjected to aerobic training protocol with progressive intensity (55-70% of the maximum running speed) and duration (15 to 60 min/day) for 12 weeks. Nutritional, metabolic, and cardiovascular parameters were determined. Cardiac function and Ca2+ handling tests were performed in isolated left ventricle (LV) papillary muscle. OR rats showed cardiac atrophy with reduced collagen levels, but there was myocardial dysfunction. ET was efficient in improving most parameters of body composition. However, the mechanical properties and Ca2+ handling from isolated papillary muscle were similar among groups. Aerobic ET does not promote morphological and cardiac functional adaptation under the condition of OR.
肥胖抵抗（OR）大鼠心脏功能和钙（Ca2+）处理的机制仍不清楚。我们检验了这样一个假设，即不饱和高脂肪饮食（HFD）可促进 OR 大鼠的心肌功能障碍，这与 Ca2+处理有关。此外，我们还质疑运动训练（ET）是否成为一种治疗策略。雄性 Wistar 大鼠（n=80）被随机分为标准或 HFD 饮食 20 周。大鼠被重新分配进行或不进行 ET 和 OR：对照组（C；n=12）、对照组+ET（CET；n=14）、肥胖抵抗组（OR；n=9）和肥胖抵抗+ET（ORET；n=10）。训练大鼠接受渐进强度（最大跑步速度的 55-70%）和持续时间（15 至 60 分钟/天）的 12 周有氧运动训练方案。测定营养、代谢和心血管参数。在分离的左心室（LV）乳头肌中进行心脏功能和 Ca2+处理测试。OR 大鼠表现出心肌萎缩和胶原水平降低，但存在心肌功能障碍。ET 能有效改善身体成分的大多数参数。然而，各组分离乳头肌的机械性能和 Ca2+处理相似。在 OR 条件下，有氧运动 ET 不会促进形态和心脏功能的适应。
