心脏肾素－血管紧张素系统在游泳引起的生理性心肌肥大中的作用

ROLE OF CARDIAC RENIN-ANGIOTENSIN SYSTEM IN SWIMMING INDUCED PHYSIOLOGICAL MYOCARDIAL HYPERTROPHY

本实验采用游泳训练（ＳＷ）引起的大鼠心肌肥大模型，通过放射免疫及生化等方法，对生理性心肌肥大时，心脏和循环肾素－血管紧张素系统（ＲＡＳ）的变化进行了初步研究。观察到游泳五周时，大鼠左、右心室重与体重比值（Ｖ／Ｂｗｔ）显著升高，同时，左、右室心肌血管紧张素Ⅱ（ＡｎｇⅡ）含量及心肌Ａｎｇ转换酶（ＡＣＥ）活性也较对照组明显升高（Ｐ＜０．０５）。心肌ＡｎｇⅡ与Ｖ／Ｂｗｔ之间存在明显的正相关关系（ｒ＝０．７７２１，Ｐ＜０．００１）。ＳＷ组血浆ＡｎｇⅠ，Ⅱ及肾素活性（ＲＡ）与对照组相比无明显差异，其血浆ＡｎｇⅡ与Ｖ／Ｂｗｔ之间无明显相关性。上述研究提示：心脏ＲＡＳ在ＳＷ引起的生理性心肌肥大中可能起着重要作用，而且这种作用在很大程度上不依赖于循环ＲＡＳ。

To determine the contribution of cardiac renin-angiotensin system (RAS) to the physiological myocardial hypertrophy induced by swimming training and the relationship between locally produced and circulating RAS, both ventricular and plasma angiotensin (Aug )Ⅰ andⅡ contents, ventricular angiotensin converting enzyme (ACE) and plasma renin activity (PRA) were detected by means of radioimmunoassay and biochemical method. It was shown that after 5 weeks of swimming, the ventricular wet weight to body weight ratio (V/Bwt) and AngⅡ in both left and right ventricles and ACE activity increased markedly as compared with the controls (P<0. 05). Furthermore, significantly possitive correlation was found between the ventricular Ang Ⅱand V/Bwt (r=0. 7721, P<0. 001), while the plasma Ang ⅠandⅡ and PRA remained at the control level. No correlation was found between plasma Ang Ⅱand V/Bwt. These above findings suggest that cardiac RAS may play an important role in physiological myocardial hypertrophy and to a large extent is in dependent on circulating RAS.