Jordão Maria Tereza, Ladd Fernando V L, Coppi Antonio Augusto, Chopard Renato P, Michelini Lisete C
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
J Vasc Res. 2011;48(6):513-24. doi: 10.1159/000329590. Epub 2011 Aug 10.
BACKGROUND/AIMS: Pharmacological antihypertensive therapies decrease both wall hypertrophy and collagen, but are unable to diminish the elastic content in the thoracic aorta. We investigated the effects of exercise training on aortic structure and function.
Spontaneously hypertensive rats (SHR) and normotensive rats (WKY), submitted to low-intensity training (T) or kept sedentary (S), were subjected to haemodynamic analyses. The thoracic aorta was processed for real-time PCR, light (morphometric/stereological evaluations) and electron microscopy.
SHR(S) versus WKY(S) exhibited a higher heart rate, pressure and pulse pressure, increased α-actin, elastin and collagen mRNA expression, augmented wall volume and cross-sectional area (marked elastin/collagen content). In the SHR, training reduced pressure and heart rate, with slight reduction in pulse pressure. SHR(T) aortas exhibited small morphometric changes, reduced α-actin, elastin and collagen mRNA expression, normalization of increased elastic content, reduction in collagen/connective tissue and a decrease in smooth muscle cell volume (p < 0.05 for all comparisons). SHR(T) aortas showed improved circumferential orientation of smooth muscle cells and prevention of rupture/duplication of internal elastic lamina. No effects were observed in trained WKY aortas.
Training effectively corrects elastic, collagen and smooth muscle content in SHR aortas. These changes, by reducing aortic pulsatility, facilitate a buffering function and reduce the cardiovascular risk.
背景/目的：药物降压疗法可减轻血管壁肥厚和胶原蛋白含量，但无法减少胸主动脉的弹性成分。我们研究了运动训练对主动脉结构和功能的影响。
将自发性高血压大鼠（SHR）和正常血压大鼠（WKY）分为低强度训练组（T）或久坐组（S），进行血流动力学分析。对胸主动脉进行实时聚合酶链反应、光学（形态测量/体视学评估）和电子显微镜检查。
与WKY（S）相比，SHR（S）的心率、血压和脉压更高，α-肌动蛋白、弹性蛋白和胶原蛋白的信使核糖核酸表达增加，血管壁体积和横截面积增大（弹性蛋白/胶原蛋白含量明显增加）。在SHR中，训练可降低血压和心率，脉压略有降低。SHR（T）主动脉的形态测量变化较小，α-肌动蛋白、弹性蛋白和胶原蛋白的信使核糖核酸表达减少，弹性成分增加恢复正常，胶原蛋白/结缔组织减少，平滑肌细胞体积减小（所有比较均P<0.05）。SHR（T）主动脉平滑肌细胞的圆周排列改善，内弹性膜破裂/重复得到预防。训练对WKY主动脉无影响。
训练可有效纠正SHR主动脉的弹性、胶原蛋白和平滑肌成分。这些变化通过降低主动脉搏动性，促进缓冲功能并降低心血管风险。
