Filho Ary Gomes, Ferreira Anderson J, Santos Sérgio Henrique S, Neves Sílvia R S, Silva Camargos Elizabeth R, Becker Lenice K, Belchior Hindiael A, Dias-Peixoto Marco Fabricio, Pinheiro Sérgio V B, Santos Robson A S
Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
Exp Physiol. 2008 May;93(5):589-98. doi: 10.1113/expphysiol.2007.014293.
In the present study we investigated the effects of physical training on plasma and cardiac angiotensin(1-7) [Ang(1-7)] levels. In addition, possible changes in expression of the Ang(1-7) Mas receptor in the heart were also evaluated. Normotensive Wistar rats and spontaneously hypertensive rats (SHR) were subjected to an 8 week period of 5% overload swimming training. Blood pressure was determined by a tail-cuff system. Heart and left ventricle weights and cardiomyocyte diameter were analysed to evaluate cardiac hypertrophy. Radioimmunoassay was used to measure angiotensin levels. Expression of Mas was determined by semi-quantitative polymerase chain reaction, immunofluorescence and Western blotting. Physical training induced cardiac hypertrophy in Wistar rats and SHR. A significant decrease of plasma angiotensin II (Ang II) levels in both strains was also observed. Strikingly, trained SHR, but not trained Wistar rats, showed a twofold increase in left ventricular Ang(1-7) levels. No significant changes were observed in plasma Ang(1-7) and left ventricular Ang II concentrations in either strain. Furthermore, Mas mRNA and protein expression in left ventricle were substantially increased in trained SHR. The physical training protocol used did not change blood pressure in either strain. These results suggest that the beneficial effects induced by swimming training in hypertensive rats might include an augmentation of Ang(1-7) and its receptor in the heart.
在本研究中，我们调查了体育锻炼对血浆和心脏血管紧张素（1 - 7）[Ang（1 - 7）]水平的影响。此外，还评估了心脏中Ang（1 - 7）Mas受体表达的可能变化。将正常血压的Wistar大鼠和自发性高血压大鼠（SHR）进行为期8周的5%超负荷游泳训练。通过尾套系统测定血压。分析心脏和左心室重量以及心肌细胞直径以评估心脏肥大。采用放射免疫分析法测量血管紧张素水平。通过半定量聚合酶链反应、免疫荧光和蛋白质印迹法测定Mas的表达。体育锻炼在Wistar大鼠和SHR中均诱导了心脏肥大。在这两种品系中还观察到血浆血管紧张素II（Ang II）水平显著降低。令人惊讶的是，训练后的SHR，而非训练后的Wistar大鼠，左心室Ang（1 - 7）水平增加了两倍。在这两种品系中，血浆Ang（1 - 7）和左心室Ang II浓度均未观察到显著变化。此外，训练后的SHR左心室中Mas mRNA和蛋白质表达大幅增加。所采用的体育锻炼方案在两种品系中均未改变血压。这些结果表明，游泳训练在高血压大鼠中诱导的有益作用可能包括心脏中Ang（1 - 7）及其受体的增加。
