大鼠过度训练时RAS的变化意义及Captopril的保护作用

雄性Ｗｉｓｔａｒ大鼠随机分成４组：（１）对照（Ｃ）组；（２）一般游泳训练（ＮＳ）组；（３）过度负荷（Ｏ）组；（４）过度负荷＋Ｃａｐｔｏｐｒｉｌ（ＯＣ）组。游泳训练共8周，建立模拟过度训练动物模型。测定了各组肾素－血管紧张素（ＲＡＳ）活性，并对心肌细胞线粒体钙含量、丙二醛（ＭＤＡ）含量、膜荧光偏振度值、血清肌钙蛋白（ＴｎＴ）含量以及心肌组织ＨＥ染色光镜等指标进行了探讨。对ＲＡＳ各主要成分研究表明，在过度训练状态下，循环和心脏局部ＲＡＳ异常活跃，大鼠心肌发生严重损害是个别现象，大鼠心肌存在钙过载和线粒体膜自由基损伤，上述三者之间有密切相互关系。提示ＲＡＳ在过度训练心肌损害中有重要意义，使用Ｃａｐｔｏｐｒｉｌ后对心肌损害有保护作用。

Role of RAS changes in overtrained myocardial injury in rats and cardioprotective effect of Captopril

Male Wistar rats were randomly divided into four groups: (1)Control group(c); (2)Normal swimming group(NS); (3)Overload swimming group(O); (4)Overload swimming plus Captopril group(OC). Total swimming training was eight weeks. Under the condition of overtraining the RAS activity,level of calcium,malondialdehyde (MDA ) of myocaredial mitochondrial, fluorescence polarization of mitochondrial membrane, serum concentration of troponin T(TnT)and myocardial tissue stained by HE were measured. The results showed that circulatory and cardial local RAS were greatly activated under imitating overtraining condition. The concentration of serum TnT and histologic change of myocardial tissue showed that the serious damages were rarely observed,there are existence of calcium overload and the injury due to free radical in the myocardium in the condition of overtraining.These results suggested that both circulatory and cardiac local RAS are closely related to the calcium overload and the injury by be radical in the overtraining condition. Angiotensin convening enzyme inhibitor (ACEI) - Captopril could effectively inhibit the line of plasma and local AII, preserve the activity of Gpx both in myocardial mitochondrial and in cytosol,attenuate the calcium overload and the injury by be free radical.The results suggested that under the overtraining condition in rats, circulatory and cardiac local RAS are extremely activated,it might have important significance in the myocardial injury, and Captopril might have cardioprotective effect.